By Russ and Tiña De Maris
RV water pumps can be aurally disturbing. The little motor that fires up when you open a tap or flush the toilet can make plenty of noise. But when there’s no “demand” for water, your RV water pump should be the soul of quietude.
Water pump noises when there’s no demand for water could mean you have a water system leak. That’s a real issue, not only from wasting water, but because leaks can quickly do serious damage to your rig.
What we found
We once had a travel trailer that we liked to dub “a project rig.” In the wife’s mind, it was a never-ending project that constantly threw open new opportunities to expand my repair skills.
Lying in bed one night, our slumbers were disturbed by a periodic “purrummp!” noise. We’d just about get to sleep when that “purrummp!” would punctuate the otherwise stillness of the night. Yep, that was decidedly a water pump noise.
In the end, we found two “leakers.” The first was a city water inlet that was dripping when under pressure. Easy enough. The second, the water containment shell of our water heater, had given up the ghost. More complicated, and far more expensive.
What if you hear the noise?
So what do you do if you hear the dreaded water pump noise, your personal “purrummp!”? It’s time to get detecting with an eye to fixing whatever is leaking. For us, it was a matter of finding the “farthest out” connection on the plumbing line.
When you get there, check every fitting, every inch of water line. In most cases, water pump noises indicating a leak will point to a loosened or bad fitting—not a leak in the line itself.
Working back toward the pump, check it all out. Galley faucets, bathtub shower control, toilet, bathroom sink, and all the little fittings along the way.
It’s no mean feat: While it’s true the RV construction “code” requires that you have access to all plumbing lines in the rig, getting at them may require hiring a moving company to clear out closets, and formal training as a contortionist to wiggle into places no self-respecting rat would climb into.
You may find telltale stains, particularly if the leak has been around for a while. But your fingers, carefully feeling each connection, will probably point you to the leak.
Some are more mysterious than others
In some cases, that water pump noise just doesn’t seem to jibe with a leak. On a recently acquired travel trailer, we heard the “purrummp!” and were convinced we fixed the problem—a water heater fitting that had loosened up. But shortly after tightening it, here came that haunting pump noise again.
Outside, we located a suspicious dripping under the rig, near the wastewater dump valves. We initially thought it was perhaps a leaky holding tank, but with the “purrummp!” noise, it didn’t tally up. Checking the smell of the drip didn’t point to either black or gray water—both of which have a particular smell. Definitely fresh water. What could it be?
We finally found the culprit when parked slightly off-level. A small stream of water rolled out from under the toilet and across the floor. In this case, a bad toilet valve was allowing a bit of pressured water to leak on the floor under the toilet.
When parked on the level, the water ran under the toilet, down into the rig’s underbelly, eventually dripping out onto the ground. Had we not been off-level, we would probably have gone crazy trying to find the leak.
New to RVing? Your adventures won’t all be where the road takes you—some could be inside the rig, acting out the role of Sherlock Holmes and the Case of the Water Pump Noise.
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RVDT2852
One of the FIRST things you do when you hear the noise at night, is turn OFF the pump! (I make it a habit of turning it off at night anyway). I have no leaks of course, but in the past I had a toilet water line come loose and drip. Using your phone to reach behind tight areas was a big help in finding that!
Agreed. An intermittent pump run with no open valves is a cause for investigation. But what if you cannot find anything? A common problem is the pump’s check valve. The pressure could be lost pushing water back into the fresh water tank – not a leak. You filter (at least most do) your city water entering the system. How many also filter the water going into the fresh water tank? Just a teeny tiny speck of grit could be lodged in the pump’s check valve.
Also agree with Ran, we turn off the water pump when not using water.
In having worked quite extensively on my RV plumbing, I must ask the question: Does the RV industry know about the “code” that requires access to all plumbing lines in the rig? Some lines are buried so deep you not only can’t access them, you can’t even see them.
The water lines may initially be run in ways they are accessible. But then cabinets, shelves, furnace and flexible duct work and drain lines are installed. You can see the lines but working on the them is near impossible.
If you do not find a leak, check that there is no air in the lines. Air in a little used line, like an outside shower, can cause the pump to cycle.
There are causes other than water line leaks. Make sure that the stopcocks on your drain lines are really in the off position. I replaced a water pump only to find that the problem was a stopcock position. Replacing the water pump is easy, but look for other causes first. Depending on how your fresh water valve is designed, it could be diverting water or allowing air to get into the system. Don’t forget to check your outside sprayer faucet in the service bay and make sure it is off. If you have a washing machine in your RV, look very closely at its shut-off valves while connected to city water or with the pump on. Ours were plastic and one had cracked.
I’ve spent months worrying and looking for leaks. I think I found it. If your pump is 3-4 yrs old start there. I found evidence of a leak on the pump where the pressure sensors live. It wasn’t wet but was leaking a little from time to time. Calcium or some white dust like residue. May have been letting air in. The new pump seems to have fixed it.