Problem: Mechanisms inside
toilet tank allow water to continue to run after toilet is
Background: To diagnose toilet problems, first lift off
the tank cover and watch the mechanisms in action when the
toilet is flushed. Next turn off the water supply to the
toilet and empty the tank of excess water. Specific
repairs will depend on the age and style of the mechanisms
inside the toilet. Both older and newer styles have a
mechanism to actuate an inlet valve that lets water into
the tank, and a mechanism attached to the trip lever that
allows water to flow out of the tank. The following tips
apply to the old-style components (see
Runs for trouble shooting toilets with new-style
mechanisms for flushing problems).
What to do: On the inlet side, the old-style ball
cock mechanism has a valve that opens and closes by a rod
that connects to a float ball. As the ball rises in the
tank it shuts off in coming water. On the outlet side,
older toilets often have a ball-type device which fits
into the seat at the bottom of the tank and holds water
until the toilet is flushed. This ball is known as a
stopper ball, tank ball, or flapper.
If the tank does not refill, first check to see that the
stopper ball is in good condition and is seated properly.
Adjust its chain or its guide arm, lift wires and the trip
lever so that the ball falls straight onto the seat.
Scrape away any corrosion from valve seat. If this fails,
the easiest way to correct the problem is to replace the
stopper ball and valve seat with a new-style rubber
If the stopper ball works, check the float ball and rod
assembly next. Make sure the float ball does not touch the
tank wall. The float ball may not rise high enough to shut
off the inlet valve; if so, check for a leaking float
ball, which will prevent it from rising high enough to
shut off the water. If the ball leaks, it is easily
replaced; just unscrew it from the end of the rod.
If the float ball is set too high, however, it may allow
water to flow over and into the overflow tube. In this
case, bend the float arm down until it is 1 inch below the
top of the tube; this will lower the water level. If the
float ball is set right, but water continues to flow, the
inlet valve in the ball cock assembly is most likely
defective. You can replace the valve washer, the entire
inlet valve, or the entire ball cock assembly.
Special advice: In some cases, a running toilet can
be caused by a refill tube end that is down too far in the
overflow tube, with its end below the water level. The
refill tube then becomes a siphon, draining water out of
the tank. To correct, reposition the tube so there is
space between the end and the water level. Also, when
troubleshooting with a running toilet, carefully examine
the base of the overflow tube. Corrosion can create holes
that allow water to drain continually from the tank.
Helpful hint: Low-cost
toilet tank repair kits are readily available for both
old- and new-style components. Depending on the problem,
instead of replacing major parts of an older system,
installing new-style components may be the best bet for
long- lasting, trouble-free performance.