Boston Property Tax Bills

This post is still a draft subject to correction.

This post is intended as a reference document to support the conversation about Boston property tax bills. The outline below summarizes the content. Overall, Boston residential tax rates are relatively low by statewide standards, but this year brought two kinds of shifts in relative value. First, the property tax burden shifts somewhat from commercial to residential due to declines in commercial values. Second, due to FY25 being a revaluation year, there more dramatic burden shifts among residential properties. Some residential properties show deep tax reductions; some show sharp increases. The shifts among residential properties are dispersed across neighborhoods and residential property types, but the shifts among residential properties do not appear to be wider than in the last valuation. Of note, there is split between small residential properties (up to 3 family), which generally increased in value, while large residential properties (excluding luxury apartments) declined on average in value.

• Boston tax rates
  • Transparency of valuations in Boston
  • Setting the tax rates
  • Effective tax rates with the residential exemption
  • Comparing tax rates
    • Tax rate comparisons for Fiscal 2025 among Massachusetts Communities
    • Change in tax bills
• Patterns of change
  • Citywide declines in commercial values
  • Large residential valuation shifts
  • Value changes by neighborhood and property type
  • Wide variation in residential tax bill increases
  • Where are tax bill increases greatest?
• Are the changes more than should be expected?
• Data resources

Boston tax rates

Transparency of valuations in Boston

Every conversation about taxes in Boston should start with appreciation for the work that the Boston assessors do. Property tax assessment in Boston is professional, transparent, and motivated by a desire for accuracy. Estimating the individual market values of over 180,000 properties is no small task and requires diligence and expertise. The results cannot be perfect, and market values are perennially debatable, but I personally respect the process and appreciate how much better the process is today than it was 50 years ago.

Fifty years ago, property valuations in Boston and in many other Massachusetts communities were a disaster: Property valuations were decades out of date, wildly inaccurate, apparently political, and even racially biased. Valuations in Roxbury were as much as twice the valuations of comparably valuable homes in South Boston. In the 70s and the 80s, a combination of court decisions, popular referenda, and legislative actions empowered state regulators to compel communities to align their assessed values with true market values. Today, we have a system that preserves local control of the assessment process within a state regulatory framework defined and overseen by the state department of revenue’s division of local services. In general, there is a strong partnership between DLS and local assessors and together they administer a system that is recognized as a model for other jurisdictions to aspire to. For a history of property tax assessment reform in Massachusetts, view Successful Property Tax Reform: The Case of Massachusetts offered by the Lincoln Land Institute (the online course is free, requires about 90 minutes, and can be started immediately upon online registration).

All of the analysis in this post is possible only because we have a transparent property tax system in Massachusetts. Almost all information of interest about property taxes is publicly available at the state’s Municipal Data Bank. Boston does an especially nice job making valuations (and building permit data) for each year available for download at the city’s site. All communities report their valuations to DLS and the state publishes a consolidated map of all valuations online.

Setting the tax rates

The table below summarizes by property class the total values for the over 180,000 properties in the downloaded Boston Assessment Data for years FY24 and FY25. The table shows the overall increase in residential and the overall decrease in commercial which has been widely discussed.

Class	FY2024 Total Valuation	FY 2025 Total Valuation	%change
Multiple Use	17,632,903,291	18,035,127,142	2.3%
Residential	133,275,507,003	139,476,934,900	4.7%
Commercial	59,381,307,652	57,771,098,413	-2.7%
Industrial	1,403,466,881	1,404,912,654	0.1%
Agricultural*	670,700	641,900	-4.3%
Total	211,693,855,527	216,688,715,009	2.4%

Working from these downloaded real property valuations to the actual tax rates and tax bills for FY25 involves the following steps, computations for which are detailed in this spreadsheet. Knowing that these steps can be worked mathematically from the download through to the bills gives confidence in the downloaded data.

1. Add in valuations for personal property ($9.7 billion) which are not reflected in the online real estate database to get a final total valuation ($226.4 billion).
2. Compute the total tax levy as the maximum tax levy authorized by Proposition 2.5 ($3.359 billion) and adjust it down just a little bit to allow for final tax rates that are exact to the penny ($3.358 billion).
3. Compute the overall effective tax rate as the total tax levy divided by the total valuation ($14.83 per $1000)
4. Allocate the valuation of multiple use real properties between residential and non-residential (commercial, industrial, personal) — the resulting total valuation split is 68.0% residential and 32.0% non-residential.
5. Boost the non-residential tax rate to 175% of the overall tax rate (175% * $14.83 = $25.96) — this is the step which shifts taxes from residential taxpayers to non-residential taxpayers.
6. Apply the boosted tax rate to the non-residential valuation to compute the non-residential portion of the levy ($1.878 billion or 55.9%)
7. Compute the residential exemption as the simple average value of all properties classified as residential, including not only single family and multi-family dwellings, but condo parking spaces, condo storage areas, vacant lots zoned residential, etc. ($344,060). This computation also includes the allocated residential value of multiple use properties.
8. Back out the exemptions for owner-occupied parcels (77,003) from the residential valuations to compute a net residential valuation for purposes of computing the residential tax rate. The final exact version of this computation reflects that the residential exemption is the lesser of $344,060 and 90% of the value of the property. This cuts the taxable residential valuation from $154.0 billion to $127.8 billion.
9. Compute the residential levy as the total tax levy less the boosted non-residential portion of the levy, $1.480 billion or 44.1%.
10. Compute the nominal residential tax rate as the residential tax levy divided by the net residential valuation: $11.58 (this rate compares to $9.61, the effective rate that would produce the same levy if there were no residential exemption).

The final rates are summarized in the table below:

Boston tax rates FY24 and FY25

	Boston FY24	Boston FY25
Residential nominal rate	$10.90	$11.58
Residential effective rate (residential levy divided by gross residential value, value not reduced by residential exemption)	$9.02	$9.61
Commercial rate	$25.27	$25.96
Overall average rate for all property classes (total levy divided by gross value, value not reduced by residential exemption))	$14.44	$14.83

Effective tax rates with the residential exemption

As noted above, in Boston, for owner occupants, individual property tax bills are reduced by the residential exemption. The exemption amount is $344,060 in FY 2025. The taxable valuation of a property is the full assessed valuation less the exemption (but not less than 10% of the valuation). The tax bill is computed as the nominal tax rate ($11.58) times the taxable valuation. As noted above, the nominal tax rate is increased (from $9.61 in FY25) to preserve the size of the residential levy when the total taxable valuation is reduced by the exemption.

The exemption results in a range of tax rates for different properties from as little as $1.16 per thousand up to $11.58 per thousand. Lower value owner-occupied properties have reduced tax bills and reduced effective tax rates because as much as 90% of their value may be exempt. The solid blue line in the chart below shows the distribution of effective tax rates across all Boston residential properties net of the exemption. The rate tops out at the full nominal $11.58 applicable to the roughly half of properties that are not owner-occupied and not eligible for the exemption.

