609.10 Disinfection of Potable Water System — 2025 California Plumbing Code

New or repaired potable water systems shall be disinfected prior to use where required by the Authority Having Jurisdiction.

[OSHPD 1, 1R, 2, 3, 4 & 5] Prior to utilization of newly constructed or altered potable water piping systems, all affected potable water piping shall be disinfected using pro- cedures prescribed in California Plumbing Code Sections 609.10(1) through 609.10(5). The method to be followed shall be that prescribed by the Health Authority or, in case no method is prescribed by it, the following: (1) The pipe system shall be flushed with clean, potable water until potable water appears at the points of the outlet. (2) The system or parts thereof shall be filled with a waterchlorine solution containing not less than 50 parts per million of chlorine, and the system or part thereof shall be valved-off and allowed to stand for 24 hours; or, the system or part thereof shall be filled with a water-chlorine solution containing not less than 200 parts per million of chlorine and allowed to stand for 3 hours.

(3) Following the allowed standing time, the system shall be flushed with clean, potable water until the chlorine residual in the water coming from the system does not exceed the chlorine residual in the flushing water.

(4) The procedure shall be repeated where it is shown by a bacteriological examination made by an approved agency that contamination persists in the system. (5) [OSHPD 1, 1R, 2, 3, 4 & 5] Disinfection shall be com- pleted no more than three weeks before whole or partial beneficial occupancy.

(a) Where occupancy is delayed two weeks from disin- fection, flushing of all fixtures shall again be com- pleted.

(b) Where occupancy is delayed four weeks after disin- fection, disinfection and flushing shall again be com- pleted.