Symptoms
- Water pump makes no sound when the faucet is turned on
- Pump runs but no water comes out
- Pump cycles on and off rapidly even with faucets closed
Likely causes
- CommonFresh water tank empty or very lowPumps need water to prime and won't function correctly, or at all, if the tank is empty.
- CommonBlown fuse or tripped breaker for the pump circuitRV 12V systems commonly have a dedicated fuse for the water pump that can blow.
- CommonWater pump switch left off, or a low-battery cutoff engagedSome RVs have a separate pump switch at a panel that's easy to overlook.
- PossibleAir trapped in the lines or a small leak causing rapid cyclingAir pockets or a pinhole leak can cause the pump to cycle on and off frequently.
What to do
- Check the fresh water tank level first, since a pump won't work correctly if the tank is empty or nearly so.
- Confirm the water pump switch (often on a monitor panel) is turned on.
- Check the RV's 12V fuse panel for a blown fuse related to the water pump and replace it with the same amperage if blown.
- Check the house battery charge level, since a very low battery can prevent the pump from running properly or at all.
- If the pump runs constantly or cycles rapidly, check all faucets are fully closed and inspect visible water lines and connections for leaks.
- Bleed air from the lines by running each faucet for a minute if the system was recently filled or winterized, since trapped air can cause sputtering or cycling.
Tools and parts
- Multimeter (optional)
Replacement fuse for the water pump circuitSearch: “RV water pump fuse”
When to call a pro
If the pump has power and water but still won't prime or run correctly, or you find a leak in the plumbing, have an RV technician inspect it.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.