Boston residential properties arrayed by FY25 effective tax rate net of exemption
(vertical axis is $ per 1000; horizontal access is percentile among residential properties)

The following observations can be made from the chart above:

• Almost 50% of Boston taxpayers pay less (most of them much less) than the statewide average residential tax rate ($10.54). These are all owner-occupants who benefit from the residential exemption.
• 3% pay only $1.16 per 1,000 (the minimum amount after the exemption).
• A typical owner-occupant pays approximately $6 per $1,000.
• Non-owner-occupants pay the full nominal rate $11.58 per $1,000 which is above the statewide average rate of $10.54.
• The city’s proposed tax shift from residential to commercial would lower all of these rates slightly.

Comparing tax rates

The table below offers several comparisons of tax rates. The table is sorted to put the largest communities at the top, but the reader can select and sort within the table. A few observations about Boston’s 2025 tax rates:

• Boston’s residential tax levy is among the lowest as a percentage of personal income — Boston ranks 332nd out of the 351 Massachusetts communities on that measure. Only 19 communities have lower residential taxes as percent of income. These include some communities which have very high income and a few other communities who, like Boston, are able to shift the residential burden to businesses.
• Boston’s nominal residential tax rate (not reflecting the residential exemption) ranks 216th from the top among the state’s 351 communities.
• Boston’s effective residential tax rate (truly reflecting the residential exemption) ranks 290th from the top.
• Boston’s nominal residential rate is above a majority of the 19 other largest communities, but Boston’s effective rate is below that of a majority of those communities.
• For many Boston homeowners benefiting from the residential exemption, the Fiscal 2025 effective tax rates are among the lowest in the state: as shown above, effective tax rates for Boston homeowners with exemptions are variable but roughly half are below $6 per thousand). Only 15 communities (most of them seasonal communities) have effective tax rates below $6 (although approximately 10 more may have tax rates are similarly low for some of their homeowners because of a residential exemptions).

