Philadelphia, PA Zoning Overlays & Bonuses: Density Bonus Law (2026)
Key Facts
- Eligible districts
- RM-1, CMX-1, CMX-2, CMX-2.5 only
- Moderate-income bonus
- 25% more dwelling units
- Low-income bonus
- 50% more dwelling units
- On-site set-aside
- 10% of units, rounded up
- Affordability term
- 50 years minimum
- In-lieu fee
- $13,600 moderate / $17,700 low per unit
- Payment-in-lieu minimum
- 10+ dwelling units required
Summary
Philadelphia's Zoning Code lets developers in the RM-1, CMX-1, CMX-2, and CMX-2.5 districts build more dwelling units than the base zoning allows by providing affordable housing. Setting aside at least 10% of units as affordable earns a 25% density increase for moderate-income units or 50% for low-income units under § 14-702(7) and Table 14-702-5.
(2.2) Eligibility for Dwelling Unit Density Bonuses. In order to be eligible for any dwelling unit density bonuses pursuant to this section, the property must be in an RM-1, CMX-1, CMX-2, or CMX-2.5 zoning district. ... (.1) At least ten percent (10%) of residential dwelling units (rounded up, if fractional) shall be provided and maintained as affordable... Table 14-702-5: Mixed Income Housing Bonus – Housing Unit Density Bonuses (RM-1, CMX-1, CMX-2, or CMX-2.5 only): Mixed Income Housing Moderate Income: 25% increase in units permitted; Low Income: 50% increase in units permitted.
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: 2026 Code: Electronic version of The Philadelphia Code and Home Rule Charter is current through August 19, 2026).
Full Breakdown
5 zoning districts. 1) requires that at least ten percent (10%) of residential dwelling units, rounded up if fractional, be provided and maintained as affordable, using the affordability definitions in § 14-702(7)(a). Those units must be reasonably dispersed on-site, comparable in quality to market-rate units, and, for owner-occupied units, subject to a Department of Planning and Development right of first refusal on resale. 2) requires the affordability commitment to run for a term of not less than 50 years, secured by a recorded instrument in favor of the City in a form satisfactory to the Law Department.
Table 14-702-5 sets the payoff: a moderate-income project earns a 25% increase in permitted dwelling units, while a low-income project earns a 50% increase. 5 properties the in-lieu fee is calculated by multiplying the number of bonus-eligible dwelling units by $13,600 per unit for the moderate-income option or $17,700 per unit for the low-income option. 2) requires any density bonus calculation to round fractional units down to the nearest whole number, and bars stacking this bonus with itself, though it can combine with other, separately earned dwelling unit bonuses.
Violations & Fines
Under § 14-702(7)(d), the Department of Planning and Development must certify the applicant's acknowledgment of the mixed-income requirements before Licenses and Inspections can issue a zoning permit, and must certify that required payments were made or that an Affordable Building Plan is on file before a building permit issues. Developers who file an Affordable Building Plan acknowledge they are subject to penalties if the completed project fails to conform to that plan.
Frequently Asked Questions
Which Philadelphia zoning districts qualify for the dwelling unit density bonus?
How many extra units can a project earn?
Can a developer pay a fee instead of building affordable units?
How long must the affordable units stay affordable?
Sources & Official References
Other rules in Philadelphia
Compare Philadelphia to another location·View the Pennsylvania zoning overlays & bonuses overview
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