Wet weather events (e.g., rain, snowmelt) can affect operations at publicly owned treatment works (POTWs) when excess water enters the wastewater collection system. Large wet weather events can exceed the POTW's capacity to provide the same type of treatment for all of the incoming wastewater. This update to the regulations will seek to clarify permitting procedures under 40 CFR part 122 to provide POTWs with separate sanitary sewer systems flexibility in how they manage and treat peak flows under wet weather conditions. These updates will also seek to ensure a consistent national approach for permitting POTWs that allows efficient treatment plant operation while protecting the public from potential adverse health effects of inadequately treated wastewater.