Tuesday, November 28, 2023


Water pump noises could mean leaks in your RV’s water system

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 do you do?

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.

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 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 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?

R&T De Maris

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 been 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 roll of Sherlock Holmes and the Case of the Water Pump Noise.


Russ and Tiña De Maris
Russ and Tiña De Maris
Russ and Tiña went from childhood tent camping to RVing in the 1980s when the ground got too hard. They've been tutored in the ways of RVing (and RV repair) by a series of rigs, from truck campers, to a fifth-wheel, and several travel trailers. In addition to writing scores of articles on RVing topics, they've also taught college classes for folks new to RVing. They authored the book, RV Boondocking Basics.



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Sharon B (@guest_205743)
1 year ago

I am traveling and live in my 2014 Keystone Laredo fifth wheel. It was purchased a year ago. Had no issues with water flow ever. However, I stayed at a campground for 5 months in the desert and my water flow became unusable. I always use a pressure regulator and bought another one thinking it was clogged. In checking the hose connection to my rig was stuck. It took time and elbow grease to remove it only to find it was filled with a white goop. I had to soak the connections in CLR solution over night and then scrape off the white stuff. That has never happened to me in my smaller travel trailer or this 5th wheel until I stayed at this campground. Yes, I also changed the water filter at the post. Even though everything on the outside is clean, I still have lousy water pressure making me use the water pump. That pressure is normal. I am trying to find out if there is another filter somewhere I cannot see. If there is one I need to know. Please help.

RV Staff
1 year ago
Reply to  Sharon B

Hi, Sharon. I’ve forwarded your comment by email to Dave Solberg, one of our RV tech experts. (I’ve scheduled it to send tomorrow a.m., since it’s later where he is and I don’t want to bother him on a Sunday night.) Anyway, hopefully he can answer your question or at least point you in the right direction. Good luck! 😀 –Diane

Dave Solberg
1 year ago
Reply to  Sharon B

What you are experiencing is calcium and lime build up from the hard water at the campground. Not sure what filter you are using, however it needs to be a very fine one and they will typically clog up fast. If the water is really hard, you might need a double filter. Since you are still having pressure issues, I would believe the check valve in your city water connection is also clogged. Take a look at the connection where you install the water hose. You should see a small tab that is spring loaded. This is a check valve to keep water from backflowing out of the rig when you use the on board pump. You should be able to push the tab in to allow water to flow through. You might need to remove and clean or replace this.


John (@guest_205601)
1 year ago

No mention of a common issue, a faulty check valve (usually internal to the pump). Allows pressure in the line to drop a little, pump kicks on and raises the pressure back, then shuts off. We had this, I installed a check valve in the line from the FW Tank to the pump suction side, problem solved. A side note on this problem, it is often accompanied by your FW Tank filling up when on City Water, we had that happening as well.

Neal Davis (@guest_205444)
1 year ago

All great advice; thank you! I do want to reiterate the importance of paying attention to the sound(s) the water pump makes. Ours was essentially silent (as perceived from the bathroom) when it was “on,” but there was no call for water. It became audible when calling for water. I noticed that the sound level for both situations increased and investigated. I discovered a water drip when the pump was “on” and a trickle of water when there was a call for water. However, I could not identify the source of the renegade water. I scheduled a visit to our service shop so they could identify and address the leak. The leak was not a loose fitting but a harbinger of the pump failing. Noises matter, pay attention to them!

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