If you have a toilet that has been acting up and you are unsure whether to replace it, you can take a few steps to determine if the toilet is bad. There are several things that can go wrong with a toilet and the majority of those problems can be fixed by any do-it-yourself, enterprising homeowner. With a few different methods, you'll be able to tell if your toilet is bad.
Lift the top off the tank and lift the toilet lid. Flush the toilet and monitor the float or bulb, as well as the rubber stopper at the bottom of the tank. If the tank does not refill but continues to run, the rubber stopper is bad and needs replacement. If the float that shuts off the water does not stop water running into the tank, check the chain to ensure it is connected.
Place paper towels under the tank, around the edges and leave them sit for 48 hours. Pull the paper towels up and check for wet or soggy spots. If any are present, the wax ring under the toilet itself is corroded and water is leaking onto the floor.
Place a few squares of toilet paper in the bowl. Flush the toilet once again and watch the water recede. If the toilet paper squares do not flush and go down the soil pipe, you may have a water pressure problem and/or the toilet does not have sufficient G.P.F or gallons per flush. This means organic waste cannot be flushed from the bowl into the sewage system and the toilet needs replacing.
Check the toilet for cracks in the porcelain or ceramic. If large cracks are present, the toilet should be replaced as it may break, possibly flooding the bathroom.