(A) Each new water main extension shall be flushed, pressure-tested, and disinfected. No flushing, pressure-testing, or disinfection shall take place until the Water Superintendent, or his or her designated representative, is notified at least 48 hours in advance of flushing, pressure testing, or disinfecting.
(B) When flushing new mains, the city shall provide a pressure gauge and connection to an adjacent main to be monitored during flushing operations. At no time during any flushing operation shall pressure on the city main drop below 20 psi.
(C) The water main installed shall pass the hydrostatic pressure test defined below, as a minimum, prior to final acceptance by the city. The contractor will be permitted, at his or her option, to backfill completed sections prior to testing. However, he or she shall notify the Water Superintendent 48 hours in advance before backfilling if he or she wishes to exercise this option.
(D) It is called to the contractor’s attention that the costs for locating leaks, excavation, repair, replacement, and re-testing of sections failing to pass the pressure test shall be borne by the contractor.
(E) During testing, the pipe shall be slowly filled with water, care being taken to expel all air from the pipes. If necessary, the pipes shall be tapped at high points to vent the air. Permanent air-release valves may be required on specific projects.
(F) (1) Pressure 50% in excess of working pressure, as measured at the point of lowest elevation, shall be applied for not less than two hours for testing of exposed sections of piping; and six hours for sections of piping that have been previously backfilled prior to testing.
(2) All exposed piping, fittings, valves, hydrants, and joints shall be carefully examined for defects. Leaking joints shall be remade and then retested.
(3) The minimum test pressure shall be 120 psi. The required test pressure shall be maintained for the full duration of the test by adding/pumping water into the main.
(G) No pipe installation will be accepted unless and until the leakage, determined under the specified test pressure, is less than computed with the following formula.
L = ND (P)0.5 7,4000 L = Allowable leakage gallons per hour N = Number of joints in line being tested D = Nominal pipe diameter inches P = Average test pressure, PSIG |
(H) Disinfection by the contractor of the installation shall conform to the specifications as approved by State EPA, Division of Public Water Supplies. As a minimum, the disinfectant dosage shall be 50 mg/l of chlorine, in contact for at least 24 hours, and having a minimum of ten mg/l chlorine residual at the end of the 24-hour period. Disinfection shall not take place until the lines have been flushed and satisfactorily pressure-tested.
(I) While the disinfectant dosage is present, each valve and hydrant shall be exercised to bring wetted parts into contact with the disinfectant solution.
(J) All chlorine residual tests shall be conducted using the DPD method as outlined in Standard Methods.
(K) (1) After the disinfectant has been in the main for 24 hours, the main shall be flushed until the chlorine residual at the extremity of the addition is equivalent to the chlorine residual in the city supply main. After that flushing has been completed, the isolation valve to the city supply main shall be closed, and the contractor shall collect water samples for bacteriological analysis by a laboratory certified for such work by the state.
(2) Bacteriological results must be satisfactory on samples collected 24 hours apart on two consecutive days. The sampling points and number of samples at each point shall be as specified by State EPA, Division of Public Water Supplies, or as specified by the city.
(L) Bacteriological sampling should not commence after Wednesday or before Monday if EPA does the bacteriological tests. This is necessary due to the fact that a minimum of 48 hours is required for the necessary bacteriological testing.
(M) Samples shall be taken from smooth-nosed sampling taps or from copper piping connected to the new main through a corporation stop. No bacteriological samples shall be collected from fire hydrants.
(N) After the bacteriological samples have passed on two consecutive days of testing, the contractor shall deliver the completed State EPA, Division of Public Water Supplies, operating permit application to the city. The operating permit will be mailed after all conditions have been met and the city is ready to assume ownership of the lines.
(1978 Code, § 13.06.150) (Ord. 538, passed - -1979)