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  1. Water service piping and hot and cold water distribution piping in new or renovated potable water systems shall be disinfected after flushing and prior to use.
    EXCEPTION: Single dwelling units with public water supply.
  2. The procedure used shall be as follows or an approved equivalent:
    1. All water outlets shall be posted to warn against use during disinfecting operations.
    2. Disinfecting shall be performed by persons experienced in such work.
    3. The water supply to the piping system or parts thereof being disinfected shall be valved-off from the normal water source to prevent the introduction of disinfecting agents into a public water supply or portions of a system that are not being disinfected.
    4. The piping shall be disinfected with a water-chlorine solution. During the injection of the disinfecting agent into the piping, each outlet shall be fully opened several times until a concentration of not less than 50 parts per million chlorine is present at every outlet. The solution shall be allowed to stand in the piping for at least 24 hours.
    5. An acceptable alternate to the 50 ppm/24-hour procedure described in Section 10.9.2.b.4 shall be to maintain a level of not less than 200 parts per million chlorine for not less than three hours. If this alternate procedure is used, the heavily concentrated chlorine shall not be allowed to stand in the piping system for more than 6 hours. Also, special procedures shall be used to dispose of the heavily concentrated chlorine in an environmentally acceptable and approved manner.
    6. At the end of the required retention time, the residual level of chlorine at every outlet shall be not less than five parts per million. If the residual is less than five parts per million, the disinfecting procedure shall be repeated until the required minimum chlorine residual is obtained at every outlet.
    7. After the required residual chlorine level is obtained at every outlet, the system shall be flushed to remove the disinfecting agent. Flushing shall continue until the chlorine level at every outlet is reduced to that of the incoming water supply.
    8. Any faucet aerators or screens that were removed under Section 10.9.1 shall be replaced.
    9. A certification of performance and laboratory test report showing the absence of coliform organisms shall be submitted to the Authority Having Jurisdiction upon satisfactory completion of the disinfecting operations.

Related Code Sections

10.9.2 Water Supply and Distribution Systems, Disinfecting
Water service piping and hot and cold water distribution piping in new or renovated potable water systems shall be disinfected after flushing ...