Why Does My RV Water Pump Pulsate When Not in Use and How to Fix It? 

When it comes to your RV, there are plenty of inconvenient and annoying things that can happen. From flat tires and power surges to not having proper sway control or weight distribution, RVing is a complicated endeavor. However, one of the more troubling and annoying issues is having a water pump that’s pulsating, even when you aren’t using it. 

Your RV water pump is pulsating when not in use because you likely have a water leak. Water leaks can develop in your water lines, your freshwater tank, from the pump itself, or on one of your plumbing fixtures. The only time your RV water pump should pulsate is when you have the water running.

While it’s perfectly normal for water pumps to pulsate when you’re using water, it’s not normal for them to cycle on or off when the water is turned off. A pulsating pump without the use of water in your RV is an indicator that you’re losing water somewhere, which causes the water pump to activate and regulate pressure. 

What is the Job of an RV Water Pump? 

RV water pumps, like water pumps in a house, are installed to maintain water pressure. They help push or force water through your plumbing lines to reach its destination, which can be your bathroom, kitchen, or laundry room. Essentially, anytime you open a faucet or start a washer, your water pump’s job is to push the water in that direction. 

Because the water pressure at most campgrounds is sufficient to get water where it needs to go, you often don’t need your water pump. The only time you do is if the pressure is extremely low, or if you are using water out of a fresh water tank. If water is coming from your fresh water tank, it’s sitting still and needs the water pump to propel it forward. 

Why is My RV Water Pump Pulsating When I Don’t Use Water? 

Now that you understand how water pumps work and what they do, you realize they should only operate at certain times. Therefore, if you aren’t using your water but you hear the pump activate, it means that water is getting sent somewhere without your permission. Here’s why that happens and what you should do. 

Leaky Water Pipe 

The first possibility is that you have a slow pressure leak in one of your plumbing pipes. Leaky pipes can happen when you let water freeze inside the pipes, excess water pressure, or a plumbing error during construction. No matter what’s causing the leak or where it is, however, you’ll have to deal with the problem and repair the leak. 

How to Fix

The first step to fixing a leaky pipe is to determine where it is. You can check your floor for water damage, which would be a sad but good indicator. If necessary, you can also crawl under your RV and remove the protective cover and insulation on the bottom. With some inspection, you should be able to spot the leaky pipe. 

To repair a leaky pipe on your RV, ensure that the water is turned off. Use a pipe cutting tool to make a neat cut on either side of the leak. Install couplings and a small piece of pipe the appropriate length to replace the damaged portion. If the leak is happening at a fitting, you can follow the same process and install a new fitting. 

Leaky Toilet, Faucet, or Fixture

It’s also possible that the leak is happening at your toilet, a faucet, or another plumbing fixture. Each of your faucets and toilets should have valves that open and close when you turn the water on and off. If you notice water dripping out of your faucet or into your shower or toilet, even though the water is turned off, it means you have a slowly leaking valve. 

How to Fix 

Unfortunately, the only way to fix a leaking valve on a toilet, faucet, or any plumbing fixture is to replace it. To do that, you should start by turning off the water and opening a nearby faucet to drain any excess water in the line. Next, remove the damaged valve from the water line and install a new one. 

Leak Around the Water Pump 

With any type of water pump problem, it’s always possible that the problem is originating from the pump itself. Your water pump will have a series of pipes and valves connected to or near it, including an inlet and outlet valve. Due to age, wear and tear, or cheap components, it’s possible that the seals around the pump are damaged. As a result, water will slowly leak, causing the water pump to pulsate on and off to restore pressure. 

How to Fix

If you have a leaky water pump, you probably won’t have to replace the pump depending on where the leak is stemming from. If it’s coming out of one of the attached pipes, you can try tightening the pipe or replacing the internal seals. If the leak is coming from the pump itself, however, there’s a good chance that you’ll have to replace the pump because an internal component has become damaged. 

Your Outside Shower is Running Constantly

If you have an outside shower on your RV, there’s a chance that you forgot to completely turn the water off. As a result, water might be leaking out of the open shower, causing the water pump to pulsate. 

How to Fix 

Obviously, you’ll have to turn off the shower water to get the problem to stop. 

When Should an RV Pump Cycle on and Off? 

The only time an RV water pump should cycle on and off is if you’re using water from your fresh water tank. If it’s pulsating any other time, it means you have a leak within the system that’s causing a loss of water. Your water pump will then turn on to maintain pressure. 

Frequently Asked Questions 

What causes a water pump to pulse? 

The use of water out of your freshwater tank will require the use of a water pump. It pulsates to maintain high water pressure, and will kick in and out if the pressure gets too low. 

Should an RV water pump pulse? 

Periodic pulsing of a water pump is perfectly normal while the system is in use. However, constant pulsing or pulsing when the system isn’t in use isn’t normal. 

Why does my water pump keep kicking on and off RV? 

If your water pump is kicking on and off in your RV but you aren’t using water out of the freshwater tank, you have a slow leak within your plumbing system.