Tax rate comparisons for Fiscal 2025 among Massachusetts Communities

Municipality	Population	DOR Income Per Capita	Nominal Residential Rate	Effective Residential Rate	Residential Levy as % of Income	Residential levy per capita
Boston	650,706	76,780	$11.58	$9.61	2.96%	$ 2,274
Worcester	205,319	25,451	$13.19	$13.19	4.85%	$ 1,234
Springfield	154,064	19,256	$15.68	$15.68	5.52%	$ 1,063
Cambridge	118,488	93,288	$6.35	$5.29	1.92%	$ 1,793
Lowell	113,608	26,787	$11.48	$11.48	4.65%	$ 1,245
Brockton	104,826	24,698	$12.11	$12.11	5.21%	$ 1,287
Quincy	101,727	43,000	$11.53	$11.53	5.38%	$ 2,312
Lynn	100,891	25,320	$10.36	$10.36	5.38%	$ 1,362
New Bedford	100,682	21,627	$11.31	$11.31	5.10%	$ 1,103
Fall River	93,682	21,636	$11.45	$11.45	4.88%	$ 1,056
Lawrence	87,954	20,915	$8.80	$8.80	3.30%	$ 690
Newton	87,381	239,346	$9.80	$9.80	1.81%	$ 4,334
Somerville	79,762	59,654	$10.91	$8.90	3.71%	$ 2,214
Framingham	70,963	47,632	$11.94	$11.94	4.44%	$ 2,115
Haverhill	67,153	34,981	$10.71	$10.71	4.54%	$ 1,587
Medford	65,399	47,556	$8.80	$8.80	3.98%	$ 1,894
Malden	64,712	34,334	$11.32	$9.17	4.13%	$ 1,417
Plymouth	64,269	48,564	$12.69	$12.69	6.35%	$ 3,085
Waltham	64,065	50,143	$9.82	$7.22	2.94%	$ 1,473
Brookline	62,535	129,576	$9.87	$8.75	3.24%	$ 4,193
Taunton	59,922	30,438	$10.94	$10.94	4.81%	$ 1,464
Revere	58,528	30,194	$9.07	$9.07	5.15%	$ 1,556
Weymouth	57,410	44,810	$10.10	$10.10	4.46%	$ 1,997
Chicopee	54,980	24,527	$15.16	$15.16	5.22%	$ 1,280
Peabody	53,896	40,322	$9.26	$9.26	4.27%	$ 1,723
Methuen	53,241	37,061	$10.58	$10.58	4.55%	$ 1,686
Barnstable	49,532	53,740	$6.94	$6.10	5.08%	$ 2,732
Everett	49,350	25,543	$11.39	$10.07	5.43%	$ 1,387
Attleboro	46,601	39,991	$12.55	$12.55	4.32%	$ 1,729
Arlington	45,522	88,688	$10.77	$10.77	3.90%	$ 3,459
Salem	44,722	39,587	$11.34	$11.34	4.99%	$ 1,975
Leominster	43,646	34,695	$14.03	$14.03	4.93%	$ 1,712
Pittsfield	43,310	31,497	$17.94	$17.94	5.63%	$ 1,774
Beverly	42,235	62,463	$10.99	$10.99	3.88%	$ 2,424
Fitchburg	41,502	25,471	$13.51	$13.51	5.29%	$ 1,347
Billerica	41,319	51,246	$11.37	$11.37	4.69%	$ 2,403
Woburn	41,248	53,893	$8.54	$8.54	3.37%	$ 1,819
Marlborough	40,971	42,729	$9.86	$9.86	3.82%	$ 1,633
Westfield	40,535	34,361	$15.18	$15.18	4.48%	$ 1,538
Amherst	40,059	23,779	$17.95	$17.95	6.30%	$ 1,497
Shrewsbury	39,805	72,635	$12.04	$12.04	3.45%	$ 2,506
Chelsea	38,637	24,704	$11.51	$9.75	4.54%	$ 1,121
Braintree	38,567	53,799	$9.98	$9.98	3.96%	$ 2,133
Holyoke	37,720	22,368	$17.46	$17.46	4.92%	$ 1,101
Andover	36,363	119,706	$12.49	$12.47	3.11%	$ 3,721
Natick	36,272	80,295	$11.96	$11.96	4.14%	$ 3,327
Chelmsford	35,906	66,946	$13.90	$13.90	4.27%	$ 2,860
Watertown	35,022	62,475	$11.68	$9.17	3.85%	$ 2,407
Randolph	34,530	33,603	$11.61	$11.61	5.34%	$ 1,794
Lexington	34,074	174,217	$12.23	$12.23	3.29%	$ 5,735
Franklin	33,656	64,184	$11.62	$11.62	3.67%	$ 2,353
Dartmouth	33,406	49,314	$8.26	$8.26	3.62%	$ 1,785
Falmouth	33,104	62,029	$5.87	$5.87	5.86%	$ 3,632
Needham	32,114	169,870	$10.60	$10.60	2.72%	$ 4,622
Dracut	32,060	42,616	$10.12	$10.12	4.06%	$ 1,729
Norwood	31,317	52,847	$10.52	$10.52	3.75%	$ 1,979
North Andover	31,295	81,207	$11.26	$11.26	3.09%	$ 2,512
North Attleborough	30,930	55,139	$11.79	$11.79	3.47%	$ 1,912
Tewksbury	30,833	51,763	$13.22	$13.22	5.31%	$ 2,747
Wellesley	30,524	334,709	$10.28	$10.28	1.58%	$ 5,280
Milford	30,196	39,858	$12.80	$12.80	4.98%	$ 1,984
Gloucester	29,836	58,837	$9.72	$9.72	5.50%	$ 3,237
Northampton	29,327	45,873	$13.93	$13.93	4.88%	$ 2,240
Melrose	29,155	67,216	$9.90	$9.90	3.71%	$ 2,493
Stoughton	28,969	41,746	$12.38	$12.38	5.13%	$ 2,142
Bridgewater	28,780	41,141	$11.83	$11.83	4.38%	$ 1,800
Saugus	28,547	44,588	$10.68	$10.68	5.02%	$ 2,238
West Springfield	28,501	36,399	$14.87	$14.87	3.99%	$ 1,453
Agawam	28,393	35,689	$14.64	$14.64	4.92%	$ 1,756
Milton	28,364	100,620	$11.09	$11.09	3.34%	$ 3,360
Danvers	27,781	60,349	$10.99	$10.99	3.91%	$ 2,360
Wakefield	27,069	61,962	$11.35	$11.28	4.57%	$ 2,833
Belmont	26,710	140,907	$11.39	$11.39	3.33%	$ 4,695
Walpole	26,277	71,933	$12.83	$12.83	4.31%	$ 3,101
Burlington	25,966	66,067	$8.66	$8.66	3.22%	$ 2,129
Marshfield	25,713	67,082	$9.90	$9.90	4.53%	$ 3,039
Yarmouth	25,244	44,804	$7.08	$7.08	6.41%	$ 2,873
Easton	25,240	65,359	$12.48	$12.48	3.88%	$ 2,534
Reading	25,205	84,143	$11.39	$11.33	3.92%	$ 3,299
Dedham	24,997	77,892	$12.62	$12.62	4.13%	$ 3,217
Canton	24,609	78,194	$9.89	$9.89	3.11%	$ 2,433
Middleborough	24,376	37,564	$13.41	$13.41	5.44%	$ 2,042
Westford	24,353	82,731	$13.47	$13.47	4.29%	$ 3,551
