Toilets haven’t changed much in
the last 80 years. After a flush,
water still fills a tank, lifting a
float that shuts off the water when it
reaches a certain level. A lever still opens a flapper to
cause the flush, falling back into place when the water
level drops. So it’s no surprise (nor
any consolation) that we face the
same flush problems today that our
grandparents did. Sometimes the
flush is too wimpy, sometimes the
water keeps running, and sometimes
the bowl doesn’t refill.
Our ace plumbing consultant has a simple
four-step strategy to solve 95 percent of
these problems. You can complete the first three
steps in five minutes. That’ll solve most problems. The
fourth step is usually easy too, but not always. More on
this later. These steps work for most toilets but not for
Check the fill tube
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Overflow tube problem
Push the fill tube firmly onto the fill valve. Make
sure the fill tube sends water into the overflow
Remove the tank lid and find the fill tube.
It's a small flexible tube that runs from the
fill valve to the overflow tube. While the
tank refills, this tube squirts enough water
down the overflow tube to refill the bowl
after the completed flush. If this tube falls
off or the water stream misses the overflow
tube, the bowl won't fill and your next
flush will be wimpy (that is, won't develop
a strong siphon). Reattach the fill tube
and make sure it perches about 1 in. above
the rim of the overflow tube. Flush the toilet
and watch the water stream to make
sure it goes down the overflow tube.
Adjust the fill height
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Check the float
Adjust the float to set the water level. Pinch the clip and slide
the float up or down on the rod. Keep adjusting the float until the
water shuts off at the proper level.
The water level in the tank is controlled by an
adjustable float. A float that’s set too low produces a
weak flush; if it’s set too high, water spills into the
overflow tube and the fill valve won’t shut off. The
water will keep running. Look for the fill level mark on
the inside back of the tank and mark it on the overflow
tube so you can see it more easily. If you can’t find it,
measure down about 1 in. on the overflow tube and
make a mark. Then flush the toilet and see if the water
reaches and stops at that mark. If not, adjust the float
up or down. If you have an old toilet, you’ll have to
bend the brass rod that connects to the float ball to
make adjustments. But with newer toilets you usually
turn a screw or slide a clip along a rod. Flush the toilet
after each adjustment.
Also make sure that the water level is at least an inch
below the C-L (critical level) marked on the fill valve.
You can adjust the height of many valves to raise or
lower the C-L.
Occasionally the fill valve simply won’t shut off,
which means that it’s defective. If so, turn the water
supply off at the shutoff under the tank. Buy a replacement
valve (sold at hardware stores and home
centers). You don’t have to match the old one; many,
like the one shown, fit most toilets. It’s a 15-minute change-out.
Adjust the flush handle/flapper chain
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Flapper chain fix
Adjust the chain to leave a little slack with the flapper closed.
Then cut off the excess, leaving about an inch.
A chain that’s too short or tangled won’t allow the flapper
to close and water will continue to leak into the bowl.
This causes the fill valve to cycle on and off to refill the
tank. A chain that’s too long, or a flush rod that hits the
the tank lid, won’t open the flapper wide enough to stay
open for the full flush. You’ll find yourself having to hold
the lever to complete a good flush.
To avoid these problems, adjust the linkage in the
chain to leave only a slight bit of slack when closed. Cut
the chain at the rod to leave only about an inch extra to
reduce the potential for tangles. Then put the tank lid
back on and make sure the flush rod doesn’t strike the lid
when you press the lever. If it does, bend it down slightly
and readjust the chain.
Replace the flapper
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Change the flapper
Unsnap the old flapper and take it with you to the store to find
an exact replacement. In addition to the closest replacement,
pick up a “universal” type.
If you’ve completed the first three steps and your toilet
still runs, chances are you have a worn-out flapper. Turn
off the water, remove the old flapper and take it to the
store to find an exact replacement. (Hardware stores often
carry a wide variety.) Most flappers snap over ears on the
overflow tube. Others have
a ring that slips over the
Now here’s the catch.
You may not find an exact
match. The range of flapper
styles has mushroomed
over the last 15 years, and
you may find 15 to 20 flapper
options on the store
shelf. Some packages
include specific brand and model information (so note
yours before you leave home). Others have a “universal”
label. If you can’t find an exact replacement, try the closest
one and pick up a universal type as well. They’re
cheap, and the extra one just might save you a
second trip to the store! (Avoid the “adjustable” types
unless you’re replacing an adjustable one.)
Install the new flapper and make sure it opens and
closes freely. Then test it. If the water continues to run or
runs intermittently, you’re not getting a good seal. Try a
If you just can’t find a flapper that seals, consider
replacing the entire overflow tube/flapper.
On most toilets (two-piece),
this means removing
the tank. It’s not difficult
and you don’t need
special tools. It’ll take you about an hour, and you’ll
avoid that expensive plumber service call.