EPA Releases Phase II Rule Clarification Related to Urban Area Designation Criteria

EPA is clarifying its NPDES Stormwater Phase II regulations due to the Census Bureau’s recent change that discontinued the practice of defining and publishing the location of “urbanized area.”  EPA has relied on this designation for some small municipal separate storm sewer systems (MS4s) since the promulgation of the Phase II regulations in 1999.  EPA is replacing references in the Phase II regulations to “urbanized area” with “urban areas with a population of at least 50,000,” which is the Census Bureau’s longstanding definition of the term urbanized areas.  Because the text changes maintain the current scope of which entities are regulated as small MS4s, EPA published them in the Federal Register as a direct final rule.  The direct final rule will become effective on March 2, 2023, without further notice, unless EPA receives adverse comment by January 3, 2023. 

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To access the Federal Register notice, please click here.