# County of Adams

**URL:** https://aqualisco.com/compliance_item/county-of-adams/
**Author:** Carlie Utesch
**Published:** August 15, 2019

> Last Updated 08/07/2026 The County of Adams regulations are compliant with the National Pollutant Discharge Elimination System (NPDES) through municipal regulation Stormwater Management Ordinance. The county’s Municipal Separate Storm Sewer System (MS4) requires Adams to administer and enforce compliance with...

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Last Updated 08/07/2026

								
				
				
				
									The County of Adams regulations are compliant with the National Pollutant Discharge Elimination System (NPDES) through municipal regulation Stormwater Management Ordinance. The county’s Municipal Separate Storm Sewer System (MS4) requires Adams to administer and enforce compliance with stormwater discharge permits in an effort to decrease stormwater pollutants and increase overall water quality. All Act 167 designated watersheds and municipalities in Adams County are required to follow Adams County stormwater regulation.

								
				
				
				
					
## EXCERPT- Adams Ordinance Chapter 23 Stormwater Management
				
				
				
		
				
				
					
### ARTICLE III – STORMWATER MANAGEMENT STANDARDS
				
				
		
				
				
					
#### Section 301. General SWM Site Plan
				
				
				
				
									Requirements

A. For all regulated activities, unless preparation of an SWM Site Plan is specifically exempted in Section 302:

1. Preparation and implementation of an approved SWM Site Plan is required.

2. No regulated activities shall commence until the Municipality issues written approval of an SWM Site Plan which demonstrates compliance with the requirements of this Ordinance.

								
				
				
				
				
									
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									Need Help Interpreting Requirements?
					
					](https://aqualisco.com/request-a-consultation/)
				
								
				
		
				
				
					
#### Section 305. Rate Controls
				
				
				
				
									A. Post-development discharge rates shall not exceed the pre-development discharge rates for the 1-, 2-, 5-, 10-, 25-, 50-, and 100-year 24-hour storms. If it is shown that the peak rates of discharge indicated by the post-development analysis are less than or equal to the peak rates of discharge indicated by the pre-development analysis for 1-, 2-, 5-, 10-, 25-, 50-, and 100-year, 24-hour storms, then the requirements of this section have been met. Otherwise, the applicant shall provide additional controls as necessary to satisfy the peak rate of discharge requirement.

B. For computation of pre-development peak discharge rates, twenty percent (20%) of existing impervious areas, when present, shall be considered meadow.

								
				
				
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									View State Page

								
				
				](https://aqualisco.com/compliance_item/pennsylvania/)
				
				
					
				
		
					
		
				
				
					
### Resources
				
				
				
				
							
			
						
		
						
				
				
		
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### Adams, PA Stormwater Code
				
				
		
				
				
									View Ordinances

								
				
				
				
							
			
						
		
						
				
				
				](https://ecode360.com/14998798#14998798)
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### Pennsylvania Stormwater SOP
				
				
		
				
				
									View PDF

								
				
				
				
							
			
						
		
						
				
				
				](https://www.pa.gov/agencies/dep/programs-and-services/water/clean-water/stormwater-management)
				
					
				
		
					
				
				
					
## Frequently Asked Questions
				
				
				
				
							
						
				
					 Does my completed development need to meet a specific runoff rate standard in Adams County? 
							
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									Yes, on an ongoing basis. Once developed, your site’s peak discharge rate cannot exceed its pre-development discharge rate for the 1-, 2-, 5-, 10-, 25-, 50-, and 100-year 24-hour storm events. This is a performance standard your finished site needs to continue meeting, not just a one-time design target. AQUALIS can help property owners confirm their completed site is still performing to this standard over time.

								
				
				
					
						
				
					 How is my property's pre-development discharge rate calculated in Adams County, Pennsylvania? 
							
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									For this calculation, 20% of any existing impervious area on the site is treated as meadow. This affects the baseline your completed development’s runoff is measured against.

								
				
				
					
						
				
					 Who administers stormwater compliance in Adams County? 
							
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									Adams County administers and enforces stormwater discharge permit compliance under its Municipal Separate Storm Sewer System (MS4) permit, working to reduce pollutants and improve water quality. All Act 167 designated watersheds and municipalities within the county are required to follow the county’s stormwater regulations.

								
				
				
					
					
						
				
					
				
		
					
				
				
									The information on this page is provided for general informational purposes only and is not legal advice. Regulations change frequently — AQUALIS makes no warranty as to the accuracy or completeness of this content, and any reliance on it is at your own risk. Consult a qualified professional or your local regulatory authority to confirm requirements applicable to your specific property.