Solved! What to Do About a Leaking Toilet Tank

Faced with a leaky toilet? To dry things up, you'll first need to track that leak down to its source. Pinpoint the culprit with these quick troubleshooting tips.

Toilet Tank Leaking - What to Do


Q: Help! My toilet is leaking all over the bathroom floor, and I haven’t yet located the source. How can I find and fix the cause of the leak before any real damage occurs?

A. Some of the biggest problems homeowners encounter start small and then suddenly spiral out of control—and this is precisely the path that leaks tend to follow. A hairline crack or chip that allows even a few drops to seep out can become a much bigger (and costlier) problem if not dealt with right away. The following troubleshooting tips run through the most common causes of leaky toilets. These should help you both pinpoint and fix the problem, so you can stop the water from seeping from your toilet—and prevent cash from seeping from your wallet.

Toilet Tank Leaking


The most common type of leak occurs at the bottom of the toilet tank and is usually associated with the emptying and refilling of the tank after flushing. The culprit? Oftentimes a worn-away spud washer (the big rubber washer, sometimes called a tank-to-bowl gasket, that seals the opening at the bottom of the toilet tank) or crumbling rubber washers at the bolts on the underside of the tank. Any of these washers can deteriorate over time as a result of exposure to hard water or minerals, but all are relatively easy to replace. Begin by turning off the water supply at the wall and then emptying the toilet tank with a flush. Disconnect the water supply from the tank, and then use an adjustable wrench to remove the bolts, nuts, and their washers from the underside of the tank. Lift up the tank (get a friend to help!), turn it on its side, and remove the spud washer from the bottom.

Another potentially troublesome mechanism is the ball cock, which is responsible for filling the toilet tank. It, as well as its fill valve, can fail over time. As it’s secured to the tank with just a nut and washers, replacing the ball cock mechanism is easy and usually costs about $10. But before you start emptying the tank to make a switch, first check for any loose connections between the water supply line and the existing ball cock. You may be able to fix the problem with a simple tightening—which is much simpler than making a trip to the store.

If a toilet leak seems to be coming from the bottom of the toilet itself, you might look for a failed wax ring affecting the seal. This is a much bigger issue than replacing washers and checking water lines, if only because it involves total removal of the toilet itself to inspect foundation items. First, confirm that the wax ring is to blame: Make sure the water is turned off and the tank is drained properly. Then, remove the cover caps and unscrew the toilet from the floor, carefully moving it (again, you might want to grab a friend) to expose the flange area for inspection. If the wax ring has failed, you can purchase a new one to replace it; the same goes for any obviously corroded bolts. Once the new parts are in place, caulk the base of the toilet to serve as one last DIY safeguard against leaks for (we hope) years to come.

  • Favorites Flipboard Facebook Twitter Pinterest Email AddThis