18-29-606.5.3 Check valves required.
   Check valves which are noiseless in their operation and air chambers of sufficient air cushion capacity shall be installed in the suction pipe and the discharge pipe of each house pump, or other water pressure increasing device. Where such check valves are of the slow-acting type and the operation thereof entirely eliminates the shocks, strains, stresses, and excess noises caused by the operation of such pump or device, the installation of air chambers may be dispensed with.