What's Required in Pittsburgh
- Under Zoning Code 912.08, ADUs are permitted only within an Accessory Dwelling Unit Overlay District.
- An ADU must be smaller than 800 square feet and accessory to a structure with one legal dwelling unit.
- Only one ADU is allowed per zoning lot, and the owner must reside on site.
- An ADU may not exceed two stories or 30 feet, and may not be leased for less than 30 days.
- A deed restriction must be recorded before the certificate of occupancy is issued.
- ADUs are exempt from the on-site parking requirements of Chapter 914.
- Building, electrical and mechanical permits come from PLI; plumbing permits come from the Allegheny County Health Department.
- Construction of a new dwelling needs a city General Contractor license or a PA Home Improvement Contractor registration.
Can You Build an ADU in Pittsburgh?
Not by right on most lots, as of October 2026. Pittsburgh's Zoning Code defines an accessory dwelling unit as a dwelling unit smaller than 800 square feet, accessory to a structure with a single legal dwelling unit, and Section 912.08 permits ADUs only within an Accessory Dwelling Unit Overlay District mapped by ordinance. That section dates from Ordinance 32-2018, and the city's own housing page says the 2018 overlay covered the single-family zoned portions of Garfield and was set to expire after two years. Check the Pittsburgh zoning map, or email [email protected], to see whether any overlay applies to your lot before you pay for drawings.
Change is pending. Council Bill 2025-1545 carries the Department of City Planning's ADU amendments, whose summary proposes ADUs by right as an accessory use to a residential use, no owner-occupancy requirement, two ADUs per residential lot, a 1,000 square foot maximum per ADU and up to 30 feet in height. Legistar shows a public hearing on 9/23/26 and a status of Held In Council, so none of that is law yet. Outside an overlay today, the planning department's zoning FAQ says even turning a single-family home into a two-family home is not automatic: setbacks, lot area and parking all have to work for that use on that lot.
Pittsburgh ADU Rules by Scenario
| What you are doing | City filing | Rule |
|---|---|---|
| ADU on a lot inside an ADU Overlay District | BDA with zoning and PLI review | Zoning 912.08 |
| ADU on a lot outside any ADU overlay | Not permitted by right today | Zoning 912.08; Bill 2025-1545 pending |
| Second ADU on the same lot | Not allowed under current code | 912.08.E.3: one per lot |
| ADU behind a house that is already a duplex | Not allowed under current code | 912.08.E.10 |
| Owner living elsewhere | Not allowed under current code | 912.08.E.4: owner resides on site |
| Plumbing for the new unit | ACHD plumbing plan and permit | ACHD fee schedule |
Where an overlay applies, Section 912.08 adds: only one ADU per zoning lot; the owner must reside on site; the ADU may not exceed two stories or 30 feet; no lease shorter than 30 days; no on-site parking requirement; and a deed restriction recorded before the certificate of occupancy binding current and future owners.
How Much Do ADU Permits Cost in Pittsburgh?
An ADU stacks several permits. PLI's 2026 residential base fee is $6.00 per $1,000 of construction value, minimum $130, plus a $4.50 state training fund fee, a $5.00 digital record retention fee and a technology fee ($5 when the base fee is $201 to $1,000). Zoning review is $1.00 per $1,000, minimum $50. Electrical and mechanical permits are each $141.50 at the minimum. ACHD charges $80 (0 to 5 fixtures) or $117 (6 to 50 fixtures) per plan plus $22 per fixture. A $60,000 basement conversion: building $360 + $14.50 = $374.50, zoning $60, electrical $141.50, mechanical $141.50, ACHD $80 + 5 fixtures = $190, total $907.50. A $150,000 detached unit: building $900 + $14.50 = $914.50, zoning $150, electrical $141.50, mechanical $141.50, ACHD $117 + 8 fixtures = $293, total $1,640.50. A Zoning Board of Adjustment hearing, if you need relief, is $400. Those are PLI's residential rates; its permitting page puts attached single- and two-family dwellings in the commercial category, where the minimum base fee is $605, so confirm which category the portal assigns your house.
Who Can Build It?
PLI requires a city General Contractor license for construction of new one- or two-family dwellings and for renovations at rental or investment property, and its licensing rules accept a Pennsylvania Home Improvement Contractor registration in place of that license. Electrical and mechanical work need city trade licenses.
How to Get a ADU Permit in Pittsburgh
Confirm the overlay
Check the zoning map or email [email protected]; outside an ADU overlay the unit is not permitted by right while Bill 2025-1545 is pending.
Design to Section 912.08
Keep the unit under 800 sq ft and within two stories or 30 ft, one per lot, with the owner living on site.
File the BDA and trade permits
Apply in OneStopPGH with drawings and the construction value; add electrical and mechanical permits and the ACHD plumbing plan.
Record the deed restriction
Record the deed restriction required by 912.08 before the certificate of occupancy can issue.
Inspections and occupancy
Pass PLI and ACHD inspections, then obtain the certificate of occupancy for the new unit.