Freshwater RV tanks hold the water used in sinks, toilets and showers. The size of freshwater tanks can vary depending on the size and layout of the RV and they can hold anywhere from 20 to 1000 gallons of water. 

There are many situations where you may find yourself not connected to potable water sources or the sewage system. Boats and RVs are two common examples. For RVs, you need three different types of tanks: a freshwater tank, a greywater tank and a blackwater tank. 

Greywater tanks are where the water used in sinks and showers goes. These tanks are typically small, holding about 50 gallons of wastewater. Used toilet water goes to the black water holding tank. Like the other two kinds of RV tanks, the size of black water tanks can vary depending on the size and layout of the RV, but they generally hold 40 to 70-gallons of waste. 

There are also a number of different slip fittings to connect the RV tanks to the proper hoses and other tank accessories, including pump-out kits and vacuum relief valves.