Your RV water pump is a vital appliance for your RV’s fresh water delivery system when you aren’t at a campground. When disconnected from city water, it pressurizes your RV’s plumbing lines to deliver water to the sinks, toilet, and shower. Most RVers use their water pump between campsites. Boondockers and off-grid campers use it much more frequently. If it fails, it eliminates your ability to wash dishes, get clean drinking water, or take a shower. And you’ll likely find yourself asking: why is my RV water pump not working?
So, what are the potential causes of water pump failure? And how can you troubleshoot them?
Fortunately, that’s what we’re here to detail. Let’s get started.
How Does an RV Water Pump Work?
When turned on, your RV water pump creates pressure in your plumbing lines to move water from your potable water-holding tank to your RV’s faucets, fixtures, and water heater. There are different water pump sizes depending on your RV’s size. The average output for most RV water pumps ranges from 3.5 to 5 gallons per minute (GPM).
To use the water pump in an RV, your freshwater holding tank must have water, and any bypass or siphoning valves must be in the correct position. Check your owner’s manual for diagrams and instructions on those valves and their proper positioning.
With those prerequisites met, here’s the basic operation of an RV water pump:
- Turn the water pump on at your RV’s control panel. You should hear the pump run to pressurize the system.
- Open the faucet or fixture you want to use. The pump should run to maintain a consistent water pressure.
- Close the faucet or fixture. When your demand is complete, the pump may run for several seconds to build pressure back into the system.
Remember to turn your water pump off between uses. A working water pump only takes a few seconds to build system pressure. Your water pump should also be turned off while driving, when connected to city water, overnight, and when leaving your RV unattended.
Learn more about how RV water systems work.
Why Is My RV Water Pump Not Working?
If your RV water pump is not working, follow the questions below to troubleshoot the easiest causes first. You can also download this RV water pump troubleshooting decision tree for reference.
Is the water pump on?
If you open the faucets and aren’t getting any running water, the first thing to check is whether you’ve turned on the pump. Some residual pressure may cause water to exit a fixture at first, but that pressure will drop, and water flow will decrease unless the pump is running.
Check the control switch for the pump before proceeding to other troubleshooting measures.
If the water pump switch is on, is it lit up?
The control switch for the water pump may or may not be backlit with a red light that signals the switch is turned on. If yours does have this red light, it should illuminate when the switch is on. If yours doesn’t, listen for the sound of the pump running to pressurize the system. This is your signal that power is running to your pump.
If the switch is not lit, check the fuse panel. Is the red fault light next to the pump fuse lit?
If the control switch doesn’t light up or you don’t hear the pump run when turning the switch on, start by checking your DC distribution panel. Locate the fuse associated with your water pump.
Technician Tip: If your fuse panel isn’t labeled, we highly recommend scheduling an electrical system diagnostic and requesting that the RV technician inspect and label the panel properly.
If the fault light next to the pump fuse is lit, remove the fuse and visually inspect it. If the fuse is blown, you’ll need to replace it with a fuse of the same size and type. However, if the new fuse blows soon after this replacement, something is causing the fuse to blow, and a certified technician should inspect your electrical system.
Is there enough 12-volt power in the camper to actually make the pump run?
If you’re dry camping, you may have run the battery down too far and, consequently, don’t have enough power to activate the pump. Typically, a battery registering 10.5 DC volts or less is considered dead. The water pump’s motor will continue to try to turn at lower voltages, but this creates added stress that can lead to the motor overheating and premature water pump failure.
There are several ways to recharge your battery. The two simplest methods are to connect your RV to a portable generator or plug into shore power. If you have a towable RV, you can also recharge the battery by plugging the 7-pin electrical connector into your tow vehicle while the engine is running.
Can water get from your fresh water tank to the pump?
Some water pumps are equipped with a siphoning valve and hose for RV antifreeze. If this is the first trip of the camping season, it’s possible that the siphoning valve is still bypassing the pump. In most RVs, this pump is located on the water line running from the freshwater holding tank to the water pump. Ensure it is in the proper position to allow water to flow from the tank to the pump.
