How to Repair Your RV's Freshwater Tank

Repairing an RV water tank involves patching the crack or hole. If the crack or hole is too big to patch, the water tank must be replaced.

Difficulty: Moderate

Instructions

Things You'll Need:

• Small Disposable Brushes
• Rubber Gloves
• Rubber Gloves
• Epoxy Resins
• Fiberglass Patches

1. Drain the freshwater tank.

2. Remove the tank if the area that needs to be repaired is hard to reach.

3. Drill two small holes, one at either end of the crack you want to repair.

4. Sand the area around the crack to create a rough surface to which the patch can easily stick.

5. Cut a fiberglass patch bigger than the crack by one or two inches in all directions.

6. Mix the epoxy resin with its catalyst.

7. Apply the patch to the sanded, resin-covered area.

8. Lay the patch over the resin.

9. Cover the patch completely in the resin with a small brush.

10. Let the water tank sit for 24 hours before refilling it and checking for leaks.

Tips & Warnings

• Wear a mask to protect yourself from fumes.
• If the crack or hole is in a hard-to-reach area, you may have to remove the tank and then reinstall it when you're done.
• You have only 20 minutes in which to apply the resin. After that it starts to harden and becomes impossible to work with.

[jtmagoteaux]

on 5/20/2009 I only have the Double stick (Sure Seal made by Mule-Hide, same as Eternabond), will that work for my RV's freshwater tank or will i need to get the A-Seal too?My crack/pin hole is in a corner. thanks in advance

[HEDGEDOGS]

on 11/11/2007 Hi guys, this water tank fix-it idea is all well, and complicated....however I agree with # 2 in that something that 'attacks' the plastic works. In my case, the plastic tank was /is made from ABS.....and lo and behold, I fixed mine by removing the tank, and pretty much pouring/brushing one pint (or less) over the entire cracked area. it sealed, and made a thicker bottom where the crasks were........ALSO I painted all the joints/seams with the glue also....I assume the same could be done if the tank was PVC....painted with PVC glue instead....this was my quick-fix 'dummie' solution.....its lasted three years so far....Happy Trails

on 11/22/2005 Epoxy does not adhere well to Polyethylene (PE). It may work on a small crack or hole in a flat surface of a tank, but it will not work even on a half inch crack (small) near a bend or corner. Water tanks in RVs expand (sides bend out) when filled and then return to near original shape as they empty. An epoxy repair subjected to this motion will fail after only a few months use. Some epoxy claims assert adhesion to PE but check the specifications and you will find low values of lap shear for a PE bond. Also check the literature (Google search) for Polyethylene adhesion.

The best material I have found for PE tank repair is the Eternabond A-Seal material applied according to their on-line instructions. If there is a contour (dimple) at the repair site, such that it may be difficult to get the 4 mil aluminum of A-Seal to bend into all surfaces and get 100% initial surface contact, you may use some Eternabond double stick to create a smoother surface before applying the A-Seal. Warning: Plan carefully and get it right the first time, because Eternabond really sticks.

The PE tank manufacturers recommend removal and plastic welding (by an expert plastic welder) for repair, or best of all (per the tank manufacturers) replacement of the tank.