Fresh Water
An RV water system is made up of the following components:
Fresh water hose, connected to an external water source
Fresh water tank
Water filter
Pressure regulator
Water pump
Water heater
City Water
City water, or external water, comes through a hose connected between the campground water and your rig. The water pressure at the tap is controlled by external forces - there’s nothing you can do to control the amount of pressure coming from the tap.
Run the water at the tap for 15-30 seconds to flush any minerals, rust or debris and check for good pressure before hooking up the water hose.
Use a hose specifically made for drinking water, and replace the hose every couple of years. Drinking water hoses are usually white and come in 25, 50 and 100 ft. lengths. Two or three shorter hoses work better than one long hose. Use the length necessary and it’s a lot easier to coil up and stow a shorter hose.
It is usually not necessary to run the water pump when connected to city water.
On-Board Water
When not connected to city water, the on-board water stored in the fresh water tank may be used by turning on the water pump. The pump will pressurize the system and will make some noise when water is being used, which is normal. If you’re not using water and the pump is running, start investigating for the possibility of a water leak somewhere inside the rig.
The fresh water tank has a vent or overflow tube that drains to the ground when the tank is full. It also has a low-point drain with a valve, which is the lowest point in the RV water system.
There is no problem traveling with fresh water in the tank. This allows the convenience of using the bathroom, shower or sink when not hooked up to city water. Just be aware that water weighs a little over 8 lbs. per gallon, so a 100 gallon fresh water tank adds over 800 pounds to traveling weight.
It’s important to sanitize the internal water system, usually once a year. Here is a good step-by-step process for sanitizing the system.
HOT WATER HEATER
Courtesy RV Repair Club
RV water heaters are made by one of two companies - Suburban and Atwood.
Heaters have two methods for heating the water: an electric heating element or propane gas. Switches at or near the main control panel give the option of “Off”, “Gas”, or “Electric”. There was a time that RV manufacturers didn’t do a good job labeling the switches inside, so it was trial and error to figure out what each switch controlled. Newer models make it much easier and are self-explanatory.
It is easy to damage the electric side of the system. If the water heater is turned on one time without water in the tank, it will burn out the heating element.
There is also a black rocker switch on the water heater that seems to be the weakest link of the electrical system. That switch can overheat and melt, either because of electrical load or its proximity to very hot surfaces in the heater. When it overheats, it can cause gremlins in both the electrical and gas side of the heater. In some heaters, the rocker controls power to the propane ignition starter; other heaters use it to control electric power to the element.
Why electric and propane? The gas side of the water heater ensures that you can have hot water even when you’re not plugged in to campground power. Since it heats by flame, it takes less time to refresh and the water usually gets hotter. The downside is that the propane is coming out of your tanks, which is ultimately costing you money.
The electric side of the water heater runs off of 120 volts AC so only works when plugged in to shore power. When the electric side is working properly, the hot water will be fine for showers and washing dishes. It does take a little longer to refresh when the hot water supply is used up, but the heater is running off of campground power, typically at no additional cost. We use the electric side of the water heater as often as possible.
Corroded water heater element and anode rod
Water heater maintenance. The water heater must be turned off completely before performing any maintenance. Turn off the gas, turn off the electric, and turn off the black rocker switch on the heater before draining the water. If the heating element is energized without being submersed in water, it will immediately burn out and the element will need to be replaced in addition to whatever maintenance was planned.
The anode rod is designed to corrode so that other metals in the water heater tank don’t. Its life span under normal conditions can be a couple of years or less, depending on the quality of the water.
The tank should be flushed at least annually by removing the anode rod. If the rod shows significant corrosion, replace the rod. The heating element generally doesn’t need to be inspected unless the water is not getting hot.
The anode rod should look bad - that means it’s doing its job.
If the heating element has significant corrosion, it will lose its heating ability and take longer to heat the water. It also may not get as hot as normal.
Water Filters and Softeners
Your RV will probably have at least one internal, or “house”, water filter. It’s usually a canister type filter and will be located in the basement area, either in the convenience center (same location as tank pull-valves and hookup area for water, cable, etc), or behind the basement wall through an access door. This filters all water, both city and on-board water, and should be changed about about every 3 to 6 months.
Internal, or “house” filter
It is wise to add the common blue in-line Camco filter and a pressure regulator to the end of your fresh water hose. This filters the water before it ever enters your water system, and the pressure regulator ensures that water will enter your rig at a safe pressure that won’t stress the plastic fittings. Generally 65 to 75 psi is a good setting for incoming water.
Several areas of the country have moderate to very hard water, caused by high calcium and magnesium levels. Even though hard water is safe to drink, it can cause stains and premature failure of water heater elements. Hard water can be treated with a water softener, and RV water softeners can be external units that are hooked up in line with city water, or permanently installed in the basement area.
