ADU rules in Prince George's County, MD
Yes. An ADU is a new dwelling unit and needs a building permit.
Maryland law required the county to allow ADUs on single-family detached lots by October 1, 2026.
The county's ADU law, CB-074-2026, was enacted September 29, 2026 and is reported to take effect November 16, 2026.
Rules last checked by a person on October 20, 2026. Guidance only; confirm with Prince George's County before you build.
Limits
| Size (state minimum) | Local rules must allow at least 75% of the house's size |
|---|---|
| Setbacks (state minimum) | No stricter than for other accessory structures |
| Parking (state minimum) | No extra space unless a parking study supports it |
Good to know
- CB-074-2026, the county's ADU law, was enacted September 29, 2026. The Council record lists November 16, 2026 as the effective date. Confirm the date and the final standards with DPIE before you design.
- Call 811 at least a few days before you dig footings or post holes. Utility locating is free.
- HOA covenants and deed restrictions can be stricter than city rules. Check yours before you build.
- Prince George's renamed its zones in 2022. If a plat or listing says R-55 or R-80, the lot is now RSF-65 or RSF-95.
Check your lot
Where to apply
Sources
- Prince George's County DPIE, What work is exempt from obtaining a permit?. Checked 2026-10-20.
A one-story detached accessory structure on one- and two-family dwelling properties with less than 150 square feet of floor space not designed or intended for occupation or habitation and limited to 1 accessory structure only per property... A retaining wal…
- Maryland Department of Planning, ADU FAQ for local governments (HB 1466, 2025). Checked 2026-10-20.
Local governments must authorize ADUs on lots with a single-family detached dwelling by October 1, 2026; allow ADUs up to 75% of the primary dwelling's size; apply setbacks no stricter than for accessory structures; and impose no extra parking unless a stud…
- Maryland ADU Guide, Prince George's County CB-074-2026 status (October 2026). Checked 2026-10-20.
CB-074-2026 was enacted September 29 [2026]... [it] establishes zoning standards consistent with Maryland's statewide ADU law... [The Council record lists an effective date of November 16, 2026; confirm with DPIE.]
- 44 CFR 59.1, definition of development (NFIP). Checked 2026-10-19.
Development means any man-made change to improved or unimproved real estate, including but not limited to buildings or other structures...
- 44 CFR 60.3, floodplain management criteria. Checked 2026-10-19.
Require permits for all proposed construction or other development in the community...