The Best Way to Diagnose a RV Water Pump That Runs But No Water Comes Out

Last Updated on July 8, 2021 by Douglas

Water is a basic human necessity. Even if you are roughing it by living in an RV, you would need an adequate supply of clean, fresh water. Most RVs come with some kind of a tank that can be used to store water. You would still need a RV water pump to access this water, though. The RV water pump would help you fill the tank. It would also bring water from the tank to your indoor plumbing. Sometimes the RV water pump runs but no water comes out, though. It might turn on but water would not be transported from the tank to your RV. A number of issues could cause something like this. The first thing you need to do is ascertain what the problem actually is. We will be discussing a few tips that can help you with that.

How to Figure Out What’s Wrong

Diagnosing the issue is an important first step for you to take. You can start off by listening to the RV water pump. Chances are that you already know what it’s supposed to sound like. If the sound is a bit off, that could be an indication of what the problem might be. Try to see if your RV water pump is working. If it’s working fine and the noise seems normal, the problem might be in your tank. We will be providing you a step by step process to diagnose your RV water pump issues.

Is it the fresh water tank?

If your RV water pump seems to be working fine, you should check out your tank. It might have sprung a leak. This is a common issue, especially on long journeys. Tanks are usually quite durable, but they can get damaged along the way. Check your tank if your RV water pump isn’t sending water to your pipes. If it’s empty, a leak might be the cause. Alternatively, the gauge might be broken. This would make it seem like the tank has water even if it’s empty. You need to keep both potential scenarios in mind.

Now, if the tank is in the problem then you’re in for a really tough time. You might have to spend a few days without fresh water. We recommend heading to an RV park to fix the issue. That way you can keep using the fresh water available there while you fix your tank. Part of diagnosing the issue is to fill the tank up and check for leaks. If there is a leak you should be able to spot it right away. Water would be gushing out of it, and you can use this to locate the leak and patch it up.

To fix the leak in your tank, you need to use filler material. This is specially made to fill up cracks in your tank. It’s perfectly safe to use since it doesn’t leach any substances into your water supply. You need to massage the filler before you apply it. This would activate it and make it more malleable. It would also make it more adhesive so that it sticks completely. Activating the filler material can help you to shape it specifically for the crack. It needs to fit perfectly otherwise it won’t properly plug the leak.

Has your RV water pump been primed?

In order to work properly, your RV water pump needs to be primed on a regular basis. Try to think about when you last primed your water pump. If it’s been a while, that would most likely be your issue right there. Priming your water pump basically involves clearing the water lines. Sometimes air can get trapped there. Since there’s nowhere for the air to go, it would end up blocking the water supply. Priming the water pump would remove the air. It maximizes water pressure which pushes the air out. A squeezable bulb is usually provided as a primer. You need to squeeze this bulb a few times and then turn the motor on to see if it’s been primed.

Priming is even more important if you travel in cold climates. Water in the pipes can often freeze under such conditions. Priming helps to break this ice down. High pressure water would shatter the ice and melt it. This needs to be done at least every other day during cold weather. If it’s happening during the summer, it’s more likely that it’s an air lock. Either way, priming the water pump should solve the issue. If it doesn’t then the problem is with your water tank or your water line.

Is there a leak in your water line?

If all else fails, your last resort would to check the water line. In fact, we would recommend that you do this first if your water lines are old. Older water lines are not made of durable material. They’re most often made of rubber which can leak rather easily. They also don’t have the reinforcements that prevent modern water lines from leaking. The leaks usually occur at the joints so that’s where you should start looking first. In certain cases cracks can also form along the water line.

These cracks are usually quite easy to find. Water would be gushing out of them so you can figure out where the problem is without too much trouble. Plugging up the leaks is similar to what you would do with the fresh water tank. Just use a filler after activating it. You would need a lot less filler with a water line. The cracks that form in the lines are generally a lot smaller. Hence, a small amount of adequately activated and placed filler should do the trick. Contact an expert if you have any issues.

