Why Does Toilet Keep Running After Flushing

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Do you feel bothered when your toilet keeps running after flushing? Flushing the toilet should be a short, simple and straightforward process. However, some toilets may take longer than expected to complete. In fact, many toilets will keep running after flushing until you manually shut the water off.

The issue may occur because of some minor defects in the toilet system or due to a more serious problem with its underlying mechanism. Whatever the reason is, there are ways to deal with it. Read on and learn why your toilet keeps running after flushing and the easy fixes you can do to fix the problem.

Reasons Why Your Toilet Keeps Running After a Flush

Toilet Flapper Problems

One of the most common reasons a toilet keeps running is because the toilet flapper needs to be replaced. The flapper is a small rubber seal that covers the hole at the bottom of the tank. When you flush, the flapper lifts and allows water to flow from the tank and into the bowl. So, if you want to learn how to stop your toilet from running after flushing, then you need to be well conversant with how the flapper operates.

To check if a faulty flapper has caused the toilet to run intermittently, turn off the water supply and drain the toilet. Carefully remove the tank lid and peek inside. Check if the chain's length is too long or too short, which might be causing the flapper to lift prematurely. If so, adjust the length of the chain until the water stops running.

Build up of dirt around the flapper may also contribute to a slow draining toilet. Clean the toilet flapper before putting it back in place. If the flapper is cracked or broken, then you'll need to replace the entire toilet flapper.

Defective Fill Tube

The fill tube helps bring water into the overflow tube. If this is damaged or split, then it will cause water to continuously run into the overflow tube and out of the tank. Inspect the fill tube for any cracks or splits. If there are any, then you'll need to replace them with a new one or just invest in the best flushing toilets entirely.

Defective Fill Tube
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To resolve the overflow tube problem, remove the tank lid and find the fill tube. The fill tube runs from the fill valve to the overflow tube. While the tank refills, this tube squirts enough water down the toilet overflow tube to refill the toilet bowl after the completed flush.

If this tube falls off or the water stream misses the overflow tube, the bowl won't fill, and the water will continually run. Look for any cracks or splits in the fill tube and replace it with a new one if necessary.

Problem with the Flapper Chain

First, make sure the chain connects the flush lever to the flapper. If the chain is too long, it can get tangled and prevent the flapper from opening all the way and allowing enough water to enter the bowl for a proper flush. Shorten the chain by unhooking it from the flush lever arm and reattaching it to a different hole.

If you need to, cut off the excess flapper chain. The chain may also have a float attached to it, so adjust the float so that it sits on top of the water's surface. If that doesn't solve your problem, the flapper may need to be replaced.

Float May Be Out of Position

The water level inside the tank is controlled by an adjustable float. If the float is set too low, it creates a weak flush. If it's set too high, water will spill into the overflow tube and continually run. Look for a fill level mark on the inside back and set the float according to that. If it's set too high or low, adjust the float accordingly.

If you don't see a mark, measure approximately one inch down on the overflow tube and make a mark. After that, turn on the water and flush the toilet to see where the water level stops in comparison to the mark. If the water goes up, then the float for the pump is too high.

Adjust the float up or down accordingly. On an older toilet, you may need to bend the brass rod that's connected to float. For newer toilets, you'll only need to turn a screw or slide a clip along a rod. If the fill valve is defective, you'll need to buy a replacement from your local hardware store.

How to Fix a Running Toilet After Flushing

You Need to Lower the Float

Among the most common causes of a running toilet is overflow water leaking down into the bowl from the tank via the overflow tube. This happens when there is too much water in the tank in the tank. You can adjust the water level by adjusting the height of the float.

You Need to Lower the Float
Image credit: https://toiletology.com/

To lower the water in a toilet with a float arm, loosen or tighten the screws until the float arm lowers. To lower the water level in a toilet with a column float attached to the fill valve, loosen the screw or clip, push down the float and tighten everything back up again.

Also, check that the float ball is not touching the tank wall. You can easily fix the issue but make sure it's not getting stuck on the sidewall. This will ensure the level is lower than the overflow tube and stop a running toilet. Fill valves are cheap and easy to replace, so just replace the entire fill valve assembly if it isn't working.

Replace the Flush Valve

If your fill valve is working fine, the next step is to replace the flush valve. The flush valve is the large plastic or metal piece that sits atop the overflow tube in the center of the tank.

To replace the flush valve, turn off the water supply to the toilet using the isolated valve located in the water inlet line. After that, drain the toilet tank by flushing the toilet. Use a cloth or a towel to dry up any excess water around the valve seat.

Afterward, use a pair of pliers to remove the old flush valve from the tank by twisting it counterclockwise. You may need to tap on it with a hammer and a flat-head screwdriver if it's really stuck. Once removed, place your new flush valve in the same position as before and tighten it counterclockwise.

Lastly, turn the water supply back on and test your new flush valve by flushing the toilet again. If everything's working fine, give yourself a pat on the back! You're done with replacing this part of your toilet.

Adjust the Float Rod or Float Cup

If your toilet tank is refilling, but the water isn't stopping once it reaches the fill line, then you may need to adjust the float rod or float cup.

The float rod is a long, thin metal rod that's connected to the flush handle lever inside the tank. The float cup is a small cylinder that wraps around the fill valve and slides up or down with the water level.

You'll need to locate the screw that attaches the float rod or float cup to the fill valve. Use a screwdriver, a set of channel locks, or pliers to turn the screw clockwise or counterclockwise until the water level inside the tank stops just below the overflow tube.

If the water continues flowing, regardless of the position of the float rod or cup, then the issue will be the fill valve. But if the water stops flowing, but the volume of water inside the tank is not enough to properly flush the toilet, then the toilet's overflow tube is too short.

Replace the Flapper

If the water in the tank is not draining, then the issue is most likely with the flapper. The toilet flapper is one of the crucial devices that can help you stop the toilet running after flushing. The flapper is a rubber seal that sits over the drain at the bottom of the tank. When you flush the toilet, the flapper lifts and allows water to drain out of the tank and into the bowl.

Replace the Flapper
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To replace the flapper, remove the old flapper and replace it with a new one from the hardware store. Remove the old one by detaching the chain and taking the flapper off the pins on the side of the overflow tube. To attach the new one, connect the chain and attach the sides to the overflow tube.

Make sure you shut off the water supply to the toilet and then flush it before you begin this project. If replacing the flapper does not solve your issue, there may be another issue with the valve that needs to be repaired. Consult a professional plumber to help you diagnose and fix any other issues if necessary.

FAQs on Why Toilet Keep Running After Flushing

How long should the toilet run after flushing?

The toilet should run for about 20-30 seconds after flushing. If the toilet keeps running after flushing, then there may some problems that you may be able to diagnose yourself. If you suspect your toilet is getting old, leading to those problems, then consider purchasing a new one.

Why does my toilet run so long after flushing?

There are a few possible causes for your toilet to run longer than usual after flushing. One potential cause is that the water supply valve to the toilet might be old or damaged, preventing it from closing properly and causing the tank to refill continuously.

Final Thought on Why Toilet Keep Running After Flushing

When a toilet starts running and doesn't stop after a normal flush cycle, many people often wonder what they did wrong. If you're one of those people, don't worry! In most cases, the issue is an easy fix that you can take care of yourself without having to call a professional. If you're not comfortable fixing it yourself, don't hesitate to contact a professional plumber to help you out.



Ryan Copley

Ryan Copley

Having spent years participating in bathroom, kitchen, and home renovations, Ryan uses this experience to write informative blog posts on a wide variety of home renovation and kitchen topics.

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