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RV Fresh Water Tank Repair (The Ultimate Guide)

Having an issue with your fresh water tank can be a little nerve wracking, especially if you are off the grid camping. Much of off the grid camping is about being prepared, and fresh water is pretty important. Discovering an issue with your fresh water tank is the first step to fixing it.

We’ll help you not only learn what to do to keep your fresh water tank from needing repair, but how to fix it in the event you have a problem. It’s all part of the RV experience!

Repairing a fresh water tank can be a matter of using sealants or having a professional look at the problem. Maintaining a fresh water tank is a matter of simple maintenance and ensuring your tank is clean and ready.

How to know when your RV fresh water tank needs repair

Are you losing fresh water? Do your sensors show a dip in water when you haven’t been using it at all? It’s even more obvious if you can see a crack in your fresh water tank and water coming out.

Those are the most obvious signs. You might have a slow leak or a leak at a height within the tank that only matters when you are full of water.

How to repair your fresh water tank

This is where things get interesting! A variety of fixes can temporarily and permanently stop RV fresh water tank leaks. Let’s go with easy and temporary first.

“Goop” or sealant

Before we start, keep in mind that whatever you seal your tank with is likely going to make contact with your drinking water. You’ll want to find a substance or sealant that has Food and Drug Adminstration approval, so you know it’s likely safe to ingest. 

One option instead is to temporarily seal your fresh water tank and use store bought or container stored water while you both wait for it to dry – and before you have a chance to get it professionally fixed.

Most epoxies and “goops” can seal a tank for a little while and can cover small cracks. Applying it is roughly like putting foam insulation into a crack in your house. 

Generally speaking, water proof tape won’t work. The RV fresh water tank has some exposure to the outdoors and the tape is meant to stop the flow of potentially moving water. The pressure is a bit different and likely to leak or fall off.

Repairing your RV fresh water tank with plastic strips

With a butane or propane torch, you can do a little do it yourself project and do what amounts to welding or melting a plastic strip to seal your tank.

First, find out what material your tank is made of. The answer is more than likely some kind of plastic like polyethylene or ABS plastic. 

You can then find and purchase plastic strips of the same material for welding or melting into place of the crack. Note that this normally works best for small cracks. If you have a large, highly visible crack over ½” wide that is gushing water, this might not be the best fit for you.

Welding or melting

First, if you aren’t comfortable working with a small torch or melting something to your tank, don’t do it. Be sure the plastic strip is made of the same material as the tank for the best effectiveness. Otherwise they might not bond properly.

You’ll need..

  • A butane or propane torch
  • A mask or respirator

You’ll want to place the plastic strip over the hole in the tank and keep it lodged in there somehow. One idea is to drill two small holes into the outside of the original hole and slide the ends of the strips in place.

You can then heat up the torch and melt the plastic strip in place over the hole until it’s sealed. 

The biggest difference between this and actual welding is that welding usually uses either a metal strip or the original metal to create a bond between heated metals.

Turn the profane torch off and set it aside somewhere so it can cool down.

The use of a plastic strip should at least last longer than a plug made of goop. 

Preventing problems with your RV fresh water tank

RV fresh water tanks can crack for a variety of reasons, including weather and pressure. Most RV tanks also have an overflow valve to relieve potential pressure.

One of the best methods of keeping your tank safe is to keep it free from corrosion. Keep the interior clean and don’t expose the inside to excessive oxygen.

You can also check the seals on a regular basis and see if you notice cracks. These can be replaced before they start causing issues.

Using an RV cover can also help your fresh water tank not experience sudden changes in temperature. Temperature swings can be hard on plastic and metal and lead to the weakening of the exterior tank, especially while under the pressure of holding water.

What should I do while waiting for repair?

Water is quite important to the human body. If you are off the grid camping and discover your fresh water tank has run dry due to a leak, the next option is to not use it.

Instead, opt for sealable containers temporarily. Find your nearest RV park or any place like a grocery store where you can buy or use water. Bring 5 gallon drums and whatever other sizes you need.


Having good drinking water is important when out and about on the road. It’s also nice to be able to keep clean of course! Repairing your fresh water tank can be a bit of a chore, but it’s relieving to be able to hold fresh water, even temporarily while exploring other options.

Just be sure the materials and plugs you are using are safe for consumption. Some of it could get into your fresh water tank.

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