RV Water System Components
Most modern RV water systems use a plastic water storage
tank of between 20 to 50 gallons of potable water with a hose leading to an electrical demand type
water pump. The tank is normally equipped with a valve or plug to allow the tank to be completely
drained for winterizing.
- Water storage tank
- Water lines
- Terminal components
- Waste removal
- Demand pump
- Compressed air systems
- City water connection
The operation of the demand type water pump is automatically
controlled by a pressure sensitive switch that shuts off the pump when the system pressure reaches
a preset limit. When a tap is turned on, the resulting water flow reduces the system pressure
causing the pressure switch to turn on the pump thereby maintaining the system water pressure. When
the tap is turned off, the pump continues to run for a few seconds until the system pressure is
built up to the preset limit, whereupon the pressure switch again turns the pump off. All
components located beyond the demand pump are part of the pressure side of the water system.
In most recreational vehicles, immediately after the water
pump, is the "city" water inlet which is a connection to allow the system to use the water and
pressure from an external water source. (i.e. the faucets supplied in an RV park etc.)
The pressure side of the water system consists of the
various distribution lines, the hot water heater (if so equipped) and the terminal points of the
system. (Sinks, shower, toilet etc.)
Beyond these points is the waste water removal system - all
of which must be protected from freezing and the resulting damages, as will be described later.
In some RV's, especially older models, an air compressor
takes the place of a pump - the compressor forces air into an air tight water storage tank and it
is this air pressure that forces water through the lines whenever a tap is opened.