Lehigh County, PA Environmental Rules: Stormwater Management (2026)
Key Facts
- Governing chapter
- SALDO Ord. 2025-167, §§ 460-462
- Applies in
- municipalities without own SALDO
- Plan reviewer
- Lehigh Valley Planning Commission
- Standard
- Act 167 release-rate criteria, Appendix B
- Return periods controlled
- 2-, 10-, 25-, 100-year peak runoff
- Easement freeboard
- 0.5 foot above design water level
Summary
Lehigh County's Subdivision and Land Development Ordinance requires a site drainage plan for every covered subdivision, with runoff controlled to Act 167 release-rate criteria in Appendix B and reviewed by the Lehigh Valley Planning Commission engineer. It applies only in the small number of county municipalities that never adopted their own subdivision ordinance.
461.5 ... No stormwater runoff or natural drainage shall be so diverted as to overload existing drainage systems, or create flooding or the need for additional drainage structures on other private properties or public lands, without approved provisions being made by the developer for properly handling such conditions. ... 462.1 A site drainage plan for the proposed subdivision tract shall be prepared which illustrates the complete drainage systems for the subdivision. ... 462.2 The site drainage plan for the proposed subdivision shall meet the requirements of the Act 167 Storm Water Management Ordinance as included in Appendix B.
Full Breakdown
Under Section 101 of the Lehigh County Subdivision and Land Development Ordinance (Ord. 1 limits its jurisdiction to plans in those same non-adopting municipalities. Most Lehigh Valley municipalities, including Allentown, have their own subdivision ordinances, so this county chapter does not reach them. 5 bars diverting runoff so it overloads existing systems or floods other private or public land without developer-provided handling measures. 2 ties that plan to the Act 167 Storm Water Management Ordinance release-rate and calculation methodology set out in Appendix B, Sections 101 through 103, which sorts each site into a Conditional No Detention, Dual Release Rate, or Single Release Rate district and sets 2-, 10-, 25- and 100-year peak runoff controls of 30% to 100% of predevelopment rates.
9 requires drainage easements sized for the 100-year return period plus a half-foot freeboard allowance where a site is crossed by a watercourse without a municipally defined floodplain.
Violations & Fines
The LVPC Engineer reviews every site drainage plan submitted with a subdivision or land development application under this ordinance, and final plan approval does not issue until the drainage design, easements and any required PennDOT approval are in place. A development that diverts runoff so it overloads downstream drainage systems or floods adjoining property without approved handling provisions violates Section 461.5 and can hold up plan approval or improvement agreement sign-off until the design is corrected.
Frequently Asked Questions
Does Lehigh County's stormwater ordinance apply to my subdivision?
What does a developer have to submit for drainage?
Can a developer just divert runoff onto a neighboring property?
Sources & Official References
Other rules in Lehigh County
Compare Lehigh County to another location·View the Pennsylvania environmental rules overview
See something wrong?
Help us keep this page accurate. If you notice an error or outdated information, let us know.