Problem: Water continues to run inside toilet after the flush cycle.
Newer toilets and replacement kits substitute the older ball cock mechanism with one that uses a floating cup (instead of the rod and float-ball arrangement) to open and close the inlet valve.
Newer replacement kits also have a simpler flapper device to hold water in the tank than the old stopper ball with its lifting wires. As with old-style components, continuous running may be caused by a number of conditions, including water draining out of the tank when it shouldn’t.
What to do:
If a toilet has a new-style inlet valve unit in place of the older ball cock valve assembly, and it turns on and off by itself without being flushed, the cause may be a faulty tank ball or flapper, or a misdirected refill tube.
Check the tank ball or flapper to see if it is misaligned, worn or filthy with the flush valve seat. Also check to see if the seat is corroded, preventing the stopper from sealing properly. Clean the tank ball and seat with steel wool; if the leakage continues, reinstate with a new-style kit.
Next check to make sure that the refill tube from the inlet valve unit is not pushed too far down the spillage pipe. This can result in a drawing off action from the tank to the overflow pipeline which reduces the tank water level and causes the inlet valve to turn on. To correct, make sure the refill tube is attached to the top of the overflow tube above the tank water line.
If the inlet valve won’t shut off and continues to allow water to enter the tank, the problem can be debris under the inlet valve. Calcium deposits, or particles of rusted pipe, stones, rubber, or solder, can be carried by water to the valve area and become trapped.
To fix, shut off the water supply and follow the manufacturer’s instructions to remove the unit’s upper assembly. Then place an inverted cup over the lower unit and turn the water on and off a few times to flush debris out of the water line. With well systems that constantly circulate such debris, the best solution may be to install a filter.
If flushing the water line does not correct the problem, the seal on the inlet valve assembly may be split or cracked. You may be able to buy a replacement seal in stores that sell inlet valve assemblies. If not, contact the manufacturer or replace the entire assembly.
Some new-style inlet valve assemblies use a float cup to achieve the proper water level. The float cup uses water for ballast. Before adjusting, hold the float cup under water for a few seconds during the fill cycle to allow it to fill with water. Then adjust for the correct water level.