The CPA surcharge shows up as a line item in the table on the right side of a Boston property tax bill. It’s a small number, and the way the City reaches it is worth knowing.
What it funds and when it started
In November 2016, Boston voters approved the Community Preservation Act by voting yes on Ballot Question 5. The City finances the resulting Community Preservation Fund in part with a 1% property tax-based surcharge on residential and business property tax bills, beginning in July 2017, and the line may appear on quarterly bills beginning in fiscal year 2018. Since 2018 the money has gone to historic preservation, affordable housing, open space and recreation. By law the City must form a Community Preservation Committee, which identifies needs and recommends allocations, and any project needs both that recommendation and an appropriation by the City.
The calculation
Assessing starts by deducting $100,000 from the value of your property. It recalculates the tax on the remaining value, then applies your residential exemption and any personal exemptions. Whatever tax is left after those steps is the revised net tax. The surcharge is 1% of that figure, divided over your four quarterly tax bills. For first and second quarter bills the surcharge is estimated using your revised net tax from the prior year.
The City’s worked example
The City publishes a table for fiscal year 2026 with three columns. A residential property with the residential exemption: value $600,000, less the $100,000 deduction, a recalculated value of $500,000, a recalculated tax of $6,200, less the residential exemption of $4,353.74, leaving a revised net tax of $1,846.26 and a surcharge of $18.46. The same property with a personal exemption as well: a further $1,000 comes off, the revised net tax is $846.26 and the surcharge is $8.46. A commercial property at the same value: the recalculated tax is $13,480, no residential or personal exemption applies, and the surcharge is $134.80.
Why the residential exemption matters twice
The exemption you file for to cut your property tax also cuts your CPA surcharge, because it comes off before the surcharge is figured. That’s worth knowing if you’ve never filed for the residential exemption. The surcharge saving is a few dollars, but the residential exemption behind it is the bigger deduction on the bill, and that one is worth filing for.
When there’s no surcharge
Residential and commercial owners may be assessed a surcharge unless the revised net tax is $0, or the property receives an exemption from the surcharge. A revised net tax of $0 happens when the $100,000 deduction and the exemptions take the recalculated tax down to nothing.
The surcharge exemption
There is a separate exemption for low-income property owners and for low- and moderate-income senior owners. It requires an application to the Assessing Department. Applications are available beginning in January of each fiscal year and must be filed by April 1 of that fiscal year. Eligibility uses income limits the City publishes by household size. For fiscal year 2026 the limits for a one-person household were $90,104 for non-seniors and $112,630 for seniors, and a four-person non-senior household came in at $128,720. Eligibility for fiscal year 2026 was based on 2024 income. Applicants may be asked to provide federal and state income tax returns.
How household income is measured
The City’s formula is gross household income minus a dependent deduction minus a medical expense deduction. Gross household income counts income from all sources and all household members who were 18 years of age or older and not full-time students in the relevant calendar year. The dependent deduction is the number of dependents excluding a spouse, multiplied by an allowance per dependent set by state regulation. The medical expense deduction is out-of-pocket medical spending above a share of gross household income, and out-of-pocket includes health insurance premiums, payments to providers, diagnostic tests, prescription drugs and medical equipment that no insurer or employer reimbursed.
What to do with this
If you own in Boston, pull up a recent bill and find the line. If it’s there and it looks wrong, questions about the calculation go to the Taxpayer Referral and Assistance Center, and billing questions go to the Collecting Division. If you’re not seeing a residential exemption on the bill, that’s the bigger thing to check, and I’m happy to walk through it with you. Diana Kim, REALTOR®, eXp Realty.
Questions
Common questions
What is the CPA surcharge in Boston?
A 1% property tax-based surcharge on residential and business property tax bills that finances the City's Community Preservation Fund. Boston voters approved the Community Preservation Act in November 2016 on Ballot Question 5, and the surcharge began in July 2017.
Is the CPA surcharge 1% of my property tax?
No. It's 1% of the revised net tax. The City first deducts $100,000 from your property's value, recalculates the tax, and applies your residential exemption and any personal exemptions. The surcharge is 1% of what remains.
How is the surcharge billed?
It is divided over your four quarterly tax bills and shows up as a line item in the table on the right side of the bill. For first and second quarter bills it's estimated using the prior year's revised net tax.
Can I be exempt from the CPA surcharge?
Yes. There's an exemption for low-income owners and for low- and moderate-income senior owners, by application to the Assessing Department. Applications are available in January of each fiscal year and are due by April 1 of that fiscal year.
What if my revised net tax is zero?
Then there's no surcharge. The City states that owners may be assessed a surcharge unless the revised net tax is $0 or the property receives an exemption from the surcharge.
Written by Diana Yeji Kim — REALTOR® at eXp Realty, serving Greater Boston in English, Korean, and Japanese.
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