Alternatively, you might not have a leak in your water tank at all. Instead there might be blockage. This happens quite often if you let your water tank run dry before refilling it. Debris can end up entering the water line when this happens. Air can enter the water line too. Either way, the blockage would prevent water from flowing freely. Another thing to note is that all water has some kind of sediment in it. This sediment will collect in your tank if it runs dry. Hence, the sediment can enter you water line too. This is the most common cause of water line blockages.

We would advise against trying to clear the blockage. Once it happens there’s no fixing it. Trying to push it out could cause even more damage. It could potentially push the sediment into your water pump. This would ruin it and force you to buy a new water pump. Just replace the water line if it’s blocked. It’s an affordable solution that can be done rather quickly. You can do it yourself too if you have a DIY mentality. It’s fairly easy to connect to pieces of pipe to each other after all. Once you replace the pipe, make sure that you never let your fresh water tank run dry again unless you’re cleaning it.

Try to bring your old water line along when you go out looking for a new one. This would ensure that you buy one that’s of the same size. Size truly matters in this situation. A new water line that is too long or too short would be useless for you. It also needs to have a similar thickness to your old line. If you have your old line to compare it to, the chances of such problems occurring would be greatly reduced.

The Less Obvious Problems

There are a lot of other problems that can occur as well. The ones we mentioned above are the more common ones. However, less common problems can be just as prevalent. Many of these problems have to do with the delicate internal parts of your water pump. These kinds of issues are harder to fix on your own. You might need to hire a plumber for the job. Trying to do it yourself could result in further damage being done. It’s always better to be safe than sorry when it comes to water pumps. As a last resort you can just replace your water pump in a few simple steps.

Start off by disconnecting the water pump from its power source. This is essential otherwise you can suffer an electric shock. It would be a pretty serious shock too, one that can do quite a bit of damage. Just turning the water pump off won’t be enough. Current would still be flowing into the water pump, it just won’t be joined via circuit. Turn the breaker off to be extra safe. In fact, we would go so far as to take the fuse out entirely. That way you can be sure that no electricity is coming to the water pump.

Most water pumps are installed on a mounting plate. They are either bolted or screwed down to this plate. If it’s the latter then this step is pretty easy. All you have to do is unscrew the water pump from the mounting plate. If it’s bolted down, though, the process would be a bit harder. Removing bolts often requires special equipment. Contact a professional if you don’t have this equipment. Alternatively you could rent a tool that’s meant for this sort of thing. Just make sure that you know how to use it less you break something and cause an even bigger issue.

Once the water pump is free from its mounting plate, you can disconnect it from all of its connections. This includes the electrical as well as water connections. You have already turned the power off, but physically disconnecting the water pump is important too. Otherwise you wouldn’t be able to take it to the hardware store! Some water might flow out of the lines once you disconnect the water pump from them. Don’t worry if this happens, it’s a normal part of the water pump removal process. There’s always some water in the lines and when the water pump is removed it will leak out of the lines.

Now that you have your water pump free from all of its connections, you can take it to a store where a specialist can take a look at it. There might be a chance that they can repair it. Otherwise they would have parts that they can use to replace the ones that have broken down. If not, they might have the same water pump except it’s brand new or only slightly used. You can replace your old pump and call it a day. Alternatively you could just buy a new pump. Just make sure that it has similar specifications to your old one.

All that’s left for you to do now is to connect the replacement pump back into all of the systems. Again, you need to absolutely sure that the electrical system is turned off. If you didn’t remove the fuse before, it’s even more essential that you do it right now. Reconnecting the pump is even more dangerous than disconnecting it. All the electrical supplies need to be turned off before you do so.

Bear in mind that if you buy a different pump, mounting it might be a little difficult. The holes in the mounting bracket might not be aligned. A drill should help you make new holes. They will be the right size and will also be positioned correctly. It’s a bit of extra work but it’s worth it. Especially if you’re getting a brand new pump that has more features.

Replacing a pump isn’t all that hard. However, we do recommend that you get a professional to do it. Too many things can go wrong for inexperienced people to safely give it a shot. An expert plumber would be able to get the job done in no time, and in a really safe way to boot.

Leave a Comment