Potomac Interceptor LZ07 Project

Potomac Interceptor LZ07 Project


This project primarily involves rehabilitation of the Potomac Interceptor (PI) pipe segments around MH31. The PI is a critical component of DC Water’s sewer system serving Loudoun and Fairfax counties in Virginia and Montgomery County in Maryland. The PI conveys sewage from these areas to the Potomac Pumping Station in DC. From the Pumping Station, the flow is then sent to the Blue Plains Advanced Wastewater Treatment Plant for treatment. DC Water has been conducting assessments of the PI and has several Capital Improvement Projects to rehabilitate defective segments. 

Scope of Work

  • Rehabilitation of 140 feet of 54-inch diameter Reinforced Concrete Pipe (RCP) immediately downstream from Manhole 31
  • Replacement of Manhole 31
  • Replacement of 200 feet of 54-inch diameter RCP immediately upstream of Manhole 31
  • Installation of temporary bypass pumping during construction
  • Installation of an energy dissipation structure



  • Design Start: May 2020
  • Construction start: Q2 2022 
  • Construction completion: End 2023
  • Normal Work Hours: 7:30 pm to 5:30 am, Monday through Friday; dependent upon permit approval, contractors may work during the day or on weekends due to certain rehabilitation activities, or inclement weather delays.


Important Information

  • DC Water will work to ensure disruptions are minimized to the extent possible during construction operations and will restore all work sites to their original condition.
  • Sewage odor may be noticed temporarily during the construction operation.
  • To ensure the continued safety of trail users during construction, DC Water will:
  • Temporarily relocate the Potomac Heritage Trail.
  • Install a temporary footpath for community members to access the trail.
  • Install a temporary perimeter fence around the construction site area.


Traffic Plan

  • Flaggers & escorts will be used (on authorized roads) for deliveries of materials to the project site.
  • Gravel pull-offs will be installed to maintain safe passage for construction and private vehicles.
  • Speed bumps & signage will be installed to maintain a safe speed for construction vehicles.
  • The existing columns on Yarnick Road will be temporarily relocated to allow for safe passage of construction vehicles, and to ensure their safety during construction; the columns will be restored upon completion of the work.



DC Water will coordinate with NOVA Parks, local government agencies, area residents, and other community stakeholders to minimize disruption during this project.


Contact Information

DC Water Community Outreach Manager: Emanuel Briggs (202) 787-2003, emanuel.briggs@dcwater.com

DC Water Project Manager: Pubudu Ranasinghe (202) 787-2310, pranasinghe@dcwater.com

LZ07 Project Owner’s Adviser: Robert Dudley (202) 787-7714, bob.dudley@ramboll.com

DC Water 24-hr Emergency/Command Center: (202) 612-3400

Upcoming Meeting

Board of Directors Meeting

April 24, 2023

Monday 9:00 AM

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