How to Repair a Leaking Plastic Fresh Water Tank in a Travel Trailer

RV and travel trailers have numerous tanks on board for the supply of fresh water or the containment of waste water and fluids. When a fresh water supply tank begins to leak, you will find yourself filling it more often and wondering why. That musty or moldy smell also sends off warning signals that the plumbing needs to be looked into. Replacing a tank can be expensive. Since plastic tanks come in polyethylene (LDPE), or acrylonitrile butadiene styrene (ABS), manufacturers have devised products to repair them. Most trailer tanks have ABS construction and many kits can be obtained to repair these types of fresh water tanks.

Instructions

1

Drive the travel trailer to a source where you can loosen and open the fresh water tank drain valve safely and legally empty the tank. Transport the trailer to a convenient repair location, preferably on level, solid pavement. If necessary, disconnect the tow vehicle at the hitch and block the travel trailer wheels with chocks in the front and rear. Use a commercial trailer jack to lift the tank-side of the trailer and place two jacks stands under the frame.

2

Slide under the trailer and locate the leaking tank. Remove the fastening screws or bolts to the underbelly tank guard or shield with a socket or screwdriver. Drop the shield panel down. Pull any fiber insulation away from the tank and surrounding area by hand, to gain access to the tank mounting bolts. Locate the main fresh water inlet hose. Loosen the hose clamp for the fresh water one and pull it free.

3

Use a screwdriver to disconnect the vent line hose. If equipped with a floor panel access door, loosen and disconnect the inlet hose and vent line from that location. Use a socket, long extension and ratchet wrench to remove the tank mounting bolts. Have an assistant help support the tank while you remove the last bolts. Drop the tank to the ground and slide it out from underneath the trailer.

4

Locate the leak area on the tank. If the leak extends for any length, take a drill motor and small bit to drill holes at each end of the crack. Drill holes into the crack seam about 1/4-inch apart down its entire length -- this will allow more adhesion surface. Sand the crack with 200-grit coarse sandpaper, making cross-hatch motions to rough up the surface. Overlap the sanding about one inch on all sides of the crack. Clean the area thoroughly with plastic cleaner and a rag. Wipe dry with a rag.

5

Open a package of waterproof epoxy putty and follow the directions for preparing it. When you have the right consistency of putty, apply it to the crack surface, forcing the putty down into the drill holes with your fingers. Overlap the epoxy putty over the crack area by at least an inch or more. Let the epoxy dry and cure per the instructions, usually about six hours.

6

Install the tank into its mount with your assistant's help. Secure the mount bolts in their holes and tighten them all down with a socket, extension and ratchet wrench. Connect the freshwater inlet hose and tighten the clamp with a screwdriver. Connect the vent line and tighten the fastener with a screwdriver. Replace or reuse the insulation, tucking it back up into the undercarriage. Use spray adhesive to keep the insulation in place.

7

Mount the tank guard cover back into position under the frame, with your assistant's help. Replace the screws or bolts into their holes and tighten them with a screwdriver or socket. Raise the vehicle with the floor jack and remove the jack stands. Refill the freshwater tank and check for leaks.