A Dorchester three-family sat on the market for 90 days. Here's what the three households renting it would have paid to buy it together.
A three-family in Dorchester was listed on Zillow for $1,049,000 and sat on the market for 90 days before it went under contract in September. For those three months the most obvious buyers were the three households already living there, paying $2,800, $2,900 and $2,890 a month in rent, so we ran the numbers on what it would have cost them to buy the building together.
If each household took a third of the building, that's a $349,667 share and $34,967 down at 10%. At today's 30-year fixed rate of 7.40%, with property taxes after Boston's residential exemption, insurance, mortgage insurance and $233 a month set aside for water and upkeep, each household would pay $2,995 a month to own. Their rent averages $2,863, so in the first year owning costs only $132 a month more.
| Per household | 10% down | 20% down |
|---|---|---|
| Share of purchase price | $349,667 | $349,667 |
| Down payment | $34,967 | $69,933 |
| Mortgage | $314,700 | $279,733 |
| Principal and interest 7.40% 30-year fixed | $2,179 | $1,937 |
| Property tax After residential exemption | $240 | $240 |
| Insurance | $146 | $146 |
| PMI | $197 | $0 |
| Water and upkeep reserve | $233 | $233 |
| Monthly to own | $2,995 | $2,556 |
| Rent today | $2,863 | $2,863 |
| Rent minus owning | −$132 | +$307 |
That gap closes over time because the mortgage payment stays the same every year while rent keeps going up. With rent rising 2% a year (and taxes, insurance and upkeep rising 2% a year too, to keep the comparison fair), the difference drops to $87 in year two and $41 in year three, and by year four owning is the cheaper of the two.
| Year | Own, 10% down | Rent | Rent minus own | Own, 20% down | Rent minus own |
|---|---|---|---|---|---|
| 1 | $2,995 | $2,863 | −$132 | $2,556 | +$307 |
| 2 | $3,007 | $2,920 | −$87 | $2,569 | +$351 |
| 3 | $3,020 | $2,979 | −$41 | $2,581 | +$398 |
| 4 | $3,033 | $3,038 | +$5 | $2,594 | +$444 |
| 5 | $3,046 | $3,099 | +$53 | $2,607 | +$492 |
| Five-year total | $181,218 | $178,790 | −$2,428 | $154,890 | +$23,900 |
Over five years each household would pay $2,428 more to own than to rent, and in exchange they'd have paid $17,236 off their share of the mortgage, which is equity they keep whatever the market does. If the building also gains 3% in value each year, their share would be worth another $55,693, for $72,929 of equity in total, or $107,896 counting the down payment they put in, where a renter in the same unit would have nothing.
| Per household | 10% down | 20% down |
|---|---|---|
| Principal paid down | $17,236 | $15,321 |
| Share of appreciation at 3% a year | $55,693 | $55,693 |
| Equity built | $72,929 | $71,014 |
| Plus the down payment | $34,967 | $69,933 |
| Total equity | $107,896 | $140,947 |
With the monthly cost of owning this close to rent, the cash to close becomes the only financial barrier. The City of Boston built a program for exactly this. Its Co-Purchasing program lends each first-time buyer household that purchases a two- or three-family together money at 0% interest, not paid back until they sell, transfer or refinance. On a $349,667 share that covers $17,483 of the down payment (5% of the share) and $3,497 of closing costs, so a household that needs $38,464 to close would bring $17,484 of its own money. Split between a household of two, that's less than $10,000 each to own a unit in the city of Boston, at a monthly cost only slightly above rent.
| Per household | 10% down | 20% down |
|---|---|---|
| Down payment | $34,967 | $69,933 |
| Attorney and other closing costs About 1% | $3,497 | $3,497 |
| Total needed at closing | $38,464 | $73,430 |
| City loan toward the down payment 5% of share | −$17,483 | −$17,483 |
| City loan toward closing costs | −$3,497 | −$3,497 |
| Out of pocket | $17,484 | $52,450 |
A household that can put 20% down would pay $2,556 a month, which is $307 less than rent from the first month and $23,900 less over five years. That household needs $52,450 out of pocket even after the City's help, because the City's down payment loan tops out at 5% of the share. It's a higher barrier, and it shows how much the down payment moves the monthly cost.
The price, the rents and the rate on this building were all public, so the price was never what stopped these tenants from buying. The hard part is getting three households to walk through the questions that need to be asked upfront, with agreements that set out how they proceed when circumstances change. They also need a lender, an attorney and the landlord aligned. Restored Living takes a group from this idea to a closed purchase. If you want to see what your own building would cost to own, come to Before Next Lease, our co-buying session on Saturday, November 14 in Jamaica Plain.
Before Next Lease · Sat Nov 14 · Jamaica Plain
How we ran these numbers: property is 46 Theodore Street, Dorchester, listed at $1,049,000 (Zillow); rents treated as equal at $2,863 per unit; 7.40% 30-year fixed, the Freddie Mac average for the week of October 8, 2026; Boston's FY2026 residential tax rate of $12.40 per $1,000 less the $4,353.74 residential exemption; insurance at 0.5% of price a year; PMI at 0.75% of the loan a year at 10% down; a $700 a month water and upkeep reserve for the building; rent, taxes, insurance and the reserve rising 2% a year; appreciation of 3% a year. City loan terms from the City of Boston Co-Purchasing Housing Pilot and its Financial Assistance Guidelines: 0% interest, deferred until sale, transfer or refinance; down payment assistance up to 5% of the household's share plus eligible closing costs, capped at $50,000 per household at or below 100% of AMI ($137,200 for two people) and $35,000 up to 135% ($185,200); at least 1.5% of the household's share from its own funds; first-time buyers only; CHAPA-approved courses required. All figures are estimates, not tax or investment advice.