CSO 025 / 026 Sewer Separation Project


The Combined Sewer Overflow (CSO) 025/026 Sewer Separation project is part of the DC Water Clean Rivers Project’s goal to reduce the volume of combined sewer overflows to the Potomac River to improve water quality and meet Consent Decree requirements. In addition to constructing a tunnel and green infrastructure, DC Water is using sewer separation for two CSO outfalls—CSOs 025 and 026.

The concept of sewer separation means routing sanitary flow to new sewers that will exclusively carry sanitary flow and convey stormwater runoff through the existing piping system that formerly carried combined storm and sanitary flow. The CSO 025/026 sewer system is located within Georgetown, south of the C&O Canal, and collects flow from the blocks bounded by Cecil PL NW, Wisconsin Ave NW, 31st ST NW, and Thomas Jefferson ST NW.

The map below shows the project areas. Construction will occur at three project sites:
•    Water Street NW Project Site
•    Wisconsin Avenue NW Project Site
•    31st Street NW Project Site


Activity Date
Data Collection/Investigation Complete
Design Complete
Construction Begins 4/2021
Construction Complete 9/2022

Community Meeting

Join us on April 20th to learn more about this project. Zoom meeting details below.

When: Apr 20, 2021 06:30 PM Eastern Time (US and Canada)

Click the link join the webinar: https://us02web.zoom.us/j/81741942834

Or Dial: +1 301 715 8592  
Webinar ID: 817 4194 2834