Plans are underway to design a project that will upgrade part of a massive sewer line serving portions of Northern Virginia and Maryland.

About 600 feet of D.C. Water’s Potomac Interceptor will be rehabilitated along the historic Potomac Heritage Trail.

It carries sewage from Fairfax and Loudoun counties in Virginia and from Montgomery County in Maryland — on a path ultimately ending at the Blue Plains wastewater treatment plant in Southwest D.C.

The line is 65 feet underground and ranges in size from 54 inches (4.5 feet) to 78 inches (6.5 feet).

Upgrading the 60-year-old line will involve either a permanent or temporary diversion of the pipe to ensure continuity of service.

The part of the plan currently underway is setting up a stakeholder outreach program to get the community involved in helping shape the project’s path forward.

The project design should be set by 2021. Then, when work begins, “construction will be methodically scheduled to reduce impact on neighboring communities and a popular regional park,” according to a statement from Ulliman Schutte/Brown and Caldwell. D.C. Water hired them to provide design, engineering and construction services for the project.