A second kitchen
is not a second unit.
For a DC row house owner thinking about a second unit, and for a buyer looking at a house sold as two. If you own a condo unit, the building's documents decide this, not the zoning.
Can I convert my DC row house into two units?
It depends on the zone, so look that up first. The RF-1 zone covers many of the city's row house blocks. There, a lot may hold two dwelling units. Both can be in the main house, or one can be in a carriage house or other accessory building. In the R zones, a lot gets one principal unit plus one accessory apartment, under conditions set in Subtitle U. The DC Zoning Map shows which zone your lot is in.
Can I add a third unit?
Not as a matter of course. In RF-1, only a building that existed before May 12, 1958 can hold more than two units. It gets there through Subtitle U, Chapter 3, a process that runs through the Board of Zoning Adjustment. RF-1 also does not allow an accessory apartment inside one of the two units.
What does the city need to see before the second unit is legal?
A building permit for the work, then a certificate of occupancy for a two-family house from the Department of Buildings. The construction code requires fire-rated walls and floors between the two units, so price that work before you price the rent. Renting the second unit then takes a Two-Family Rental license from the Department of Licensing and Consumer Protection, $219 for two years, and a registration with the Department of Housing and Community Development.
How many DC row houses are already two units?
6,676 row houses are recorded by the DC assessor as residential conversions, use code 024. 56% of them carry a homestead deduction, so the owner lives in one of the units. Recorded as two units is not the same as rented as two: many are sold and lived in as one house. The property record shows which one you are looking at.
Does a two-unit row house sell for more?
A little, against its assessment. Over the last two years, 385 fee simple row houses recorded as two units sold at a median 106.6% of their assessment, after 15 days. The other 3,185 sold at 102%, after 19 days. On a house assessed at $1M, that is $1,066,000 against $1,020,000. The record does not show what each conversion cost, or whether the second unit was rented.
| Recorded as two units | All other row houses | |
|---|---|---|
| Sales | 385 | 3,185 |
| Median sale price | $1,350,000 | $860,000 |
| Median sale, % of assessment | 106.6% | 102% |
| Median days on market | 15 | 19 |
| Median sale, % of first ask | 98% | 98.2% |
What if a tenant is living in the unit when I sell?
Then DC's tenant rights come with the sale. The Tenant Opportunity to Purchase Act can give a tenant notice and purchase rights before you sell to anyone else. Talk to a DC real estate attorney before you list, not after you have an offer.
Read next: the English basement and what renovation is worth.
Every closed sale on your block for 24 months, in two sections. No charge, no obligation.
Send me every sale on my blockSources. DC Municipal Regulations Title 11, Subtitle E §§ 300.1 and 302.1 to 302.3 (RF-1) and Subtitle D §§ 201.1 and 201.2 (R zones). DC Department of Buildings, Certificate of Occupancy. DC Department of Licensing and Consumer Protection, Housing Business. DC open data, CAMA residential and ITSPE (use code 024). BrightMLS closed sales of DC fee simple row houses in the two years to October 24, 2026.
This page explains rules and practice; it is not legal or tax advice. For a specific house, talk with a DC real estate attorney or a tax professional.