Environmental Rules in Delaware County, PA (2026)
4 rules for unincorporated Delaware County, Pennsylvania.
Verified from official government sources
Stormwater Management
Delaware County's stormwater chapter is the 1989 Ridley Creek ordinance: it applies only inside the Ridley Creek watershed, only where a municipality has no subdivision ordinance of its own, and exempts projects under 7,500 square feet of new impervious surface.
Ridley Creek Watershed Stormwater Rules in Delco
Some RestrictionsDelaware County, PA Code § 187-4
This chapter shall apply to all forms of land alteration and disturbances relating to subdivisions and land developments within the Ridley Creek watershed, unless specifically exempted or modified by this chapter, being undertaken in those cities, boroughs, or townships of the First or Second Class wholly or partly within the County of Delaware, and which have no subdivision ordinance in effect...
Erosion Control
Delaware County's subdivision ordinance does not set its own numeric erosion and sediment control standards; it sends every project to the municipality's stormwater ordinance and to Chapter 102 of the Pennsylvania Code. The county's older floodplain ordinance adds one hard trigger: developments of 25 acres or more need a state DEP soil and erosion permit before construction starts.
Delaware County PA Erosion Control Rule
Some RestrictionsDelaware County Code § 195-814; § 62-7C
§ 195-814. Soil erosion and sedimentation control. All soil erosion and sedimentation control practices shall be in accordance with the applicable sections of the municipality's stormwater management ordinance and compliant with Chapter 102 of the Pennsylvania Code. ... § 62-7C. Prospective developers should consult the Delaware County Conservation District representative concerning erosion and...
Flood Zones
Delaware County's Floodplain Protection Ordinance, Chapter 62, blocks subdivision or land-development approval that would raise the one-hundred-year flood elevation more than one foot and bars new residential building sites inside any floodway. It steps in only where a Delco municipality has no floodplain-compliant subdivision ordinance of its own, filed with the County Planning Department.
Delaware County PA Floodplain Development Rules
Some RestrictionsDelaware County Code § 62-10B
No subdivision and/or land development, or part thereof, shall be approved if the proposed development and/or improvements will, individually or collectively, increase the one-hundred-year flood elevation more than one foot at any point. C. Building sites for residences or any other type of dwelling or accommodation shall not be permitted in any floodway area. Sites for these uses may be per...
Flood Elevation Requirements
Delaware County's floodplain code sets the "regulatory flood elevation" at the one-hundred-year flood elevation plus a 1.5-foot freeboard safety margin. Chapter 62 requires building sites, sewer systems, water systems and other utilities in a designated floodplain district to be elevated or floodproofed up to that regulatory elevation before the county will approve a subdivision plan.
Delaware County Freeboard Elevation Standard
Some RestrictionsDelaware County Code § 62-12
REGULATORY FLOOD ELEVATION The one-hundred-year flood elevation plus a freeboard safety factor of 1 1/2 feet. STRUCTURE Anything constructed or erected on the ground or attached to the ground, including, but not limited to, buildings, factories, sheds, cabins, mobile homes, and other similar items. SUBDIVISION The division or redivision of a lot, tract or parcel of land by any means into t...
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