Accessory Dwelling Units (ADUs) in Philadelphia
When a second, smaller home on a lot is allowed — and when it needs relief.
What is an accessory dwelling unit (ADU)?
An ADU is a smaller, secondary home on the same lot as a main house — a converted garage, a basement or attic unit, or a small backyard structure. ADUs add housing and rental income, which is why they have become a popular topic, but whether you can build one depends entirely on local zoning.
Are ADUs allowed in Philadelphia?
The Philadelphia Zoning Code limits where a second dwelling unit is permitted, and in many residential districts adding one is not automatically allowed. Whether an ADU is possible on a given lot depends on the property's zoning district, and a project that is not permitted by right generally needs a variance.
What a project involves
Beyond zoning, an ADU triggers permitting and building-code requirements. Confirming the zoning path first — by right versus variance — tells you whether the project is straightforward or a hearing case.
How Nochumson P.C. helps
Nochumson P.C. advises owners and developers on whether an ADU is feasible and secures any needed relief. Contact us to explore an ADU.
Related articles:
- Floor Area Ratio (FAR), Explained
- By-Right vs. Variance Development in Philadelphia
- Philadelphia Zoning Permits: What You Need
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