Why Does RV Water Pump Run But No Water?

Why Does RV Water Pump Run But No Water?

Published Date: June 15, 2021

Last Updated on June 22, 2023 by Camper Front

An RV water pump plays a very vital role in delivering water from the freshwater tank to the faucets and fixtures of an RV. But why does RV water pump run but no water?

While it tends to last long, several things can lead to its breakdown, which is one of the main reasons why the RV water pump runs but no water.

In this article, we will be exploring some of the more common reasons why RV water pump run even when there’s no water, and at the same time, prescribing a possible solution to the problem.

Why Does RV Water Pump Run But No Water?

Why Does RV Water Pump Run But No Water

Most times, issues with RV water pumps can be resolved easily if you should have a basic idea of the possible causes.

An owner of the RV water pump should try to diagnose its issues before making any repairs.

Below are the common reasons behind the phenomena above;

1. No Water in the Fresh Water Tank

First of all, the reason why RV water pump runs but no water could be due to the lack of water in the freshwater tank.

The question is; how can water flow from the water pump when the source of the water itself is very low or even empty.

If the above is the case, that means the water pump will pump air instead of water. Your water tank may show full reading at times, but you still have to crosscheck whether it’s full in reality or not.

Water tank level readers could be misleading sometimes. Just examine well, or even twice, before going any further in diagnosing and treating the issues.

2. Breakage of Pipelines

This condition might not be a regular occurrence, yet it’s possible. After getting no water and you checked the water tank level, it’s essential you check the water pipes to find out if there’s any kind of leak, and rather than moving to your faucet, the water spills on the road or floor.

Ensure every inch of the line is without leakage and that every connection, pipe joint or elbow are in order. Also, always snug up any connections to ensure they are secure and not close to come loose.

3. Air is in the Pump

After the above steps, the next reason that could have caused the RV water pump to run, but no water is the air that could be sucked in the pump.

You’ll have to appropriately observe if you are getting any water near the water pump through the line that connects between the freshwater tank and the suction of the water pump.

Attempt to open the pipe and see if water comes out from the opening. If you can see water coming out, it means the water is flowing from the water tank to the water pump, plus the fact that you may need to put some water in the water pump manually.

Whereby you don’t see any water coming out of the pipeline, then the pump has probably sucked in air.

To diagnose this, you will have to fill the pipe with water so that water comes out at the faucets. Then, start the pump again after filling in the water, and you should get the water within a minute or two.

4. Electrical Issue with Pump

Assuming you’ve checked everything and the above possible causes are intact. You still have to check for any kind of electrical issues.

Something must be wrong with the motor, and you will need a repair or replace it. Before you go into that, you have to identify the problem first, and that might take an electrical technician to do so.

If it has to do with the motor, then here are some of the most common motor issues that can lead to the malfunction of the water pump RV running but no water:

  • The pump is stuck, and you will have to examine the valve to tackle the problem
  • You need to replace the diaphragm on the pump as it seems to be torn or has been punctured.
  • The impeller is bad. For the hydraulic system in the pump to function properly, the impeller has to be in good condition. When it goes bad, you won’t get any water from your pump. So, you will need to replace the impeller
  • The motor has some debris inside. It happens, but a good sediment filter can handle the problem before it starts
  • In a rare case scenario, simply check for the sake. You will not miss a water leakage that leads to no water at the endpoint; if there are any pipe joints, check for those.


The above-highlighted factors can be summed up to be why RV water pump runs but no water. There might be other minor causes.

For instance, water pump ceases to work after winterizing, if water pump cycles on and off, if RV water pump makes too much sounds, if the water pump leaks so much water and so on.

However, if it happens that you noticed any of these possible causal factors, there’s a need to get an efficient mechanic or plumber to be precise to get them fixed.

Recommended Posts:

Scroll to Top