Written by Johnathan R. Smith• March 2, 2019• 9:00 pm• Common Questions

RV Water System Troubleshooting (Common Pump Issues)

RV Water System Troubleshooting

Whether RVing is your lifestyle or a part-time hobby, repairing the broken systems on your unit is never fun. It’s worse if you have absolutely no knowledge about what you are working on. This article is about troubleshooting your RV water pump system, and we’ll help you learn a little more about how this system works.

The RV water pump is vital for any of your water needs whether it’s the shower, sink, or toilet. We’ll address common problems that you likely run into at some point in time and how the water pump works. They’re relatively simple once you understand the basics.

General Information on RV Water Systems

All RVs have a wastewater and a clean water system. The wastewater is referred to sometimes as black water while the clean system provides you with potable water and is sometimes known as gray water. The colors are references to the tanks that each water system uses for storage. These systems give you fresh water and eliminate the used water inside your RV.

Maintaining your RV’s water systems before, after, and while in use will significantly reduce the number of problems that you have with it. This maintenance includes winterizing it when you’re not using the RV.

The Water Pump

First of all, locating the water pump may be the trickiest part of troubleshooting. For some reason, RV manufacturers tend to hide them despite knowing that you need access to them. To find it, you can turn the pump on and follow the distinct noise that it makes.

The water pump on an RV is an on-demand system. So, it only cuts on when needed. A water pump pressurizes your water pipes to a specific preset PSI or pounds per square inch. 30 PSI is standard, but many pumps can be adjusted.

Water pumps almost always run on 12-volt DC power. Even if you plug your pump into 120-volt AC (alternating current) in a campground, the converter changes the AC power to DC (direct current) power to run it.

Once the power to the pump is turned on, it begins pumping. As long as any faucets are on, the pump runs continuously providing the essential water flow. After you turn the faucet off, the pump will continue to run until all of the water pressure builds up in the water lines again.

When the preset water pressure is reached, the pump shuts off automatically. The pressure in the plumbing line remains the same until you turn on the faucet again then the water pump senses the pressure drop in the water lines and starts pumping again to maintain it.

Older RV pumps work a little differently. They must be turned on manually when you need water. First, you open the faucet and then turn on the pump for water. To stop the water, you turn the pump off and then close the water faucet.

Completing these actions in this order is crucial. Older pump technology dictates this specific order. They don’t turn off after the water in the pipes reaches the predetermined water pressure. If you leave older pump’s on, they’ll burst a water line, or the pump will overheat.

Maintaining Your RV Water Systems

Before we go into troubleshooting water problems, let’s discuss maintaining your systems to reduce issues with them.

Tips for Gray and Black Water Tank

Black Water- This tank holds the wastewater from the toilet. Don’t dump this tank anywhere but your home septic tank or a pre-approved RV dump area. Always leave the valve closed on the black water tank, even when you’re hooked up at an RV site. Keeping the valve closed allows time for the solids to break down before dumping and prevents you from leaving behind any waste accidently. It also helps prevent odors from the septic system from rising into the living area.
Gray Water- This water comes from the showers and sinks. The valve for the gray water is easy to recognize because it is a smaller pipe around 1.5 inches in diameter. You should dump this water last to clean the hose.

Sanitation

Water in the RV may become stale over time. The tanks can also take on an odor. It’s important to sanitize and clean the fresh water tank regularly. To clean it, add a cup of bleach for every 15 gallons that the container can hold. Then fill it with water.

Next, switch on the pump and open up every faucet in the RV until you smell the bleach. After that, drain the water system and run fresh water through the taps again until you no longer smell bleach.

Hoses

You shouldn’t connect an ordinary garden hose to a water source. Purchase one that is specifically designed for fresh drinking water. These hoses are usually white, and lead and BPA free with no rubbery or plastic taste. Wind the drinking hose up when you’re not using it and hook the ends together. Make sure that you store it separately from the sewer hoses.

Winterizing

If you store your RV during the winter, you must properly winterize the whole water system, including draining out all the water and adding antifreeze or blowing out all of the water lines. If you add antifreeze, turn on all of faucets to open the lines until antifreeze runs out of the taps.

You need to winterize the water heater also. Drain and close the bypass valve, or you’ll need up to 10 more gallons of antifreeze.

Don’t open the drain plug on the water heater while it’s hot when you’re winterizing or sanitizing the water system. Turn it off and let it cool down before you open it.

Troubleshooting Problems with Your Water Pump

Here are some common water pump problems that you may experience and how to troubleshoot them.

The Pump Sounds Like its Running, but No Water is Coming Out of the Faucets

If you hear your pump running but there’s no water coming out there could be several issues.