Hingham	24,130	187,681	$10.69	$10.69	2.28%	$ 4,275
Acton	23,829	92,784	$17.15	$17.15	4.68%	$ 4,339
Mansfield	23,816	61,467	$13.17	$13.17	4.01%	$ 2,467
Wareham	23,151	31,782	$8.55	$8.55	6.05%	$ 1,924
Wilmington	22,904	58,187	$11.45	$11.45	4.68%	$ 2,721
Stoneham	22,705	59,977	$10.23	$10.23	4.16%	$ 2,496
Winchester	22,640	175,805	$11.09	$11.09	3.03%	$ 5,327
Westborough	21,506	80,712	$16.29	$16.29	4.09%	$ 3,300
Gardner	20,902	25,784	$14.36	$14.36	5.27%	$ 1,360
Ludlow	20,871	35,908	$17.35	$17.35	5.79%	$ 2,081
Bourne	20,667	50,375	$7.81	$7.81	5.34%	$ 2,691
Sandwich	20,611	57,701	$10.57	$10.57	5.90%	$ 3,407
Marblehead	20,233	130,610	$9.05	$9.05	3.05%	$ 3,983
Holden	19,880	56,534	$13.86	$13.86	4.51%	$ 2,550
Grafton	19,815	62,569	$13.94	$13.94	4.32%	$ 2,703
Hudson	19,744	49,853	$13.88	$13.88	5.34%	$ 2,661
Hopkinton	19,249	115,194	$14.18	$14.16	3.58%	$ 4,124
Scituate	19,190	94,999	$9.99	$9.99	4.35%	$ 4,134
Norton	19,108	47,373	$12.97	$12.97	4.53%	$ 2,145
Sudbury	18,965	155,522	$14.64	$14.59	3.36%	$ 5,225
Newburyport	18,662	87,382	$9.58	$9.58	3.94%	$ 3,439
Winthrop	18,510	45,268	$10.32	$10.32	4.41%	$ 1,996
Foxborough	18,488	74,729	$13.22	$13.22	3.44%	$ 2,571
Ashland	18,466	67,924	$12.77	$12.77	4.26%	$ 2,895
Sharon	18,408	89,747	$17.48	$17.48	4.96%	$ 4,449
Pembroke	18,297	52,327	$12.02	$12.02	4.75%	$ 2,485
Somerset	18,192	39,559	$13.30	$13.30	5.56%	$ 2,199
South Hadley	18,046	38,780	$13.98	$13.98	4.48%	$ 1,739
Concord	17,954	226,782	$13.26	$12.41	2.66%	$ 6,040
Greenfield	17,656	27,133	$19.56	$19.56	6.61%	$ 1,795
Southbridge	17,619	24,588	$14.66	$14.66	5.20%	$ 1,278
Rockland	17,609	36,166	$13.67	$13.67	5.95%	$ 2,150
Webster	17,601	35,584	$11.88	$11.88	4.41%	$ 1,570
Bellingham	17,407	42,868	$12.56	$12.56	4.90%	$ 2,099
Swansea	17,307	40,531	$10.98	$10.98	4.97%	$ 2,014
Amesbury	17,179	48,024	$15.30	$15.30	6.37%	$ 3,061
Abington	16,965	42,780	$13.06	$13.06	5.34%	$ 2,283
Auburn	16,762	42,242	$14.29	$14.29	5.09%	$ 2,150
Westport	16,413	56,741	$7.45	$7.45	3.92%	$ 2,222
East Longmeadow	16,343	52,249	$18.48	$18.48	5.15%	$ 2,691
Northbridge	16,337	44,990	$11.79	$11.79	3.94%	$ 1,770
Westwood	16,231	155,744	$12.80	$12.80	3.09%	$ 4,814
Duxbury	16,107	130,414	$10.14	$10.14	3.38%	$ 4,413
Easthampton	16,045	36,112	$13.67	$13.67	5.08%	$ 1,835
Fairhaven	15,837	41,830	$9.32	$9.32	4.06%	$ 1,696
Northborough	15,663	76,367	$14.25	$14.25	3.93%	$ 2,999
Seekonk	15,649	48,536	$12.35	$12.35	4.71%	$ 2,288
Longmeadow	15,632	114,925	$21.12	$21.12	3.33%	$ 3,824
North Reading	15,549	85,288	$13.06	$13.06	4.32%	$ 3,688
Clinton	15,484	34,975	$13.30	$13.30	4.72%	$ 1,650
Raynham	15,474	48,678	$12.10	$12.10	4.34%	$ 2,111
Mashpee	15,468	57,264
Belchertown	15,316	41,992	$14.51	$14.51	5.03%	$ 2,113
Swampscott	15,280	93,266	$11.47	$11.47	3.63%	$ 3,386
Whitman	15,259	38,112	$13.12	$13.12	5.38%	$ 2,050
Dennis	14,932	54,924	$4.33	$4.33	6.32%	$ 3,472
Holliston	14,856	80,153	$14.65	$14.65	4.40%	$ 3,529
Hanover	14,758	74,032	$12.35	$12.35	4.17%	$ 3,087
Wilbraham	14,526	54,366	$17.88	$17.88	5.34%	$ 2,905
Nantucket	14,421	104,521	$3.28	$3.11	7.49%	$ 7,826
Uxbridge	14,386	45,489	$13.11	$13.11	4.93%	$ 2,241
East Bridgewater	14,338	42,736	$13.67	$13.67	5.32%	$ 2,276
Bedford	14,161	104,718	$12.04	$12.04	3.49%	$ 3,653
Millbury	13,936	42,232	$13.39	$13.39	5.29%	$ 2,235
Ipswich	13,848	81,006	$11.15	$11.15	4.23%	$ 3,423
Kingston	13,829	52,167	$12.97	$12.97	5.33%	$ 2,782
Wayland	13,664	227,716	$15.63	$15.63	2.75%	$ 6,261
Harwich	13,647	54,236	$5.91	$5.91	7.60%	$ 4,124
Medway	13,393	65,077	$14.25	$14.25	4.69%	$ 3,051
Charlton	13,360	46,852	$11.13	$11.13	4.00%	$ 1,876
Oxford	13,287	37,155	$12.67	$12.67	4.86%	$ 1,804
Medfield	13,072	136,384	$13.80	$13.80	3.00%	$ 4,094
Rehoboth	13,023	55,533	$11.15	$11.15	4.19%	$ 2,329
Lynnfield	12,951	107,831	$10.56	$10.56	3.32%	$ 3,585
North Adams	12,777	19,982	$16.71	$16.71	5.68%	$ 1,134
Wrentham	12,457	74,021	$11.59	$11.59	3.67%	$ 2,718
Tyngsborough	12,368	56,004	$12.34	$12.34	4.39%	$ 2,460
Palmer	12,337	29,777	$16.48	$16.48	5.65%	$ 1,682
Spencer	11,911	33,700	$11.74	$11.74	4.60%	$ 1,550
Athol	11,897	25,016	$12.71	$12.71	5.30%	$ 1,325
Lakeville	11,895	52,768	$10.35	$10.35	4.24%	$ 2,235
Dudley	11,850	34,084	$10.57	$10.57	4.13%	$ 1,408
Lunenburg	11,835	48,694	$14.36	$14.36	5.38%	$ 2,622
Weston	11,661	551,525	$11.10	$11.10	1.44%	$ 7,935
Carver	11,626	38,190	$13.87	$13.87	5.84%	$ 2,229
Pepperell	11,620	49,412	$14.63	$14.63	5.05%	$ 2,495
Norfolk	11,552	74,137	$15.97	$15.97	4.72%	$ 3,500
