Water quality: Municipal MS4 urban area maps

Status of 2020 Urban Areas

On March 24, 2022, the US Census Bureau finalized Urban Area Criteria for the 2020 Census. Census Urbanized Areas are the primary factor EPA and states use to determine regulated Small MS4 areas. The division is following the developments and is awaiting information from EPA on how the new criteria will impact MS4 permitting. At this time, 2020 urban area maps have not been released; however, this page will be updated when they become available.

2010 Urban area map fact sheet


2010 urban area maps


2000 urban area maps