State University Extension
Home Maintenance And Repair - 01500166
Flush Tank Problems
Several problems can develop:
-Tank continues to run after tank fills
-Tank doesn't fill but water continues to run
-Tank partly empties
-Water leaks on the floor
-Nothing happens when you push the flush handle
-No water pressure available
1. Procedure if water continues to run after tank refills. (Vis. 1)
The problem is the water inlet valve is
not seating tight enough to shut the water off.
isolate the problem, remove the tank lid. Grab the float and lift.:
the water stops running the problem is in the float mechanism. If the
float is over half submerged look for a leak in the float. Check the
float and repair or replace. If the float is okay, adjust the float
downward. This can be done by: (a) adjustment screw on top of the ball
cock. (b) bending the rod supporting the float. The recommended water
level is often marked on the tank wall. If not, the water level should
be about 1" below the overflow pipe.(Vis. 1a)
you cannot stop the water flow by raising the float, the problem is
probably the inlet valve in the ball cock.
off the water to the tank by turning the valve below the tank or by
closing the valve in the main supply to the house. Remove the float
assembly by unscrewing two thumb screws. This will allow you to lift
the valve. In other ball cocks, unscrew the two thumb screws on either
side of the top assembly and lift it off. The valve assembly should
drop out. (Vis. 1b)
Replace the rubber washer in the bottom of the valve. If you do not
have a new washer turn the old one over as a temporary repair until you
can get a new replacement. Check the size before you reassemble. (Vis.
check the gasket or "O" ring toward the top of the valve. This should
be pliable so it will prevent the incoming water from squirting out
around the top of the valve. (Vis. 1d)
the valve and turn on the water.
2. Procedure if tank doesn't fill but water continues to run.
a. The problem is most likely that the
tank ball is not seating. Check to see if the linkage is binding or
hooked so it does not let the ball go completely down. Or the tank ball
might be so old it is wrinkled or cracked so water is running through
the tank ball. (Vis. 2)
solution is to buy a new rubber tank ball and/or a new linkage and
replace the old worn parts. You might consider replacing the entire
tank ball and linkage with a flapper valve. (Vis. 2b)
to use, water, and salt deposits, the flush handle might bind and not
let the tank ball reseat. Put a few drops of penetrating oil on the
handle just inside the tank and wiggle it back and forth. If the handle
is rusted so bad it cannot be loosened with the oil a new one will have
to be installed. To do this remove the nut inside the tank. This is
usually a left hand thread so to loosen you would turn clockwise. (Vis.
3. Procedure if water leaks on the floor. Water on the floor underneath
the toilet tank may be caused by one of the following:
a. Condensation on the outside of the tank
due to cold temperature of the water. This will almost always happen in
the summer, when the temperature and humidity are high. In the winter
it will not occur.
solution to the problem might be:
or sew a jacket for the outside of the tank which acts as an insulator.
Wash it frequently, to keep it clean.
of insulation material can be purchased to install on the inside of the
tank. These require considerable effort because the inside of the tank
must be dry and clean. The insulation must be installed so water cannot
seep between the insulation and the tank wall.
valve can be purchased which will proportion a fixed amount of hot and
cold water into the tank to make the water temperature high enough to
prevent condensation. The requires an alteration to the plumbing system
but is very effective. It will "waste" heated water.
- Buy a
tray which hangs under the tank, usually hooked to the top of the tank
with thin metal strips. Put sponges on the tray to soak up the water
dripping on to the tray.
leak in the water pipe to the tank. The water leaking from this source
will usually be in a puddle under the end of the tank where the water
pipe connects to the tank. Look under the tank and see if there is an
accumulation of salts around the pipe.
times a one quarter or one half turn on the nut next to bottom of the
tank or on either side of the shut-off valve (if there is one) will
stop the leak. (Vis. 3)
tightening the nut does not stop the leak it is probably the gasket at
the bottom of the "ball cock" where it goes through the tank.
this, disconnect the water pipe to the ball cock after dipping out
water. Loosen the big retainer nut under the tank and remove the "ball
cock" assemble. Replace the rubber gasket and reassemble the unit.
refill tube may be misdirected so it directs the water against the top
or side of the overflow pipe causing it to splash against the top of
the tank and running down the outside of the tank. If this happens when
you take the top off, readjust to direct water down the filler
packing or "O" ring on the inlet valve may be worn so when the toilet
is flushed and the valve is opened the water squirts out the top of the
"ball cock" against the tank top and runs down the outside of the tank.
The procedure for replacing this packing
is the same as for replacing the valve seat.
4. Procedure when tank partly empties. Sometimes when you pull the
flush lever the tank partly empties or the handle must be held down to
completely flush the toilet.
a. Check to see if the mechanism or chain
connected to the rubber tank ball is free and not kinked. If so, adjust
the length so the rubber tank ball is lifted higher when the flush
valve is released. This will allow more time for water to enter the
5. Procedure if nothing happens when flush handle is pushed. After many
years of use the linkage between the handle and the float wears out and
a. Remove the tank top and find out which
part is worn out. Replace it with a new part which can be purchased at
most stores selling plumbing supplies.
repairs can be made with a wire or cord if a new part cannot be
obtained for several days.
6. Procedure if there is no water pressure. When the water pressure is
gone the flush tank will not fill for the next flush. All that is
needed to flush the tank is a big rush of water in the stool so a pail
of water dumped into the stool will flush it. Then part of a pail of
water must be poured in for the next use.
Installing A Ball Cock
When installing a new ball cock, make sure it is an anti-syphon ball
cock to meet code requirements. This type of ball cock guards against
contamination of the fresh water supply.
New types of ball cocks:
1. Diaphragm ball cock (Vis. 4)
a. Install the ball cock in the same way
as conventional models. Follow the directions that come with your ball
b. If the water supply contains a high level of minerals, the
moving-parts of a diaphragm ball cock should be occasionally cleaned.
c. After several years of use, the diaphragm and valve may need to be
replaced. These parts are available as a kit from a plumbing-supply
2. Float-cup ball cock (Vis. 5)
a. To install the float-cup ball cock just
follow the procedure for a conventional ball cock. The float ball and
rod arm are eliminated on this ball cock.
b. An adjustable sliding clip permits setting of tank water level.
This article was written by Anne Field, Extension Specialist, Emeritus,
with references from Michigan Extension bulletin E-812
Flush Tank Problems.
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June 30, 1914, in cooperation with the U.S. Department of Agriculture.
Thomas G. Coon, Director, MSU Extension, East Lansing,MI 48824. This
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products or trade names does not imply endorsement by MSU Extension or
bias against those not mentioned.
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