Running Toilet vs. Leaking Flapper

What’s the difference?

This chart provides a side-by-side comparison of a running toilet and leaking flapper.
Additional information about toilets and these problems can be found on our Toilet School page.

RUNNING TOILET
(WIDE-OPEN FLAPPER)
LEAKING FLAPPER
 
CAUSE A toilet is caused when the flapper is prevented from completely closing properly onto the flush valve (it gets "hung-up"). This allows water to run continuously from the tank, into the bowl, and down the drain. This graphic explains how the flapper can get hung-up and why you may not know it. All flappers deteriorate over time. Leaks can also be caused by small pieces of grit or other debris in the tank getting between the flapper and the flush valve, causing the water in the tank to leak into the bowl. For more information about toilet leaks, click here.
COST A running toilet can waste 4.5 gallons per minute, (that's nearly 300 gallons per hour, or 6,480 gallons per day). That could increase your water bill nearly $60 per day. A leaking flapper can waste up to 200 gallons of water per day. That could increase your water bill more than $50 per month.
REPAIR
(ACTION NEEDED)
"Jiggle the Handle" (or turn off the water)

You just need to know when!
A leaking flapper should be replaced as soon as it is detected. When possible, use the manufacturer's recommended flapper, or a universal flapper if an exact replacement is not available. If you are not comfortable making this type of repair, a local plumber can make the repair for you.
HOW CAN THE LEAKALERTOR 6000 HELP? The LeakAlertor 6000 will let you know when the toilet is running, often before you leave the bathroom. The 6000 will continuously beep and flash the red lamp until the flapper is closed and the water begins to refill the tank. The 6000 will automatically return to normal operation once the tank begins to refill. Early detection of a leaking flapper is critical to reducing the amount of wasted water and reducing your water bill. Often times your first indication of a leaking flapper is a high water bill. The LeakAlertor 6000 will quickly detect a leaking flapper, as well as faulty fill valves, and alert you by giving a brief series of audible beeps and flashing the red lamp. (This graphic shows why dye tablets don't work well.)
  • I need more information about how toilets work… click here.
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  • I need more information about the LeakAlertor 6000 before I start saving money… click here.
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  • I’m ready to stop wasting water and decrease my water bill…
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Dye Tablets

5 Reasons why dye tablets are not accurate:

The LeakAlertor takes away the frustration of high water bills, and saves you money! Unlike dye tablets, the LeakAlertor is constantly at work checking for silent leaks, wide-open flappers, and faulty fill valves. It alerts you before you leave the bathroom with a “beep” and blinking LED during the flush cycle.

1) Errors are made in using dye tablets.
Often times, dye tablets are used incorrectly. Some people have mistakenly put the tablet in the toilet bowl rather than the toilet tank…test ruined! Some have put the tablet in the tank, and flushed the toilet immediately…test ruined! Some people drop the tablet in the tank, but then walk away and forget…again, test ruined!

2) Not all toilet leaks are caught by dye tablets.
Dye tablets can only detect one type of leak – a leaking flapper – and only if it’s leaking at the time of the test. However, stuck flush valves, wide-open flappers, phantom flushes, and running toilets are all common leaks not detected by dye tablets.

3) By the time you use a dye tablet your toilet may have already been leaking for weeks, or even months.
Often times, homeowners don’t realize a toilet is leaking because they think a leak should mean there is water on the floor. However, the most common leaks occur either at the flapper, or where the tank and bowl connect. These leaks occur inside the toilet, and are almost always invisible.

4) Intermittent leaks are often missed by dye tablets.
Just because your toilet isn’t leaking at the moment of testing doesn’t mean it wasn’t leaking an hour ago, or won’t be leaking an hour from now. Also, when a flapper first begins to leak, the amount may be too small for dye tablets to detect.

5) It’s not easy to get dye tablets.
Few hardware stores actually sell them, and it’s a hassle to contact your water utility for free tablets. You can buy them on-line, but you have to pay for shipping and wait for them to arrive. Meanwhile, your toilet continues to leak, and your water bill gets even higher!

7 Reasons why the flapper/flush-valve won't close:

1)  The flapper is “stuck” to the overflow pipe.
One observable symptom: it is not bobbing or floating in the water, regardless of the water height, and appears to be partially or fully upright.

2)  The chain is tangled.
A chain link can get stuck on the metal clip or loop over the top of the lever arm. Although an improper chain length causes many of these problems, “slapping” the flush handle can also cause the chain to hang up.

3)  A clogged drain/obstructed pipe produces back pressure through the flush valve seat.
The obstruction doesn’t allow the water level inside the tank to drop low enough for the flapper to seat properly. In this instance, the flapper appears to “hover” in the water above the flush valve seat. A clogged or obstructed drain pipe is the most common reason for toilets to overflow the bowl.

4)  A “universal” replacement flapper is purchased.
When a “universal” replacement flapper is purchased, it does not seat properly on the flush valve. Flappers should be purchased according to the type of flush valve used because universal flappers can leak and/or fail to seat up to 50% of the time.

5)  The flush handle/lever is old, defective, or “sticking” to the inside of the toilet tank.
Old or defective equipment can result in the flapper being held open.

6)  The flapper hinges are weakened and/or degraded.
This allows the flapper to slide to the side and not seat properly on the flush valve. (Note: the water flow from the fill valve can also push the flapper to one side if it is above 60 PSI.)

7)  A flapper’s buoyancy doesn’t become “negative” until the tank completely evacuates.
This does not allow the flapper to seat properly. Although there are several known causes (including toilet design), the most common is a clogged or obstructed drain pipe, which creates back pressure into the tank through the flush valve.


5 Common reasons why wide-open flappers often go undetected:

1)  No one is home to hear it running.
Often times, a person will use the bathroom before they leave their home (or business). In this case, a wide-open flapper would not be detected until the person returned home and realized the problem. This could be hours, or even the following day.

2)  The bathroom is not used frequently.
A wide-open flapper in secondary bathrooms (a finished basement or guest bathroom) can go undetected for days or weeks, wasting a tremendous amount of water and resulting in a high water bill.

3)  Hearing impaired/challenged people may fail to recognize a problem exists.
People with moderate to severe hearing loss may be unable to hear the running water. People afflicted with tinnitus may be unable to distinguish the sound of the running water from their tinnitus.

4)  The sound of the toilet tank refilling is a muted hum.
The initial flush of a toilet is loud, brief, and occurs while the user is still in the bathroom. However, the refilling of the toilet is quieter, prolonged, and typically finishes after the user has left the bathroom. Therefore, the user is unaware when the flapper remains wide-open.

5)  Background noise can easily mask the sound of a wide-open flapper or flush valve.
Examples include central air conditioners and HVAC systems (while the fan is operating); ceiling and window fans; music and/or TV; etc.