RV Freshwater System Tips

Fresh Water System

Your RV’s on-board fresh water supply is important to your health. Proper care and maintenance is a must.

Use a separate, dedicated drinking water approved hose for your fresh water. Use a different color hose for your utility hose so you will never mix them up. Remember, you will be using your utility hose for lots of things including cleaning the black water tank and sewer hose!

Carry a four, ten and twenty-five foot hose for fresh water hookup. Using these hoses in different combinations makes the right length for most any situation. Having just the right length means no extra hose to coil or have snaking all over the place. The 4ft hose also serves as the RV fresh water tank fill hose at most water fill stations.

When not in use, connect the ends of your fresh water hose together to keep the dirt and creepy crawlers out.

Know your water source. In our travels around the US we generally assume that water is safe to drink. However, RVers have reported filling their water tank with rusty or muddy water from campground taps. And some water, while safe, tastes really bad. Run some water from the faucet into a glass and check for clarity and odor. If the RV park water is not clear or it has an odor you may want to wait until you get to the next place to fill your fresh water tank. When we started RVing we used a water filter on the incoming water supply but now we just filter our drinking water. If the park water has an especially bad taste or is hard we may buy bottled water for drinking.

Keep in mind that filters will remove contaminates such as sand and rust and will improve taste and odor but a filter is not a purifier and will not kill bacteria and other microorganisms.

Before you connect you RV to a curbside faucet check the pressure. Your RV’s fresh water system is designed to operate at pressures of 40 to 70 pounds per square inch. Water pressures at the supply may be much higher… over 100 psi is possible. To protect your plumbing and your water hose you can use a pressure regulator at the faucet end of the hose.

You sometimes do not use our regulator if the park pressure is low in order to get greatest water volume. The problem with not using a regulator is that the park’s water pressure can very. Even if it is safe when you tested it may not stay that way.

How to Sanitize Your RV Fresh Water System

Insuring clean, safe drinking water in your motorhome, fifth wheel or travel trailer requires sanitizing your fresh water system. For a new or new-to-you RV you will want to sanitize before your first use of the system. You may also want to sanitize the system if your RV has not been used for some time, for example if it has been stored for the winter.

The generally accepted method of sanitizing your RV’s fresh water system as outlined below involves filling the fresh water tank with a solution of household bleach and running the solution through each faucet. Then letting it stand for at least three hours. Finally, flush the system once or twice to remove the taste and smell.

This procedure is one you’ll find in most any book about RVing it tried and true but be sure to read on to find out what I do.

Start with a nearly full fresh water tank.

Turn the water heater off and let the water cool.

Dilute 1/4 cup of household bleach for each 15 gallons of tank capacity in to a gallon of water.

Add the chlorine/water solution to the water tank. (Never pour straight bleach into the RV fresh water tank.)

One faucet at a time, let the chlorinated water run through them for one or two minutes. You should be able to smell the chlorine. (Make sure you are using the water pump and not an external water supply.)

Top off the RV fresh water tank and let stand for at least three hours over night is better.

Completely drain the system by flushing the faucets for several minutes each. Open the fresh water tank drain valve to speed up emptying the tank and Open the hot water tank drain plug and drain until it is empty.

Close all valves and faucets and drain plugs.

Fill water tank with fresh water.

Flush each faucet for several minutes each repeating until the tank is again empty. (Make sure you are using the water pump and not an external water supply.)

Fill the tank again. The water should now be safe to drink but if the chlorine odor is too strong you can repeat the fresh water flush.

Your RV fresh water system should now be safe for use.

RV Water Pump

When not hooked up to an external supply, fresh water must be pumped from the on-board RV water tank using an RV water pump. When the power is switched on, the pump works automatically whenever a faucet is turned on. It’s normal for the pump to pulsate. The water pump is preset to keep a more-or-less constant water pressure. When the pump senses a drop in pressure, because you’re using water, it runs long enough to restore the pressure and then shuts off. Depending on the demand for water that pressure can be restored rapidly causing the pulsing.

You can install a device called an accumulator tank that will minimize the pulsating. Also new model RV water pumps are available that claim to eliminate the pulsation and noise.

If your RV water pump is excessively noisy check to see how it’s mounted. The pump’s mounting screws should go through rubber grommets and the screws should NOT be tightened down on the mounting grommets thus allowing the pump to ‘float’ on it’s mounting. This floating helps insulate the vibration of the water pump from the RV’s frame making operate more quietly.

It’s a good idea to switch off the pump when not in use especially when leaving the RV unattended but it is OK to leave it on if you want.

IMPORTANT: If the water pump runs periodically when all faucets are off you have a leak in the water system. The leak may be in the plumbing or it could be in the pump itself. If you are sure that your plumbing is not leaking then the leak is most likely in the pump’s internal check valve. This check value is needed to keep water from flowing back through the pump into the freshwater holding tank when your RV is connected to an external water system. In fact, if you notice that the water level in the freshwater tank is rising it’s good sign that the pump is at fault. There are rebuild kits for most water pumps or, depending on how old the pump is, you may want to replace it.

if your in a park where the water pressure has been very low you can use your water pump to boost the park’s water pressure to take showers. It works because the pump draws additional water from the fresh water tank to supplement that coming from the park.