Are your low-point drains closed?
Most RVs are equipped with multiple low-point drains. Typically, you’ll have a drain for your potable water tank, one for your cold water plumbing line, and another for your hot water line. If these drains aren’t closed, your water pump won’t be able to build pressure to deliver water to your fixtures. In fact, the pressure it creates will cause water to run more quickly out of the open hot or cold low point drain, wasting water and potentially creating a mess under your RV.
Is the pump failing to deliver adequate water pressure?
If the pump is running, but you’re not getting good water pressure, double-check that you have water in the tank and inspect the connections on the pump’s inlet and outlet. Loose connections can lead to inadequate water pressure.
Additionally, you should check that water is actually getting to the pump. However, doing so will require care to avoid a mess. Your goal is to disconnect the line between your tank and the pump. If water exits that line when disconnected, you’re getting water to the pump. But you’ll want to plan for a quick, effective method to trap and/or dry that water before it damages any interior materials that aren’t water-resistant.
If water doesn’t exit the line when disconnected, inspect the line for damage or clogs. Ensure you fill the line with water before connecting it to the pump.
If these methods don’t fix your inadequate water pressure issue, you could be dealing with a failing water pump. However, we recommend consulting an RV technician for assistance before exploring a replacement RV water pump.
Is the pump running continuously?
Your RV water pump should turn off when all fixtures and faucets are closed. It shouldn’t turn back on again until demand causes a drop in system pressure. If it continues to run, it could be a sign that you have a leak somewhere. The pump will continue to run if it can’t maintain the prescribed pressure.
Where To Find an RV Water Pump Replacement
When properly maintained, your RV’s water pump can last a decade or more. However, improper care can lead to the need for a replacement. The most common causes of water pump negligence include:
- Improper cold weather storage
- Corrosion or mineral buildup (potentially due to the failure to use a water filter)
- Leaving the pump running without water in the holding tank
If you’re certain that your RV water pump is not working and it’s time for a replacement, we have a great selection of RV water pumps at different output ratings.
Replacing an RV Water Pump
Tools Required
If you decide to replace your water pump and you’ve acquired a compatible pump, start by gathering the right tools for the job, including:
- A drill or screwdriver
- Wire cutters
- Wire stripper/crimper
- Spade connectors
- Bowl or bucket (for water catchment)
- Towels or sponges (for clean up)
Steps for an RV Water Pump Replacement
With your new water pump and the right tools ready, here are the steps to replacing your RV’s water pump:
- Disconnect from city water and turn off the power to the pump. Some also remove the pump’s fuse as an added precaution. Alternatively, you can disconnect your RV from shore power and flip the battery disconnect switch to remove the power supply to all RV appliances.
- Close the valve on the suction line between the tank and the pump – or drain the tank altogether to experience less spillage during the replacement of the pump.
- Open a faucet to bleed pressure from the lines. This is also a good time to disconnect your pump from a latching controller if your RV is equipped with one. This controller allows a pump to operate from multiple control switches.
- Remove the inlet and outlet lines from the pump and the screws securing it in place.
- Remove and clean the inlet filter before reinstalling it on the new pump.
- Strip the wires and crimp spade connectors in place for the latching controller (if applicable). You can use butt connectors to make wiring connections if your RV isn’t equipped with a latching controller.
- Mount the new water pump with existing screw holes and connect inlet and outlet water lines.
- Connect the pump wires to the latching controller.
- Replace the water pump fuse and turn on the control switch for the pump.
- Open water faucets to check for proper operation and inspect water connections for leaks
Technician Tip: When turning on the new pump, you may need to bleed air from plumbing lines. Allow the pump to run to remove air until you get a steady water stream from the faucet.
Troubleshooting is a part of the RV lifestyle. Search our complete troubleshooting archives for help diagnosing issues so you can get back to enjoying your camping trip.
Do you have any questions about troubleshooting or replacing the water pump in your RV? Let us know in the comments below.
