Figures current as of October 15, 2026. Watertown sets its fiscal 2027 tax rate this winter, so the tax and market figures are due for a review in January 2027, and the lease and tax rules in October 2027.
Renting out your Watertown condo after you move, instead of selling it, changes two numbers the day you become a landlord. The property tax bill loses the residential exemption, and if you're buying again, every dollar of equity left in the unit is a dollar you borrow at today's mortgage rate. Here's the rent or sell arithmetic on a typical two-bedroom, what Massachusetts requires before the first lease, and the test that decides it.
- Watertown's fiscal 2026 residential tax rate is $12.20 per $1,000 of assessed value, and its residential exemption takes $324,715 off an owner-occupied home's assessment, a tax savings of $3,961.52, per the City of Watertown's published tax rates.
- Watertown grants the residential exemption only to an owner who owns and occupies the home as their domicile as of January 1, and removes it once those qualifications are no longer met, per the city's residential exemption page.
- Freddie Mac's average 30-year fixed mortgage rate was 7.40 percent as of October 8, 2026, up from 6.30 percent a year earlier, per the Primary Mortgage Market Survey.
- Since August 1, 2025, a Massachusetts landlord who hires a broker to lease a unit pays that broker and cannot require the tenant to pay the fee or add it to the rent, per the Commonwealth's rental broker fee FAQ.
- A two-bedroom, 1,070 square foot condo at 48 Bigelow Ave. in Watertown sold for $615,000 in the week ending September 13, 2026, per Watertown News.
What happens to your Watertown tax bill when you rent out your condo?
It rises by the full residential exemption, $3,961.52 at fiscal 2026 rates, because Watertown only grants the exemption on a home its owner lives in as their domicile. The exemption is a fixed $324,715 off the assessment, so the savings are the same dollar figure on almost every condo in the city, whatever the unit is worth.
On a two-bedroom assessed at $615,000, about what the Bigelow Ave. unit sold for in September, the fiscal 2026 bill at $12.20 per $1,000 is $3,541 while you live there and $7,503 once you rent it out. That's more than double, and it lands before you've collected a dollar of rent.
Eligibility turns on January 1. Massachusetts assesses property as of January 1 for the fiscal year that starts the following July, so if you're out of the unit by January 1, 2027, expect the exemption to come off for fiscal 2028, which begins July 1, 2027. The fiscal 2027 rate gets set this winter, so the exact dollar figure will move.
Don't wait for the assessors to notice. The city removes the exemption once you no longer qualify, so tell the Assessors' Office when your domicile changes and budget the full bill from the first year you're gone.
What does a Watertown two-bedroom earn as a rental?
In our worked example, about $23,700 a year before the mortgage, which is under 4 percent of the unit's value once the full tax bill and the costs of owning a rental come out.
The rent is the strong part. Rentometer's current figure for a Watertown two-bedroom was $3,548 a month as of its May 18, 2026 update, per Rentometer's Watertown rent data, so the example uses $3,500. The weak part is everything else: the tax bill without the exemption, the condo fee, a reserve for repairs and insurance, and a month of rent a year for vacancy and leasing.
That leasing line is new money for a lot of owners. Since August 1, 2025, the landlord who hires the broker pays the broker, and Massachusetts doesn't let you pass the fee to the tenant or fold it into the rent. Budget it every time the unit turns over.
Line | Per year |
|---|---|
Rent at $3,500 a month | $42,000 |
Less vacancy and leasing, one month's rent | $3,500 |
Less property tax at $12.20 per $1,000, no residential exemption | $7,503 |
Less condo fee at $400 a month | $4,800 |
Less insurance, repairs and reserves | $2,500 |
Net before the mortgage | $23,697 |
Less the payment on a $416,000, 30-year loan at 3.0 percent taken in 2021 | $21,046 |
Cash left after the mortgage | $2,651 |
Loan principal paid down over the same 12 months | $10,190 |
The condo fee, the reserve and the loan are assumptions, so swap in your own. The tax line isn't. On a 3.0 percent loan the rent covers everything with about $2,650 to spare, plus about $10,200 of principal the tenant pays down for you.
Does keeping your Watertown condo as a rental beat selling it?
If you're financing your next home, only when you expect the condo to keep appreciating, because the equity left in it earns about 5.2 percent in this example while the same money put toward the new mortgage saves 7.40 percent.
Here's the test. Add the cash flow and the principal paydown, about $12,800, and divide by your equity. With roughly $366,500 still owed, the example owner has about $248,500 of equity, so the rental returns about 5.2 percent a year before appreciation and before income tax.
Now the alternative. Sell, and that $248,500 goes into the down payment on the next house, which is $248,500 you don't borrow at the 7.40 percent Freddie Mac reported on October 8. That's about $18,400 a year of interest you never pay. The rental has to make up roughly $5,500 a year through appreciation, about 0.9 percent of the unit's value, just to tie.