If the pressure of the water coming from the hook-up is less than the pre-set low pressure of your fresh water pump then water will be pumped from your fresh water tank to increase the pressure to that of the pre-set high pressure of the pump. If you do not want to pump water from your freshwater tank turn the water pump off.

The two most common fresh water plumbing systems are:

1: A hose connection which bypasses the fresh water tank and RV water pump and a separate fill spout used to fill the fresh water tank directly.

2: A hose connection with a valve somewhere near the connection or in a utility area… turn it one way to fill the fresh water tank the other way for direct use.

There is a check valve in the plumbing system that permits the outside water supply to charge the system without going into the freshwater tank. This could be a check valve inside the water pump and it may be the only one or there may also be an external check valve on the discharge side of the water pump.

RV Water Heater

The Water Heater installed in your RV is primarily a propane gas appliance. The water heater installed in most RVs typically has a 6-gallon tank but larger RVs may have 10-gallon units.

Dependent upon the model installed, your RV water heater may operate only on gas or on gas and/or 120 Volt AC.

Your RV water heater may have a gas pilot light which will have to be lit each time you set up camp. Or it may have an automatic, direct spark ignition (DSI) system which allows the water heater to be operated by an electric switch inside the RV.

Your RV water may have a by-pass valve kit installed. The by-pass kit is a popular option that allows for easier drainage of the hot water heater tank and winterization of the unit saving time and reducing the amount of anti-freeze needed. The by-pass kit is installed near the cold water inlet of the water heater and allows for blockage of water flow into the water heater.

All water heaters in recreational vehicles are equipped with a pressure relief valve that is designed to open if the temperature of the water within reaches (210 degrees F) or if excessive pressure builds up.

When the water supply pressure reaches 50 pounds per square inch (PSI), the relief valve will open and water will drip from the valve. The valve will close automatically once the pressure falls below 50 PSI. This dripping is normal and does not indicate a malfunctioning or defective valve.

Also, when water is heated it expands and pressure can become greater than 50 PSI within the closed water system of the recreational vehicle and this will also cause weeping at the pressure relief valve.

One way to minimize relief valve weeping is by maintaining an air pocket at the top of the water heater tank. The air pocket forms naturally by design but will reduce overtime through normal use.

Sacrificial Anode Rod

Most RV water heaters have a sacrificial anode rod within the tank increases the life of the tank and under normal use will deteriorate. The anode rod should be checked yearly or more frequently if water supplies contain high levels of iron or sulfate and replaced as necessary.

Exterior Door Screen

Another important maintenance procedure is periodically checking the water heater screen in the exterior door for any obstructions, such as animal /insect nests or debris. Proper ventilation is essential to the safe operation of the water heater.

Check for Soot

If soot is present anywhere, shut the unit down until it can be repaired. Soot is a sign of incomplete combustion and should be corrected before operating the water heater. A qualified technician should do any repairs that need to be performed.

RV Water Heater Pressure Relief Valve

Weeping or Dripping As in residential water heaters, the water heater equipped in recreational vehicles contain a pressure relief valve that is designed to open if the temperature of the water within reaches 2 0 degrees F or if excessive pressure is built up. When pressure reaches 50 pounds, the relief valve will open and water will drip from the valve. The valve will close automatically once the pressure falls below 50 pounds. This dripping is normal and does not indicate a malfunctioning or defective valve.

Also, as water is heated it expands and with the closed water system in a recreational vehicle, water expansion will cause weeping at the pressure relief valve. One way to minimize this weeping is by maintaining an air pocket at the top of the water heater tank. The air pocket forms naturally by design but will reduce overtime through normal use.

Replenishing the Air Pocket

  1. Turn off water heater.
  2. Turn off cold water supply.
  3. Open a faucet in the RV. to relive pressure.
  4. Allow time for water to cool and Pull out handle of the Pressure Relief Valve and allow water to flow from the valve until it stops.
  5. Release handle on valve… it should snap shut.
  6. Close faucet and turn on cold water supply, as tank fills, the air pocket will be replenished.

Draining & Storage RV Water Heater

When not using RV water heater for long periods such as storing the RV during the winter months, the water heater should be drained to avoid damage from freezing during the winter and / or deterioration of tank life from mineral content in water supplies.

To Drain the Water Heater

  1. 1.Turn off power to the water heater at the switch or the main breaker.
  2. Shut off the gas supply and the water pump.
  3. Open all fixtures, both hot and cold throughout the unit.
  4. Place the bypass valve (if equipped) in the “by-pass” position.
  5. Remove/open the exterior access door to the water heater.
  6. Remove the anode rod from the tank. Water will drain out tank.

Water Supply & Odor

Water supplies sometimes contain high levels of sulphur, which causes an unpleasant smell, similar to rotten eggs. While unpleasant, the water is not harmful. Sanitizing the water system, as described earlier and allowing the sanitizing solution to remain for a few days, should eliminate the odor. Remember to thoroughly flush the system after sanitization. Adding a filtration system will help reduce such occurrences.

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