Holbrook	11,285	37,374	$13.18	$13.18	5.72%	$ 2,139
Norwell	11,280	132,335	$13.07	$13.07	3.28%	$ 4,337
Groton	11,162	87,562	$15.25	$15.25	4.18%	$ 3,662
Leicester	11,033	38,693	$11.77	$11.77	4.24%	$ 1,641
Hanson	10,587	46,839	$13.38	$13.38	5.22%	$ 2,444
Acushnet	10,585	40,392	$10.79	$10.79	4.54%	$ 1,834
Maynard	10,546	51,469	$17.83	$17.83	6.64%	$ 3,417
Brewster	10,444	52,538	$6.88	$6.88	8.29%	$ 4,358
Southborough	10,409	154,628	$13.81	$13.81	2.73%	$ 4,228
Winchendon	10,385	27,321	$11.75	$11.75	4.80%	$ 1,312
Ware	10,385	26,488	$15.06	$15.06	5.60%	$ 1,484
Hull	10,142	59,593	$11.20	$11.20	6.00%	$ 3,575
Littleton	10,139	75,339	$14.86	$14.86	4.75%	$ 3,577
Sturbridge	9,882	57,354	$15.93	$15.93	4.87%	$ 2,795
Plainville	9,865	50,487	$11.56	$11.56	3.82%	$ 1,929
Middleton	9,837	78,028	$11.89	$11.89	4.27%	$ 3,333
Sutton	9,379	67,471	$12.02	$12.02	4.05%	$ 2,733
Rutland	9,298	46,736	$14.24	$14.24	4.91%	$ 2,293
Freetown	9,236	45,931	$9.91	$9.91	4.23%	$ 1,943
Blackstone	9,211	38,481	$15.10	$15.10	5.29%	$ 2,037
Southwick	9,190	47,037	$15.57	$15.57	5.08%	$ 2,392
Salisbury	9,189	41,812	$10.08	$10.08	6.14%	$ 2,565
Douglas	9,153	47,942	$13.17	$13.17	4.70%	$ 2,253
Townsend	8,948	41,852	$14.52	$14.52	5.36%	$ 2,243
Millis	8,836	59,944	$16.40	$16.40	6.11%	$ 3,661
Montague	8,463	27,855	$15.21	$15.21	5.61%	$ 1,563
Ayer	8,424	44,451	$11.96	$11.96	4.32%	$ 1,919
Georgetown	8,408	62,148	$11.06	$11.06	4.38%	$ 2,720
Lancaster	8,394	47,134	$16.16	$16.16	5.30%	$ 2,499
Cohasset	8,346	185,475	$11.58	$11.58	3.01%	$ 5,582
Westminster	8,330	48,570	$12.30	$12.30	4.62%	$ 2,242
Templeton	8,183	33,081	$12.12	$12.12	4.79%	$ 1,585
Dighton	8,168	42,730	$12.56	$12.56	5.20%	$ 2,221
Sterling	8,139	59,945	$12.88	$12.88	4.30%	$ 2,578
Upton	8,128	68,878	$13.15	$13.15	4.33%	$ 2,983
Boxford	8,112	144,840	$13.45	$13.45	3.06%	$ 4,426
Monson	8,090	37,482	$14.87	$14.87	5.28%	$ 1,981
Adams	8,047	26,598	$17.01	$17.01	5.45%	$ 1,449
West Boylston	7,757	45,451	$13.87	$13.87	5.24%	$ 2,383
Halifax	7,698	41,693	$14.27	$14.27	5.85%	$ 2,440
Williamstown	7,663	47,254	$13.80	$13.80	5.12%	$ 2,419
West Bridgewater	7,625	44,799	$13.67	$13.67	5.32%	$ 2,381
Orange	7,558	24,059	$16.45	$16.45	6.94%	$ 1,669
Hamilton	7,526	107,398	$15.65	$15.65	4.26%	$ 4,573
Great Barrington	7,214	58,612	$13.79	$13.79	5.90%	$ 3,456
Stow	7,042	96,844	$17.42	$17.42	4.82%	$ 4,671
Rockport	6,925	69,656	$8.76	$8.76	5.77%	$ 4,021
Harvard	6,870	85,831	$15.65	$15.63	4.62%	$ 3,964
Lincoln	6,855	208,365	$12.81	$12.81	2.56%	$ 5,333
Berkley	6,797	47,561	$12.01	$12.01	4.82%	$ 2,294
Shirley	6,782	39,141	$12.97	$12.97	4.74%	$ 1,857
Groveland	6,721	51,825	$12.69	$12.69	5.52%	$ 2,863
Chatham	6,711	95,522	$3.47	$3.47	6.31%	$ 6,030
Merrimac	6,699	47,736	$13.25	$13.25	5.68%	$ 2,711
Newbury	6,695	127,380	$7.45	$7.45	2.32%	$ 2,954
Mattapoisett	6,589	75,605	$10.76	$10.76	5.54%	$ 4,188
Topsfield	6,504	97,237	$14.99	$14.99	4.55%	$ 4,426
Orleans	6,422	74,862	$6.24	$6.24	8.17%	$ 6,117
Ashburnham	6,372	39,549	$14.87	$14.87	6.58%	$ 2,602
Mendon	6,286	77,459	$13.39	$13.39	3.80%	$ 2,946
Rowley	6,283	59,762	$11.77	$11.77	4.87%	$ 2,908
Dalton	6,236	39,672	$16.47	$16.47	5.49%	$ 2,177
Southampton	6,207	54,934	$14.17	$14.17	4.23%	$ 2,326
Granby	6,055	41,187	$15.37	$15.37	5.82%	$ 2,398
Hopedale	6,008	49,114	$16.61	$16.61	5.59%	$ 2,744
Dover	5,860	361,388	$11.27	$11.27	1.85%	$ 6,687
Eastham	5,822	50,199	$7.71	$7.71	12.81%	$ 6,430
Rochester	5,816	52,832	$10.82	$10.82	4.78%	$ 2,528
Bolton	5,728	99,220	$16.62	$16.62	4.61%	$ 4,576
Lee	5,707	39,565	$11.25	$11.25	5.02%	$ 1,988
Barre	5,533	32,869	$13.59	$13.59	5.15%	$ 1,693
Boxborough	5,412	92,804	$15.14	$15.14	4.39%	$ 4,079
Oak Bluffs	5,379	35,050	$5.05	$4.91	15.46%	$ 5,419
Manchester By The Sea	5,354	240,634	$9.15	$9.15	2.42%	$ 5,828
Marion	5,291	90,361	$9.32	$9.32	4.69%	$ 4,233
Hadley	5,270	42,487	$11.63	$11.63	4.71%	$ 2,000
Edgartown	5,266	92,802	$2.65	$2.65	7.30%	$ 6,772
Deerfield	5,162	54,070	$13.25	$13.25	3.93%	$ 2,127
Carlisle	5,157	206,865	$13.18	$13.18	2.92%	$ 6,032
Lenox	5,064	71,325	$9.05	$9.05	3.87%	$ 2,759
Paxton	5,024	47,691	$14.74	$14.74	5.13%	$ 2,446
Warren	4,968	23,579	$14.81	$14.81	6.35%	$ 1,498
Wenham	4,926	108,662	$15.54	$15.54	3.90%	$ 4,239
Boylston	4,924	78,749	$13.83	$13.83	4.22%	$ 3,321
Hampden	4,915	53,288	$15.09	$15.09	4.79%	$ 2,550
Tisbury	4,886	31,005	$7.57	$6.93	21.91%	$ 6,792
Avon	4,735	45,108	$13.34	$13.34	4.83%	$ 2,177
North Brookfield	4,728	34,421	$14.17	$14.17	5.06%	$ 1,742
West Newbury	4,562	94,138	$10.80	$10.80	3.75%	$ 3,527