Clogged in-line filter
Low water level inside the tank
The pump is running backward.
Clogged water lines
Worn or damaged pump impeller
Suction line kink
Inoperative pump-drive belt
The hose clamps may be loose on the suction side of the water pump.
The backflow valve could be stuck.
The pump-check valve may be stuck.
Fractured pump housing
Punctured diaphragm

First, you should check the freshwater tank to make sure there is water in it. Check the gauge on your tank. If the water level is low or the tank is empty, the water pump won’t work. If your tank is full, look at the water lines leading into and out of the pump itself.

Are the connections loose?
Are the lines crack, wore, or split?

Begin with the line that goes into the fresh water holding tank. After that, check the water lines that go into the tank and lead up to the RV.

Then you need to figure out if there is any water flowing into the water pump. To do this, you’ll loosen the line to the pump. If you find water inside the line, this means that water is going into the water pump. Simply reconnect the water line. If the line is dry, the issue should be with the water line from the pump to the tank.

Next, check for tube damage or blockages then refill the line with water to re-establish suction. Connect the water line to the pump again and see if water starts moving towards the faucets. This process may take a few minutes so have someone else monitor the taps to let you know whether the water begins flowing or not.

Still no water? Well, now it’s time to look at the pump itself to see if you need a whole new unit or if it needs a new motor. You can do this by having someone stand by the switch for the water pump to turn it on and off when you need it.

Next, disconnect the line from the pump on the pressure side. Place a bucket under the opening and turn the pump on to see if water pumps out. If it does, does it drip or flow out?

If it just trickles, you need a new pump, but if the water seems pressurized, then the issue lays somewhere between the RV faucets and the water pump.

It becomes more complicated after this, and some people run out of patience. You can always hire a plumber to evaluate the problem or call the RV manufacturer. With some of the other issues above you may need to replace parts such as the belt, impeller, screen to the in-line filter, element, pump wiring, etc.

I Can’t Get the Pump to Work this Year After Winterizing it Last Year

This problem is common and frustrating. Check these following things:

Did you accidentally leave the drain open when you were trying to fill up the water tank?
Was everything re-connected correctly after you put antifreeze in last year?
Check to see if the shut-off valves are open.
Can you hear the pump? If not, check to make sure the electricity is working. You can check the electrical panel to see if you blew a fuse or the breaker tripped.
If you have a voltmeter, make sure that there is voltage going to the pump and make sure that its grounded.
If all else fails, you may need a new water pump.

The Pump Cycles On and Off with the Faucets Turned Off

Possible causes for this issue could be a malfunctioning toilet valve, leaking faucet sets, a water leak somewhere in the plumbing, a defective pressure switch, or a leak inside the valve. For a leak in the plumbing, you would need to locate and fix it.

If its leaking faucet sets than they should be repaired. If it’s a malfunctioning toilet valve, just repair it. An internal valve leak requires you to put in a pump-repair kit. Simply replace the pressure switch if it’s broken.

The Pump Motor Doesn’t Run

This water pump problem is also common and has several possible causes. It could be as simple as a blown fuse which you can quickly fix. Once you locate the blown fuse replace it.

The master switch may be turned off and if that is the case you just need to switch it back on. The battery may also have a low charge. Simply charge the battery, and the pump motor should run again.

A loose connection in the wiring may also keep the water pump motor from running. In this instance, check all of the connections. The pump also won’t run if it’s not grounded or poorly grounded. Re-check this connection and ground it properly if this is the problem.

You may have a broken or defective motor, and you need to replace it to run your water pump.

Conclusion on Water Pump Troubleshooting

These water pump problems are just a few of the usual issues people have with the water system in their RVs. Other issues include loud pump noises and vibration, a leaking water pump, the pump fails to shut off, inadequate water pressure or flow, the pump won’t prime, the water flow sputters, and more. The water systems in an RV aren’t overly complicated but finding the problem can be frustrating.

Often, adequately maintaining your system eliminates many water system issues that could occur. Of course, there is no protection against general wear and tear or age. Many people invest more money to purchase a newer RV, so they won’t have to deal with as many of these issues. However, new RVs are very expensive.

If you’re somewhat mechanically inclined and don’t have the budget for a new RV, purchasing a used one in good shape is a great idea. After all, no one can completely avoid any maintenance issues forever. Even new RVs come with their fair share of problems. Use these maintenance and troubleshooting tips to get you back to vacationing in your RV quicker and with less stress.

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About the Author / Johnathan R. Smith

I am a well traveled Marine Corps veteran that enjoys the outdoor and nomadic lifestyle that RV living provides. I am also a member of the National RV Inspectors Association (NRVIA.org). As the founder of Camperguide.org my goal is to provide you with well researched information so that you can enjoy the best of the RV lifestyle.

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