12-F DCMR 603
603. WATER SERVICE
Cite as D.C. Mun. Regs. tit. 12-F, ยง 603
603 WATER SERVICE
Strike Section 603.1 of the International Plumbing Code in its entirety and insert a new Section 603.1 into the Plumbing Code in its place to read as follows:
603.1 Size of water service pipe. The water service pipe shall be sized to supply water to the structure in the quantities and at the pressures required in this code. New water service pipe shall be not less than 1 inch (25.4 mm) in nominal size diameter.
Insert new Sections 603.3, 603.3.1, 603.3.2 and 603.3.3 into the Plumbing Code to read as follows:
603.3 Water service piping protection. Water service piping shall be protected against backflow in accordance with Sections 603.3.1 through 603.3.3.
603.3.1 Water service piping backflow prevention. A backflow preventer shall be installed on the water service pipe, downstream of the water meter, in compliance with Table 603.3.1, for every new water service, and for existing water services as required by Section 603.3.3. Backflow preventers shall be installed in accordance with manufacturer's installation instructions and DC Water design specifications, and shall be located upstream from any served water outlet.
603.3.2 High risk non-residential structure. Any building, structure or campus that is or contains a facility hereafter classified as a high risk non-residential structure shall be required to install a reduced pressure principle backflow prevention assembly conforming to ASSE 1013 on the water service connection. High risk non-residential facilities include, but are not limited to, hospitals, hemoglobin dialysis centers, funeral homes or mortuary facilities, chemical manufacturing plants, car wash facilities, sewage treatment plants, auxiliary water supply systems, wells, dry cleaning plants, breweries, distilleries, laboratories, facilities where radioactive materials are handled, and facilities with a water reuse system.
603.3.3 Existing water service piping. Installation of a backflow preventer in an existing water service pipe shall be required only in the following cases:
1. Construction of a new structure reusing the existing service.
2. Alteration of the existing water distribution system of the structure affecting fixtures that in aggregate account for more than 75 percent of the demand load of the existing installed system, calculated in accordance with Section 604.3, not including minor piping adjustments for fixture replacements.
3. Addition to the existing water distribution system of the structure that will result in an increase of more than 50 percent in the demand load of the existing installed system, calculated in accordance with Section 604.3.
4. The served existing structure has been or is heretofore classified as a high risk non-residential structure.
5. When the existing water service pipe is replaced.
6. When the meter setter is replaced.
Insert new Table 603.3.1 in the Plumbing Code to read as follows:
TABLE 603.3.1 WATER SERVICE BACKFLOW PREVENTION
Water Service Backflow Preventers
Facility type Service Size Type Location
Note a Residential or nonresidential 5/8โ, 3/4:โ 1", 1 1/2" and 2" ASSE 1024 Dual
Check Valve On the discharge side
of meter yoke
Note b Non-residential 3" and larger ASSE 1015 Double
Check Backflow Prevention Assembly Inside facility, within
10 feet of water
service point of entry prior to any pipe branching High Risk Nonresidential Any ASSE 1013 Reduced
Pressure Principle Backflow Prevention Assembly
Fire Protection Backflow Preventers
Water Treatment Type Location
Note a No chemical additives ASSE 1015 Double Check
Fire Protection Backflow Prevention Assembly
ASSE 1048 Double Check
Detector Fire Protection Backflow Prevention
Assembly Inside facility, within 10 feet
of water service point of entry Treated with chemical
Additives ASSE 1013 Reduced
Pressure Principle Backflow Prevention Assembly
ASSE 1047 Reduced pressure detector fire protection backflow prevention assembly
For SI: 1 inch = 25.4 mm, 1 ft = 304.8 mm, 1 pound per square inch = 6.895 kPa.
a - Backflow preventers shall always be located upstream from any water outlet.
b - Where inlet pressure to meter yoke is less than 42 psi, it is acceptable to locate the domestic backflow preventers inside the facility, within 10 feet of water service point of entry prior to any unprotected pipe branching.
SOURCE: Final Rulemaking published at 67 DCR 6148 (May 29, 2020 โ Part 2).
The District of Columbia Plumbing Code (2017), referred to as the โPlumbing Code,โ consists of the 2015 edition of the International Plumbing Code (International Plumbing Code), published by the International Code Council (ICC), as amended by the Plumbing Code Supplement of 2017 (12-F DCMR). The International Plumbing Code is copyrighted by the ICC and therefore is not republished here. However, a copy of the text may be obtained at: https://codes.iccsafe.org/public/document/IPC2015.
District of Columbia Municipal Regulations
Plumbing Code Supplement of 2017
12-F DCMR ยง 603