Pennsylvania: Philadelphia exempts small homes from stormwater rules and widens its maximum release-rate zones
Since July 1, 2026, one- and two-family projects disturbing under one acre are exempt from Philadelphia's post-construction stormwater rules, release-rate zones are larger, and sites of 5,000 square feet or more need approved erosion plans. Guidance Manual 3.4 took effect the same day.
According to the Philadelphia Water Department's Development Services newsletters of April, May, June and July 2026, amendments to the City's Stormwater Regulations took effect on July 1, 2026, together with version 3.4 of the Stormwater Management Guidance Manual. The July 2026 newsletter states that three changes are "effective today": an exemption from post-construction stormwater management for small residential projects, an expansion of the Public Health and Safety ("PHS") Release Rate areas, and a requirement that erosion and sediment control plans be approved for projects proposing earth disturbance of 5,000 square feet or more.
Philadelphia Water Department, Stormwater Regulations (amendments effective July 1, 2026) and Stormwater Management Guidance Manual v3.4; PWD Development Services Newsletters (April, May, June, July 2026)