Section 182.320 - Water heaters(a) A water heater must meet the requirements of parts 53 and 63 of this chapter if rated at not more than 689 kPa (100 psig) and 121 °C (250 °F), except that an electric water heater is also acceptable if it: (1) Has a capacity of not more than 454 liters (120 gallons);(2) Has a heat input of not more than 58.6 kilowatts (200,000 Btu per hour);(3) Is listed under UL 174, UL 1453 (both incorporated by reference; see 46 CFR 175.600 ) or other standard specified by the Commandant; and(4) Is protected by a pressure-temperature relief device.(b) A water heater must meet the requirements of parts 52 and 63 of this chapter if rated at more than 689 kPa (100 psig) or 121 °C (250 °F).(c) A water heater must be installed and secured from rolling by straps or other devices to the satisfaction of the cognizant OCMI.CGD 85-080, 61 FR 986, Jan. 10, 1996; 61 FR 20557, May 7, 1996, as amended at 62 FR 51358, Sept. 30, 1997; USCG-2003-16630, 73 FR 65207 , Oct. 31, 2008