Countywide Model Stormwater Ordinance

The Delaware County Planning Department, with Cedarville Engineering Inc., updated the Countywide Model Stormwater Management Ordinance.

The updated Model Ordinance is designed to comply with the regulatory requirements of Pennsylvania Department of Environmental Protections’ (PA DEP) National Pollutant Discharge Elimination System (NPDES) Municipal Separate Storm Sewer System (MS4) program. The updates incorporated into the Model Ordinance are also designed to comply with the provisions included in PA DEP's 2022 Model Stormwater Ordinance.

The updated Model Ordinance is intended to be applicable countywide, and it is Delaware County’s first step in determining the feasibility of countywide updates for Act 167 plans. Below are links to the word documents of the updated Model Ordinance and Appendices B and I, which have changes. Appendices A,C,D,E,F,G,H and J had no changes in this update to the Generic Crum Creek Ordinance.

As a reminder, the stormwater ordinance updates must be adopted by September 30, 2022 and submitted to PA DEP with the Annual MS4 Status Report. As you are working to complete the updates, please refer to the below information for clarification on impervious surface and earth disturbance thresholds required in the updated stormwater ordinance.

Impervious Surface and Earth Disturbance Threshold Clarification:
The Delaware County-wide Model Stormwater Management Ordinance utilized the Crum Creek Generic Model Ordinance as a base, then updated it for compliance with the 2022 PA DEP MS4 requirements. The minimum impervious surface and earth disturbance thresholds regulated in the Delaware County-wide Model Ordinance are required for those municipalities located within the Crum Creek watershed. If your municipality is not located within the Crum Creek watershed, you may comply with the minimum impervious surface and earth disturbance provisions in the applicable Act 167 Plan model ordinance watershed(s) in which you are located.

If your municipality does not fall within the boundaries of a watershed(s) with thresholds assigned in the applicable model ordinance, the County recommends adopting those in the Delaware County-wide Model Ordinance if possible. At a minimum, municipalities must update their ordinance for compliance with the 2022 PA DEP MS4 requirements and adopt by September 30, 2022. The PA DEP MS4 requirements should not require any changes to impervious surface or earth disturbance thresholds.

Note that your ordinance is not required to be compliant with the Delaware County-wide Stormwater Management Model Ordinance, only with the applicable Act 167 model ordinance and 2022 PA DEP MS4 requirements. The Delaware County-wide Stormwater Management Model Ordinance is provided as a tool for municipalities to use in accomplishing this.

In addition, municipalities may elect to make their ordinances more stringent than the model ordinances should they choose.

		Ridley Creek Act 167 (1988)*	Chester Creek Act 167 (2002)	Darby-Cobbs Creek Act 167 (2005)	Crum Creek Act 167 (2011)	Brandywine Creek Act 167 (Chester County-wide, 2022)
IMPERVIOUS SURFACE THRESHOLDS	Exempt	n/a	0-999 ft2	0-2,000 ft2	0-499 ft2	0-999 ft2
	Modified/Simplified Approach Required	n/a	1,000-2,000 ft2 or 10% of total lot size, whichever is less	n/a	500-999 ft2	n/a
	Modified/Simplified Approach Optional	n/a	n/a	n/a	n/a	1,000-1,999 ft2
	Full Ordinance Applies	n/a	>2,000 ft2	>2,000 ft2	≥1,000 ft2	≥2,000 ft2
EARTH DISTURBANCE THRESHOLDS	Exempt	n/a	n/a	0-5,000 ft2	0-4,999 ft2	0-4,999 ft2
	Exempt from Rate Controls	n/a	n/a	n/a	5,000 ft2 to 0.99 acre	5000-9,999 ft2
	Full Ordinance Applies	n/a	n/a	>5,000 ft2	≥1 acre	≥10,000 ft2

*There is no model ordinance associated with the Ridley Creek Act 167 Plan.

Summary of Changes Table

Countywide Model Stormwater Management Ordinance

Appendix B – Simplified Approach

Appendix B - Simplified Approach Tables

Appendix I – O&M Agreement

Appendices A,C,D,E,F,G,H, and J

Take the Survey! In this quick, 5-question survey, you will be able to give us input on Stormwater Management Planning.

Presentation from the Stakeholder Meeting on April 19, 2022

Presentation from the Municipal Workshop Meeting on May 26, 2022

Questions about the Countywide Model Stormwater Ordinance? Contact the Planning Department at 610-891-5200 or stauffera@co.delaware.pa.us.