Sherborn	4,372	328,012	$16.58	$16.58	2.07%	$ 6,788
Hubbardston	4,335	44,903	$11.68	$11.68	4.23%	$ 1,901
Berlin	4,189	60,934	$14.19	$14.19	4.68%	$ 2,849
West Brookfield	3,817	44,837	$10.78	$10.78	3.74%	$ 1,675
Provincetown	3,723	103,933	$5.60	$5.22	6.58%	$ 6,840
Brimfield	3,690	44,744	$14.14	$14.14	4.97%	$ 2,225
Essex	3,668	126,795	$12.99	$12.99	3.40%	$ 4,312
Sunderland	3,647	59,903	$13.02	$13.02	3.14%	$ 1,882
Wellfleet	3,644	54,944	$7.11	$6.63	13.39%	$ 7,359
West Tisbury	3,594	44,013	$4.53	$4.47	12.91%	$ 5,684
Princeton	3,504	72,563	$14.53	$14.53	4.37%	$ 3,168
Brookfield	3,432	34,762	$15.48	$15.48	5.25%	$ 1,825
Dunstable	3,355	75,690	$13.75	$13.75	4.44%	$ 3,361
Sheffield	3,329	56,572	$12.11	$12.11	4.97%	$ 2,812
Hatfield	3,314	43,837	$13.84	$13.84	5.77%	$ 2,530
Nahant	3,289	85,154	$9.15	$9.15	4.44%	$ 3,782
Cheshire	3,215	36,195	$11.13	$11.13	3.91%	$ 1,417
Ashby	3,163	38,265	$15.23	$15.23	6.31%	$ 2,413
Millville	3,147	38,482	$13.19	$13.19	4.64%	$ 1,785
Lanesborough	3,016	38,153	$16.73	$16.73	7.20%	$ 2,748
Plympton	2,923	52,909	$15.89	$15.89	5.80%	$ 3,067
Northfield	2,872	38,182	$13.84	$13.84	5.28%	$ 2,014
Hardwick	2,658	28,673	$13.15	$13.15	5.85%	$ 1,676
Holland	2,573	37,165	$12.98	$12.98	6.87%	$ 2,555
Truro	2,486	60,222	$6.18	$5.73	14.00%	$ 8,431
Williamsburg	2,469	32,318	$18.97	$18.97	8.61%	$ 2,783
East Brookfield	2,204	38,251	$12.84	$12.84	5.35%	$ 2,046
Bernardston	2,104	37,494	$14.27	$14.27	5.32%	$ 1,996
Huntington	2,069	36,340	$15.40	$15.40	5.80%	$ 2,106
Stockbridge	1,998	68,401	$7.09	$7.09	6.37%	$ 4,357
Becket	1,931	36,209	$8.76	$8.76	8.69%	$ 3,147
Hinsdale	1,900	45,888	$11.15	$11.15	4.83%	$ 2,214
Shelburne	1,886	25,360	$12.84	$12.84	7.37%	$ 1,870
Oakham	1,866	41,435	$11.55	$11.55	4.56%	$ 1,889
Leverett	1,860	50,504	$15.18	$15.18	6.05%	$ 3,054
Buckland	1,810	25,403	$16.94	$16.94	9.58%	$ 2,433
Wales	1,807	28,823	$14.42	$14.42	7.02%	$ 2,022
Conway	1,760	47,767	$14.44	$14.44	5.80%	$ 2,769
Shutesbury	1,726	36,879	$15.83	$15.83	8.36%	$ 3,082
Phillipston	1,720	37,027	$11.27	$11.27	6.35%	$ 2,351
Ashfield	1,688	48,790	$13.46	$13.46	5.43%	$ 2,650
Erving	1,667	36,000	$9.31	$9.31	2.78%	$ 1,001
Clarksburg	1,643	29,474	$13.58	$13.58	4.49%	$ 1,323
Russell	1,631	37,015	$18.30	$18.30	5.98%	$ 2,213
Otis	1,626	50,272	$6.46	$6.46	7.01%	$ 3,526
Whately	1,623	25,928	$13.34	$13.34	9.33%	$ 2,419
Westhampton	1,620	49,506	$20.79	$20.79	6.75%	$ 3,341
Colrain	1,617	32,466	$18.26	$18.26	6.69%	$ 2,172
Gill	1,560	28,162	$14.66	$14.66	6.18%	$ 1,742
Granville	1,528	41,994	$13.64	$13.64	5.06%	$ 2,126
New Marlborough	1,510	43,025	$6.94	$6.94	8.70%	$ 3,742
Richmond	1,402	58,824	$9.88	$9.88	7.32%	$ 4,306
Egremont	1,374	39,823	$6.26	$6.26	9.23%	$ 3,677
West Stockbridge	1,329	91,260	$9.62	$9.62	4.69%	$ 4,281
Pelham	1,266	55,151	$16.97	$16.97	6.35%	$ 3,504
Royalston	1,261	29,975
Chilmark	1,235	103,896
Chester	1,220	30,530	$18.06	$18.06	7.79%	$ 2,377
Blandford	1,210	35,998	$11.71	$11.71	5.98%	$ 2,154
Petersham	1,183	46,952	$14.49	$14.49	5.87%	$ 2,758
Worthington	1,183	33,292	$13.79	$13.79	8.77%	$ 2,920
Charlemont	1,181	29,058	$18.30	$18.30	8.33%	$ 2,422
Chesterfield	1,175	25,075	$15.52	$15.52	12.40%	$ 3,109
Monterey	1,085	49,509	$6.44	$6.44	8.34%	$ 4,128
New Salem	1,008	30,227	$13.58	$13.58	7.82%	$ 2,364
New Braintree	990	46,509	$14.86	$14.86	5.18%	$ 2,409
Sandisfield	982	29,501	$9.02	$9.02	9.49%	$ 2,801
Goshen	947	18,585	$13.99	$13.99	17.06%	$ 3,171
Wendell	921	22,900
Cummington	818	64,869	$12.76	$12.76	3.80%	$ 2,465
Windsor	818	36,407	$11.34	$11.34	5.52%	$ 2,008
Montgomery	818	39,782	$11.34	$11.34	5.42%	$ 2,157
Peru	803	26,340	$15.95	$15.95	8.82%	$ 2,322
Warwick	780	28,036	$17.78	$17.78	9.13%	$ 2,559
Hancock	746	21,374	$2.69	$2.69	4.42%	$ 944
Leyden	734	50,507	$15.28	$15.28	4.68%	$ 2,365
Heath	721	18,488	$18.81	$18.81	15.93%	$ 2,945
Florida	681	24,226	$7.77	$7.77	4.13%	$ 1,001
Savoy	646	33,237	$16.62	$16.62	6.64%	$ 2,208
Plainfield	629	32,224	$18.48	$18.48	8.96%	$ 2,888
Washington	497	34,793	$14.16	$14.16	9.36%	$ 3,258
Alford	483	84,482	$4.95	$4.95	4.47%	$ 3,772
Tolland	467	32,214	$7.47	$7.47	11.39%	$ 3,669
Aquinnah	444	65,191	$6.76	$6.76	22.22%	$ 14,484
Rowe	421	35,473	$5.14	$5.14	2.40%	$ 850
Tyringham	421	41,074
Middlefield	388	61,059	$18.24	$18.24	5.93%	$ 3,618
Hawley	354	25,763	$16.35	$16.35	10.04%	$ 2,587
New Ashford	249	34,807	$5.66	$5.66	3.67%	$ 1,276
Mount Washington	157	74,433	$6.08	$6.08	6.11%	$ 4,548
Monroe	115	9,930	$8.99	$8.99	14.01%	$ 1,392
Gosnold	64	14,063

