Lehigh County, PA Environmental Rules: Flood Zones (2026)

Pennsylvania's Floodplain Management Act (Act 166 of 1978), codified at 32 P.S. §679.101 - 679.601, requires every municipality with FEMA-identified flood-prone areas to adopt and enforce a floodplain management ordinance. Implementation regulations are at 12 Pa. Code Chapter 113. Within Lehigh County, the Lehigh River, Jordan Creek, Little Lehigh Creek, Cedar Creek, and Trout Creek all generate FEMA-mapped Special Flood Hazard Areas (Zones A, AE, and floodway) on Flood Insurance Rate Maps (FIRMs). Each Lehigh County municipality enforces its own FEMA-approved floodplain ordinance that must meet the minimum requirements of 44 CFR §60.3 (federal NFIP standards) and 12 Pa. Code Chapter 113. Pennsylvania requires more stringent freeboard than the federal minimum: under 12 Pa. Code §113.3 and Act 166, the lowest floor (including basement) of a new or substantially improved residential structure in the SFHA must be elevated at least 1.5 feet above the base flood elevation - this exceeds the federal 0-foot freeboard minimum. Non-residential structures may be elevated or dry-floodproofed to the same 1.5-foot freeboard. The 'substantial improvement' rule applies when the cost of repair, reconstruction, or alteration over a 10-year period equals or exceeds 50% of the structure's pre-improvement market value (12 Pa. Code §113.3), triggering full code compliance. Floodway development that increases base flood elevations is prohibited. A floodplain development permit must be issued by the local floodplain administrator before any construction, fill, grading, or substantial improvement in the SFHA. FEMA Flood Map Service Center (msc.fema.gov) hosts the official FIRMs. Lehigh County's planning office and the Pennsylvania Emergency Management Agency (PEMA) provide technical assistance.