Selling costs narrow that gap, since you don't take home the full $248,500. Income tax moves it in both directions, which is your CPA's job to run. And the 3.0 percent loan is the best thing about keeping the condo, but it only helps on the $366,500 you owe, not on the $248,500 you own.
Renting also starts a clock. IRS Publication 523, the 2025 edition, lets you exclude up to $250,000 of gain, or $500,000 for a married couple filing jointly, if you owned the home and lived in it for at least 24 months of the five years before the sale.
The rental years after you move out don't count against you, so a sale within three years of leaving keeps the exclusion. Gain from depreciation after May 6, 1997 is taxed either way, and we walked through that math in our post on selling a Watertown two-family you live in.
What does Massachusetts require before you lease your condo?
Lead paint paperwork if the building predates 1978, lead-safe conditions if a child under six moves in, and a broker fee that's yours to pay if you hire the broker.
For a home built before 1978, you give the tenant the Tenant Lead Law Notification and both of you sign a Tenant Certification Form before the rental agreement, along with any Letter of Compliance or Letter of Interim Control the unit has, per the Department of Public Health's tenant notification guidance. If your condo sits in a converted two-family or any building from before 1978, check the year first.
If a child under six lives in the unit, the Lead Law says the owner must remove or cover lead paint hazards, and you can't refuse to rent to someone because of lead paint, which the state calls illegal discrimination, per the Department of Public Health's fact sheet for property owners. If the unit has never been inspected, find out what deleading would involve before you list, not after a family applies.
Then the paperwork that isn't state law but bites anyway. Read your condo's master deed, bylaws and rules for leasing limits and minimum lease terms, and tell your insurer the unit is rented, since a policy written for an owner-occupant covers a different risk.
What this means if you're moving out of a Watertown condo this fall or winter
If you bought in 2020 or 2021 on a 3 percent loan and you're buying a single-family in Waltham, Belmont or Newton with a new mortgage, the math above is your math. Unless you're confident the condo will appreciate faster than about 1 percent a year, selling and putting the equity into the new house usually wins, and selling inside three years keeps the gain tax-free.
If you're leaving for a job posting and plan to come back in two years, renting is the stronger play. You keep the unit, the tenant covers most of the carrying cost, and you can apply for the exemption again once you're living there on a January 1.
If you own the condo outright, the hurdle is different, because there's no new mortgage to pay down. Compare the roughly 3.9 percent the example unit earns on its full value, before income tax, with what the cash would earn somewhere else, and remember the rental comes with a landlord's job.
Watch the calendar, too. If your move lands near the new year, being out before January 1, 2027 or after it is worth about a year of the exemption, roughly $3,962 at fiscal 2026 rates. If the closing on your next home is flexible, ask which side of that date it falls on.
Frequently asked questions about renting out or selling a Watertown condo
Do I lose Watertown's residential exemption if I rent out my condo?
Yes, Watertown grants the residential exemption only to an owner who owns and occupies the home as their domicile as of January 1, so a condo you've moved out of and rented loses it, and it was worth $3,961.52 a year at fiscal 2026 rates.
How much is Watertown's residential exemption worth?
In fiscal 2026, Watertown's residential exemption took $324,715 off the assessed value of an owner-occupied home, which saved $3,961.52 at the $12.20 per $1,000 residential tax rate.
Is it better to rent out or sell my Watertown condo when I move?
If you're financing your next home at around 7.40 percent, a $615,000 Watertown two-bedroom renting at $3,500 a month earns about 5.2 percent on its equity in our worked example, so keeping it as a rental only wins if it appreciates by roughly 0.9 percent a year or more.
Who pays the broker fee when I rent out my condo in Massachusetts?
Since August 1, 2025, the landlord pays the broker fee whenever the landlord hired the broker, and Massachusetts doesn't allow that fee to be passed to the tenant or added to the rent.
Can I rent out my condo and still avoid capital gains tax when I sell?
Yes, if you owned and lived in the condo for at least 24 months of the five years before the sale, which in practice means selling within about three years of moving out, though gain from depreciation taken on the rental after May 6, 1997 is still taxable.
What lead paint paperwork do I need to rent out a Watertown condo built before 1978?
Before the lease is signed, you give the tenant the Tenant Lead Law Notification, both of you sign the Tenant Certification Form, and you hand over any Letter of Compliance or Letter of Interim Control the unit has.
The next step if you're deciding whether to rent or sell your Watertown condo
Ask for a rent or sell analysis before you pick a move-out date. PH Realty Group prices your unit both ways, what it would lease for this winter and what it would sell for now, and lays the full tax bill, the leasing cost and your loan next to each, so you can see which side of the 7.40 percent line you're on.
If you decide to rent, our leasing service for Watertown landlords handles the pricing and the tenant search, and property management for owners who have moved away covers the years you're not around. If you decide to sell, start with a current valuation of your Watertown condo. Ethan Piani-Hohmann, PH Realty Group, (781) 879-0863, [email protected].
