24 CFR 3285.603: Water supply.

(a) Crossover. Multi-section homes with plumbing in both sections require water-line crossover connections to join all sections of the home. The crossover design requirements are located in, and must be designed in accordance with, § 3280.609 of this chapter.

(b) Maximum supply pressure and reduction. When the local water supply pressure exceeds 80 psi to the manufactured home, a pressure-reducing valve must be installed.

(c) Mandatory shutoff valve. (1) An identified and accessible shutoff valve must be installed between the water supply and the inlet.

(2) The water riser for the shutoff valve connection must be located underneath or adjacent to the home.

(3) The shutoff valve must be a full-flow gate or ball valve, or equivalent valve.

(d) Freezing protection. Water line crossovers completed during installation must be protected from freezing. The freeze protection design requirements are located in, and must be designed in accordance with, § 3280.603 of this chapter.

(1) If subject to freezing temperatures, the water connection must be wrapped with insulation or otherwise protected to prevent freezing.

(2) In areas subject to freezing or subfreezing temperatures, exposed sections of water supply piping, shutoff valves, pressure reducers, and pipes in water heater compartments must be insulated or otherwise protected from freezing.

(3) Only heat tape or pipe heating cable listed and certified for its intended purpose is permitted for use, and it must be installed in accordance with tape or cable manufacturer installation instructions.

(e) Testing procedures. (1) The water system must be inspected and tested for leaks after completion at the site. The installation instructions must provide testing requirements that are in accordance with the piping manufacturer's instructions.

(2) The water heater must be disconnected when using an air-only test.