Public Works and Environmental Services

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Carey Needham
Director, Capital Facilities

Accotink Gravity Sewer Improvements Project

Project Number: WW-000032-027

Project Update: May 15, 2024

Design progress continues. Comments have been received, addressed, and resubmitted for VADEQ and ACOE project permits. VDOT project permit comments are currently being reviewed and responses are being prepared. Coordination with directly affected owners is currently in progress. Design and construction coordination discussions with WMATA continue.

Project Background

The Fairfax County Department of Public Works and Environmental Services, which is responsible for wastewater collection and treatment in Fairfax County, is working on several wastewater infrastructure projects to collect and treat the additional wastewater that is anticipated to come from the northern parts of Fairfax County. The Accotink Gravity Sewer Improvements project is one of these projects. The goal of the project is to increase the capacity of the sewer system to accommodate the anticipated growth in the northern Fairfax County area and to ensure the system continues to provide continuous reliable service to all customers. Since it can take a considerable amount of time to effectively plan, design, construct, and bring these types of facilities online, the county is working on improvements now to stay ahead of these capacity needs.

Project Description

The county has been studying future flow projections for the northern Fairfax County area and has compared these projections to current available capacity. The studies show that facilities in the northern Fairfax County area have insufficient capacity to handle future flows. The studies concluded there is capacity to treat these flows at the county operated Noman Cole Pollution Control Plant, in Lorton VA. Capacity improvements in the sewer collection system are needed to modify and expand the capacity of the existing sewerage system to allow the flows to be transported to this plant for treatment.

Planning activities for this project have been completed and the selected plan will involve the construction of approximately 15,000 feet on new sewer pipe which will be integrated with the existing sewerage system to provide the capacity needed.

Project Location

map - Accotink Gravity Sewer

Project Phase

The project is in planning phase.


Planning Summer 2021 - Summer 2022
Design Summer 2022 - Spring 2023
Construction Completes Spring 2025

What to Expect

Area residents, business owners, and other key stakeholders located near the selected pipeline route will have an opportunity to hear a presentation on our planning process and provide input on the selected route. The county will publish information from this presentation on the project website. The project will be transitioning into design related activities soon. During design, more specific information will be developed for the project and the county will continue with a public outreach program and will begin to target specific stakeholders who may be directly impacted by the project. Once the design has been finalized and the project begins to transition into construction, the public outreach program will continue to provide construction related information.

Project Cost and Funding Source

The estimated cost for this project is approximately $37 million. The project is being funded through Sewer Use fees and Availability Charges which are assessed when new connections are made to the system.

Presentations to the Community

A virtual public meeting to review the project and answer questions from the community was held May 24, 2022.


For more information, please email the project manager, Thomas Grala at

Frequently Asked Questions

A portion of the alternatives are in an area under the jurisdiction of Vienna. Fairfax County has existing pipes located in these areas and we will be modifying these facilities in all the alternatives evaluated. Preliminary discussions have been held with Vienna and agreement has been reached to continue discussions of these modifications.

Fairfax is required to operate the sewer system in accordance with federal permit requirements. This permit requires that the sewer system be constantly maintained and monitored for compliance. This includes evaluating the system for any improvements needed to properly operate the existing system and evaluate needs for expansion and growth. The Tysons program projects were conceived as a result of these evaluations. Individual projects in the program were developed in the context of the overall system goals and project specific needs and have been coordinated in the context of their fit and implementation into the overall sewerage system.

During development of alternatives for each individual project, the recommendations for each were also evaluated in terms of the improvements to the overall sewerage system. In the context of this overall coordination, it was determined that the alternate 7 higher head, longer force main did not provide any overall significant benefit over the selected alternative force main with lower head, shorter force main, and an incremental gravity pipe increase in the area north of the force main connection where improvements to the pipe capacity will be required.

Alterative concepts are developed to address the needs of the project. These alternatives are screened to determine if they are feasible to properly address the needs of the project. Once alternatives were screened to a smaller number of viable alternatives, this subset of alternatives were evaluated and ranked in detail to determine the selected alternative.

While the existing sewer system is sized to handle future flows from these areas, it is adversely impacted by new flows coming from the Tysons West pump Station. These combined flows result in capacity improvements being necessary to the current gravity sewer.

Current Fairfax County practice is to complete what is known as a Value Engineering (VE) study for projects of this magnitude. These VE studies are done by an independent team of wastewater professionals who are completely independent of any county staff, or design consultants currently involved with the projects. This VE process results in an independent review of the project concepts and results in a series of recommendations for ways to approach the project differently to achieve cost savings.

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