Backflow preventers are required on water services to every property in order to protect the public water system and the occupants of every building.

DCWASA regulates the requirements for backflow preventers on water services throughout the District of Columbia. Chapter 54 of the District of Columbia Municipal Regulation (DCMR) 21 contains the regulations for backflow prevention. All of the requirements and conditions of this law can be found in the DCWASA cross connection manual, which can be purchased at the DC WASA Document and Permits Office at 5000 Overlook Avenue, S.W. 20032.

DCWASA approves the size, type, and location of backflow preventers for new buildings and buildings that are being renovated. Backflow preventers are required for domestic and fire protection water pipes to commercial, industrial, educational and residential buildings including single family homes. DCWASA approved select backflow preventers for use in the District of Columbia (Click here to see this list). The project designer must select the correct type and size backflow preventer.

DCWASA reviews construction plans during the building permit or plumbing permit process. The DCWASA checklist, which is located in the general information of the Permits section, contains the name, telephone numbers, and office location of the DCWASA staff who review backflow preventer designs.

Ms. Priscilla Hodnett will review the design of backflow preventers on domestic or fire protection services that are 2" in diameter and smaller. Her telephone number is (202) 787-2496. Domestic backflow preventers shall meet the requirements of ASSE# 1013 or 1015. A completed backflow prevention form is required to be submitted with the plans before the backflow preventer design can be approved (Click here for Backflow Prevention form).

Mr. E. Chiang Lee will review and approve the design of backflow preventers on 3" and larger water services. You can reach Mr. Lee at (202) 787-2395, and his office is at 5000 Overlook Avenue, SW, Washington, DC 20032. Separate backflow preventers are required for domestic and fire protection services even if the property has a single water service. The fire protection water services shall have detector check water meters, which meet either ASSE# 1047 or 1048. These water meters will meet the requirements of backflow preventers. Domestic backflow preventers shall meet the requirements of ASSE# 1013 or 1015. Applicants must submit the plumbing plans for the proposed project and the civil plan for the water pipes within public space. The backflow prevention form is also required to be submitted with the plans before the backflow preventer design can be approved.

D.C. law requires owners to have every backflow tested once per year by a certified backflow preventer. The results of this test must be submitted to the DCWASA water quality staff at Fort Reno site.