All The Ways a Toilet Leaks and How To Fix Them Leaky toilets are a common household repair and are easy for an inexperienced person to fix. The trick is figuring out where the leak is coming from. A simple way to find out what's leaking is to drop a few drops of food coloring into the tank and wait an hour or two. Don't use the toilet and just let the food coloring sit in the toilet tank and do it's job. If after the wait you notice the colored water is in the bowl, then you have to replace the flapper. You would also make this repair if you noticed the toilet was running meaning filling up in between uses. You replace the flapper by turning off the water supply at the valve located at the bottom of the toilet. Flush out the water by holding the handle down. Dry the flapper and the valve seat and coat with petroleum jelly. Sometimes this will rejuvenate the rubber. If you have noticed black stains on your hands while handling the rubber flapper then replace the flapper. Disconnect the two rubber ears and slide the old flapper up the fill pipe and slide the new one down and reattach the rubber ears. Flappers are universal for the most part and will have an installation diagram on the package. Take the old one with you and you will have no trouble finding a replacement. Suppose the colored water is dripping down the back of the toilet where the tank and bowl connect. Then it could be a worn set of bolt washers or the seal between the bowl and tank is worn. You can purchase a kit that has a new bowl to tank seal and new bolt washers. Once again turn off the water. Loosen one bolt at a time and replace the washer. Be careful not to over tighten as you can crack the tank. If you need to replace the seal between the tank and the bowl you would remove both bolts and the tank comes off. Then you can replace the seal (which is a rubber gasket) and the bolt washers and screw the tank back onto the bowl. Sometimes the tank will crack, you can use a variety of glues or clear caulk to repair the crack. Empty the tank and allow the glue or caulk to cure before filling the tank again. Sometimes the chain will come off of the flapper or the handle arm. Just hook the chain back to the flapper or the handle arm and squeeze the hook a bit to hold it in place. And last but not least, if you flush the toilet and the colored water pools at the base of the toilet it usually means the toilet wax ring needs replacement. If the toilet moves or rocks you would also need to replace the wax ring. This doesn't happen often, but if it does you might want to have help, as a toilet is heavy. While the toilet is disconnected from the drain flange inspect the sub floor for any water damage. Disconnect the bolts holding the toilet base to the drain flange. Install a new wax ring, I like to use the one with the plastic collar and reconnect the toilet to the drain flange.