From: Ann Morbitt Sent: Tuesday, May 31, 2022 2:16 PM To: April Grippo; Ariel Wessel-Fuss; Brown Patton Subject: FW: MS4 Waivers & Status of U.S. Census Bureau's 2020 Urban Area Reference Maps FYI From: Kuo, Mary Sent: Tuesday, May 31, 2022 2:01 PM To: Ann Morbitt Subject: [EXTERNAL] RE: MS4 Waivers & Status of U.S. Census Bureau's 2020 Urban Area Reference Maps *** This is an EXTERNAL email. Please exercise caution. DO NOT open attachments or click links from unknown senders or unexpected email - STS-Security. *** Hi Ann, Language from the Phase II Preamble [64 FR 68751]: “Additional designations based on subsequent census years will be governed by the Bureau of the Census’ definition of an urbanized area in effect for that year. Based on historical trends, EPA expects that any area determined by the Bureau of the Census to be included within an urbanized area as of the 1990 Census will not later be excluded from the urbanized area as of the 2000 Census. However, it is important to note that even if this situation were to occur, for example, due to a possible change in the Bureau of the Census’ urbanized area definition, a small MS4 that is automatically designated into the NPDES program for storm water under an urbanized area calculation for any given Census year will remain regulated regardless of the results of subsequent urbanized area calculations.” I hope this helps, Mary From: Ann Morbitt Sent: Tuesday, May 31, 2022 12:55 PM To: Kuo, Mary Subject: MS4 Waivers & Status of U.S. Census Bureau's 2020 Urban Area Reference Maps Hello Mary, I hope you are doing well. I was asked to reach out to you to see if there were any examples EPA could provide related to states granting waivers to MS4s that have already received coverage under an MS4 permit. Also, whether EPA has any updates regarding the status of the 2020 U.S. Bureau’s Urban Area Reference Maps. If it would be more convenient to discuss please let me know when you are available and we can schedule a time to discuss. Thanks, Ann Ann Morbitt I Integrated Water Resources Consultant Tennessee Department of Environment & Conservation Division of Water Resources 711 R.S. Gass Blvd., Nashville, TN 37216 (615) 687-7119