RiverRenew Sewage Remediation Project Hits Major Milestone: Report

ALEXANDRIA, VA – Alexandria has begun testing a huge tunnel system designed to keep sewage out of the Potomac River, the Zebra reports.

AlexRenew, Alexandra’s wastewater servicer, has been working for years on a project to remediate the city’s combined sewer outfalls. In 2024, AlexRenew completed the 2.2-mile Waterfront Tunnel. Now, that tunnel system is being put through its paces.

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The Zebra reports that AlexRenew began accepting test flows of water into the tunnel system the week of April 20th. These test flows will be used to assess equipment ahead of the project’s operational deadline, originally set for July 2025 but pushed back to July 2026.

The massive RiverRenew project is the city’s attempt to remediate Alexandria's old, combined sewer outfalls and prevent pollution into waterways, as required by the Virginia General Assembly. The combined sewer outfalls, serving about 6 percent of Alexandria, date back to the 1860s and risk sending sewage to the Potomac River, Hooffs Run and Hunting Creek if the pipes are overwhelmed by heavy rain.

New infrastructure from the RiverRenew project will instead capture the wastewater and send it to treatment before the water enters the Potomac River. The project is the largest infrastructure project in Alexandria’s history, according to RiverRenew, and involves not only the Waterfront Tunnel and new pipelines, but underground diversion facilities to capture sewage and new pumping stations to move it.

In 2025, the city approved a 10 percent rate increase over two years to help pay for the mammoth project.

The Potomac experienced a catastrophic spill in January when a 6-foot interceptor pipe operated by DC Water collapsed in Montgomery County, Maryland, releasing an estimated 243 million gallons of untreated sewage directly into the Potomac River, according to the Potomac Riverkeeper Network, possibly the worst sewage spill in U.S. history.

Read more from the Zebra here.