Allentown, PA Environmental Rules: Stormwater Management (2026)

Chapter 538 (Ord. No. 14476, adopted 4-19-2007) governs the Jordan Creek, Little Lehigh Creek, Monocacy Creek, and Lehigh River Subbasins watersheds within the City. Regulated activities include land development, subdivision, construction of new or additional impervious surfaces such as driveways and parking lots, new buildings or additions, diversion or piping of a stream channel, installation of stormwater systems, and regulated earth disturbance activities. Under Sec. 538-6, any regulated activity that creates 10,000 square feet or less of additional impervious cover is exempt from the drainage plan preparation requirement, but impervious cover added incrementally above that 10,000-square-foot threshold must comply, and no exemption applies to stream diversions or stormwater system installations.

Drainage plans for subdivisions and land developments go to the City's Planning Bureau and Bureau of Engineering (two copies); building-related activity plans go to the City's building permit officer; projects over 10,000 square feet of added impervious cover also route to the Lehigh Valley Planning Commission for an advisory consistency review. The City Engineer reviews each plan against the adopted watershed stormwater management plan and any DEP permits, and the City cannot approve a subdivision, land development, or building permit if the drainage plan is inconsistent with that plan.

Applicants facing unnecessary hardship may request a written waiver with a fee, but the City cannot waive the chapter's water-quality provisions, and financial hardship alone is not a valid basis for relief. The City Engineer or a designee may inspect construction, operations, and maintenance of stormwater best management practices at any stage and may suspend or revoke a permit if BMPs are not implemented as required.