EPA Publishes Final Rule Clarifying Phase II Stormwater Regulations Related to Census Bureau Urban Area Designations
On June 7, 2023, the EPA Administrator signed its final rule, NPDES Small MS4 Urbanized Area Clarification, to clarify the designation criteria for small MS4s following the Census Bureau’s recent urban area mapping revisions. EPA provided notice of the final rule’s promulgation in the Federal Register on June 12, 2023. The effective date for the final rule is July 12, 2023.
The final rule clarifications are necessary due to the Census Bureau’s March 24, 2022 publication of final program criteria (pdf) (286.6 KB) that discontinued its practice of publishing the location of “urbanized areas” along with the 2020 Census and future censuses. The clarifications in this final rule replace the term “urbanized area” in the Phase II regulations with the phrase “urban areas with a population of at least 50,000,” which is the Census Bureau’s longstanding definition of the term urbanized areas. This change allows NPDES permitting authorities to use 2020 Census and future Census data in a manner that is consistent with existing longstanding regulatory practice.
For any questions related to this announcement, please contactHuddle.Heather@epa.gov. Do not respond directly to this e-mail, as this inbox is not monitored.