Boston tax rate comparisons to Fiscal 2024

A frequently asked question is: How much did Boston FY 25 tax bills change in general from FY24? There are many different quantitative approaches to this question. Here are five of them:

1. The median residential tax bill change (the level such that half of bills went up more and half went up less) was 9.3% (10.5% for owner-occupied single family homes).
2. The unweighted average residential tax bill change (the average of the percentage changes for each of the individual tax bills) was 11.6%.
3. The weighted average change, that is, the change in the total of the tax bills of all the residential properties was 9.7%.
4. The total change in the residential tax levy from the city’s tax recap sheets which was 9.2% (excluding the portion of the levy attributable to new growth in valuation — see levy change tab in this spreadsheet).
5. The tax bill for an owner-occupied single family home of average value in FY25 was 9.5% higher than the tax bill for an owner-occupied single family home of average value in FY24.

The five answers involve different comparison sets: For the first three approaches, the comparison set used is the 151,710 “class 1” residential properties that were present in both years, did not change land use, and had non-zero assessed value in both years. This set excludes 2,026 or 1.3% of the “class 1” properties that were on the list in FY2025; it also excludes 2,952 multiple use properties. For the fourth approach, the set is all properties. For the fifth approach the set in each year is all owner-occupied single family homes.

Patterns of change

Commercial property value declines

Before focusing attention on the residential bill variability driven by revaluation, we document the commercial value decline that has been heavily discussed elsewhere: The majority of commercial properties declined in value city wide, but especially in the downtown zip codes (02108 through 02118 and 02215). However, many commercial properties did show increases. The chart below includes all zip codes with commercial properties. (The number of properties in each zip code is shown next to each zip code.)

Percentages of commercial properties experiencing valuation percentage changes with defined ranges, FY24 to FY25 by zip code

The decline in commercial property values covered most categories of property including all grades of office space. The only categories in which the majority of properties saw increases were hotels, garages, parking lots, and vacant land.

Percentages of commercial properties experiencing valuation percentage changes with defined ranges, FY24 to FY25 by property type (with property counts by type).

Large residential valuation shifts

2025 is a certification or “revaluation” year for Boston and residential values have, in fact, shifted more, both up and down, than in a typical year. By statute and pursuant to department of revenue regulations and DLS guidelines every community in Massachusetts is required to adjust valuations every year based on market trends, but every five years, communities must seek certification from the Division of Local Services that they are assessing properties at full and fair valuation. This certification requires a deeper review and valuations may change more as a result.

The five-year certification review is conducted by BLA staff to ensure the proposed values were derived utilizing a methodology based on generally accepted mass appraisal practices, are supported with current market evidence, and are uniformly and equitably applied to all property. The data quality, all cost and depreciation tables, and land schedules will be reviewed for all real property. In addition, income producing property will be reviewed for income and expense analysis, development of the economic rent schedules, capitalization rates and correlation of the values derived from two appraisal approaches.

Certification Standards, Bureau of Local Assessment Informational Guideline Release 24-13

The 2025 Boston revaluation did result in shifts. The chart below compares the number of residential properties experiencing large value changes in FY24 and FY25. In both years, most residential properties experienced valuation changes of 0% to 10%, but in FY25 there were many more properties with changes outside that range: 35,627 (24%) saw their valuations go down and 21,002 (14%) saw their valuations go up by over 10%.

Count of residential properties by percentage change in valuation, FY23-FY24 and FY24-FY25

Within every zip code there was substantial variation in residential property valuations. In every zip code, there was a substantial group of properties that saw valuation decreases and in most zip codes, there was a substantial group of properties with valuation increases over 10% and many properties with increases over 20%.

Percentages of residential properties experiencing valuation percentage changes with defined ranges, FY24 to FY25 by zip code

Value changes by neighborhood and property type

This section looks in more depth at patterns of residential valuation change by neighborhood and property type. The most discernible trend in valuations is softness in the downtown condominium market, but what is ultimately most striking is the high variability even within single neighborhoods and property types.

The chart below shows the median increase in residential property values within zip code. The central Boston zip codes, 02108 through 02118 and 02215, show median valuation changes mostly under 2%, while the outer neighborhoods experience median valuation growth of 3 to 5%. 02210, the seaport, had healthy value growth, more like the other neighborhoods. The City of Boston publishes a zip code map here.

Median change in assessed value for residential properties, FY24 to FY25, by zip code

There also variations by property type. Condominiums, which constitute almost half (47%) of the residential properties in city, showed less assessed value growth than the other other major categories — single, two, and three family homes. Larger apartment buildings are generally down. Note that in the chart below, the first four property types add up to 87% of the individual properties in the city. The other categories are each only 1 or 2% of the individual properties. Additional, less numerous property categories are excluded from the chart.

Median change in assessed value for residential properties, FY24 to FY25, by major property type

Softness in the downtown condominium market (discussed in the real estate trade press) apparently drove much of the neighborhood variation. As the chart below shows, condo valuation growth was weakest in the central Boston zip codes (02108 through 02118 and 02215). In these zip codes, condominiums constitute 89% of the individual properties and dominate the valuation changes. (In all other zip codes together, condos only constitute 37% of the properties.)

Median change in assessed value for condo residence properties, FY24 to FY25, by zip code

Excluding condominiums, the variation in valuation growth was more modest and less patterned across neighborhoods, as shown in the chart below which combines single family with two and three family residences. (The patterns are similar for single vs. two/three family; for separated analysis, see this SF spreadsheet and this 2F/3F spreadsheet.)

Median change in assessed value for single/2F/3F family properties, FY24 to FY25, by zip code

The analysis above shows neighborhood and property type variations in valuation, but what is more striking is that even analyzing property classes in a single neighborhood, there is substantial variation. Focusing on just a single neighborhood, Brighton (02135), within most classes of property, many properties had decreases and many had substantial increases.

Brighton 02135: Percentages of residential properties experiencing valuation percentage changes with defined ranges, FY24 to FY25 by property type

Wide variation in residential tax bill increases

As changes in residential valuations vary, so changes in tax bills vary. However, the variation in change for residential tax bills is greater than the variation in change in assessed value because of the residential exemption. The residential exemption was $331,241 in FY24 and is $344,060 in FY25. If a taxpayer had a property with a value $50,000 over the exemption in FY2024 ($381,241), but their value increased to $100,000 over the exemption in FY2025 ($444,060), their taxes would double, even though their valuation only went up by 16%. They could similarly experience a dramatic decrease. The exemption leverages change most for the lowest value properties.

The next two illustration pairs array residential properties according to their percentage tax bill increase from FY24 to 25 — first for all residential then for owner-occupied.

Boston residential properties arrayed by FY24-FY25 tax bill increase
(vertical axis is % increase; horizontal access is percentile among properties)

The next chart analyzes the properties arrayed in the graphic above into groups according to the effect of the tax shift proposal on their tax bill rates and tax bill change.

