12 Gallon Suburban Water Heater Direct Spark and Electric Ignition The SW12 Series has all the features of our popular SW10 Series, plus increased capacity. It includes our two year parts and labor limited and third year tank limited. Using the same cut out opening, you get two additional gallons of hot water with the highest tank capacity in the RV industry. More hot shower time and more hot water for domestic use. Same sidewall cut outs as the 10 gallon models. Only 1 3/4" deeper than current 10 gallon models. Direct spark ignition models available. Optional electric element and motor aid with steel glass lined tank with a node rod protection.