Residential properties classified by effect of the tax shift proposal

Effect of tax shift proposal on bill increase	Count	Share	Average FY25 Bill	Average* FY25 Bill Increase	Average* FY25 Bill Increase with shift
Deeper cut	15,173	10%	$5,372.42	-8.6%	-13.0%
Increase becomes a cut	19,776	13%	$10,335.17	2.9%	-2.0%
Lowered from below 10% to further below	47,121	31%	$9,488.83	7.4%	2.3%
Lowered from above to below 10%	33,562	22%	$8,965.59	12.3%	7.0%
Remain above 10%	36,078	24%	$6,824.26	29.6%	23.4%
Grand Total	151,710	100%	$8,438.05	11.6%	6.3%

Owner-occupied residential properties arrayed by FY24-FY25 tax bill increase
(vertical axis is % increase; horizontal access is percentile among owner-occupied properties)

Owner-occupied residential properties classified by effect of the tax shift proposal

Effect of tax shift proposal on bill increase	Count	Share	Average FY25 Bill	Average* FY25 Bill Increase	Average* FY25 Bill Increase with shift
Deeper cut	11,621	15%	$4,214.40	-9.6%	-13.9%
Increase becomes a cut	9,628	13%	$6,755.24	2.8%	-2.1%
Lowered from below 10% to further below	15,253	20%	$8,361.17	7.7%	2.6%
Lowered from above to below 10%	16,213	21%	$7,083.47	12.4%	7.1%
Remain above 10%	23,551	31%	$5,277.72	32.1%	25.8%
Grand Total	76,266	100%	$6,302.78	13.0%	7.6%

Where are tax bill shifts greatest?

The only strong neighborhood pattern that emerges is that noted already for valuations — downtown neighborhoods saw lesser increases. The two charts below show the median tax bill change by zip code for non-owner-occupied properties (no exemption) and owner-occupied properties (with exemption). Inspecting the first chart, one sees that most of the downtown zip codes have median tax bill changes of 6.2%. This reflects the 6.2% increase in the tax rate from FY24 to FY25 applied to a median group of non-owner-occupied residential properties that have no change in assessed value. In some cases, this reflects condo parking spaces which are classified as residential and saw no change in valuation. In the rest of the city, the tax bills go up by 7 to 12% — so the overall range of median tax bill increases by zip code is from 6 to 12%, similar in span to the valuation changes by zip code shown further above which range from 0 to 5%. In the second chart, owner-occupied increases vary more widely from 4 to over 14% due to the leverage of the residential exemption.

Non-owner-occupied residential properties — median change in tax bill, FY24 to FY25, by zip code

Owner-occupied properties — median change in tax bill, FY24 to FY25, by zip code

The bills with the largest percentage increases tend to draw the most concern. These are likely to occur for owner-occupied properties that are of low value — these are the properties that have the largest leverage of change due to the residential exemption. The chart below shows the counts and average values of different property types in FY25 in Boston. The chart highlights the dominance of four property types and shows that the average values for each of those types are not as different as one might expect.

FY25 Class 1 Residential Properties by type and Owner-Occupancy

Property type	Not O-O Count	O-O Count	Not O-O Average value	O-O Average value
101–SINGLE FAM DWELLING	5,245	25,189	$1,044,030	$834,278
102–RESIDENTIAL CONDO	37,168	36,212	$881,302	$872,809
104–TWO-FAM DWELLING	6,758	9,990	$963,246	$909,445
105–THREE-FAM DWELLING	8,369	4,886	$1,191,420	$1,127,704
111–APT 4-6 UNITS	2,131	379	$1,343,126	$1,234,150
Larger Multifamily	2,964	52	$4,362,921	$3,279,157
Other — land, condo parking,  etc.	14,325	67	$71,967	$1,256,252

Focusing on the four major property types identified above, the following graphic highlights the zip code and property type combinations with the highest share of 20%+ tax bill increases. Large percentage tax bill increases are most common among condos in the outlying zip codes, but the high value downtown properties have the largest absolute bill increases. The City of Boston publishes a zip code map here. All the increases shown in the chart are annual tax bill increases as opposed to quarterly bill increases.

Owner-occupied residential properties by major property type* and zip code:
(a) Percentage having annual tax bill increases over 20% from FY24 to FY25,
(b) Average FY25 value of those with FY24 to FY25 tax bill increases over 20% (in millions)
(c) Average bill increase per unit of those with FY24 to FY25 tax bill increases over 20%.

Are the changes more than should be expected?

In a revaluation year, relative change is to be expected and the spread of relative change in this revaluation is less than in the last revaluation. The first chart below is a histogram of the percentage changes in assessed value for single family, two family, three family, and condominium residences. Of the 132,175 such properties that are present in both years, the chart excludes 0.6% or 836 outlier properties that differ by more than 30% from the unweighted mean change, which was 3.9%. Almost half of those excluded that are single, two, and three family properties do match by property ID to recent building permits, suggesting either substantial improvement or in a few cases decline due to a fire. However, it is hard to rely on building permit match alone as a mechanism of exclusion because the building permit database does not appear to consistently match to property id for condominium units, the most numerous property class (either that or there are only a handful of building permits pulled for condominium units). We exclude all 30%+ outliers (only 0.6% of the total) assuming that there is some special story about each of them. Computations for this section are here.

Distribution of properties by change in assessed value, FY24 to FY25, major residential property types

This distribution of change appears to have been wider in the last revaluation which occurred from FY20 to FY21. The FY21 revaluation was as of January 1, 2020, so it is based on pre-COVID sales data, although the actual property valuation process occurred through the early COVID months. As a way of comparing the dispersion in the current valuation to the prior valuation, the table below shows the standard deviation in valuation change by property type and zip code. The same 30% rule is used to exclude outliers from the FY20 to FY21 change comparison, but the rule does exclude more properties — the last valuation had more large outliers (1.4%). As the table shows, it also had higher standard deviations in every zip code and property type and in most combinations of zip code and property type. The standard deviations were generally greater (redder in the color scheme) in FY21 than in the current FY25 year.

Standard Deviations of Assessed Value Percentage by Change Zip Code and Property Type
— prior (FY20-21) compared to current valuation (FY24-25). Type 101, single family; type 102, condominiums; type 104, two family; type 105, three family.

As another metric of deviation which points to the same conclusion — FY25 may not be an unusual valuation year — the chart below shows the percentage of assessed value changes deviating more than 10 percentage points from the mean for each zip code and property type.

Share of Assessed Value Percentage Changes > 10 percentage points from mean
by Zip Code and Property Type — current vs prior revaluation year. Type 101, single family; type 102, condominiums; type 104, two family; type 105, three family.

It should be noted that property values for the 4 property types in the charts were generally rising faster through the last revaluation, with an unweighted average valuation increase of 9.5% versus 3.9% this year. This does appear to contribute to wider variation in that revaluation period, as the zip/type cells with the largest variation in FY21 tend to be the ones with highest mean valuation change. This is shown on the stddev tab in the computations spreadsheet. It’s not obvious whether or how to normalize for this difference in change rate. Because we are working with percentage changes, already scaled, it does not make sense to scale the standard deviation by the mean, computing a so-called “coefficient of variation.” Since our goal is to understand how wide the variation in taxpayer experience of change was, it probably does make most sense to view the standard deviations as we have presented them, without further normalization.

Resources

• Boston valuations for FY24 and FY25 in MSAccess format with computations (>602MB)
• Spreadsheet with change analysis, including FY24 and FY25 valuations and tax bills with and without shifts.