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How to fix a toilet that won’t flush

The word “toilet” may not conjure an image of glamor, but imagine trying to live without one. And when something goes awry or it doesn’t flush, it can ruin the best of days. When that dreaded day comes — you flush and nothing happens — here are some tried-and-true ways to investigate and fix the issue yourself before calling a plumber.

How a toilet works

Use diagram found here if needed

To start, let’s get an understanding of the fundamentals and review the inner workings of a toilet. Every time you flush, it sets off a chain of events:

  1. When you press the handle to flush the toilet, you operate a lever inside the tank.
  2. The lever opens a valve called the flapper that allows the tank to empty into the toilet bowl through the flush valve opening.
  3. Water flows from the tank through holes in the rim so it washes the bowl as well as flushing the contents away by water flowing through a siphon jet.
  4. There’s enough water flowing down from the tank to flush the toilet around the S-bend (S-trap). This produces a siphon effect that sucks the bowl clean. It also ensures that some water remains at the bottom of the bowl, which improves hygiene.
  5. The contents of the toilet are flushed down the main drain.
  6. As the tank empties, the plastic float falls downward, tilting a lever.
  7. The tilting lever opens the ball valve (ball cock) at the base of the tank (or on one side of it), which works a bit like a faucet (tap). Pressurized water flows in, refilling the tank, and pushing the float back up again. When the float reaches the correct level, the ball valve switches off the water supply and the toilet is ready to flush again.

Now that you have an idea of the simple yet ingenious mechanics of a toilet, let’s read on for some common causes of a non-flushing toilet and what you can do about it.

Why a toilet doesn’t flush

Many times,a toilet won’t flush because of an issue between the three parts of the inside of the tank of the toilet: the handle, the flush chain and the flapper. Disconnection between these three can prevent a toilet from flushing properly. If the chain comes unhooked from the lift arm, the flapper won’t lift to allow water to drain from the tank, preventing the flush. If your toilet doesn’t flush and just fills with water, this might be the problem.

Steps to replace the flush chain

  1. Remove the lid from the tank. Place the lid out of the way on the floor.
  2. Turn off the water supply running to your toilet. Locate the knob behind your toilet and turn it clockwise until it’s tight. Flush the toilet manually to drain the water from the tank. When a toilet flushes, the flush lever pulls the chain to lift the flapper valve at the bottom of the tank, releasing the water. Lift the valve by hand, or with the broken chain if it’s still connected to the flapper, and allow the water to run out of the tank. This will give you better access to fix the chain.
  3. Identify the problems with the chain. If a chain is rusty and broken, it should be completely replaced. However, it could simply have a loose link that must be reattached. If the chain has come disconnected from the flush lever bar or the flapper valve, it will have to be reattached.
  4. Reattach the chain to the flush lever bar or the flapper valve if it has come loose. The chain connects to the flush lever bar with a small metal clip and attaches to the flapper valve with a small metal ring. Slip the chain back onto the clip or ring and use needle-nose pliers to tighten the link or ring. Fix broken links in the middle of the chain if both ends are still attached but the chain has snapped in the middle. Slip the two middle pieces back together and use needle-nose pliers to bend the links back together. Be sure to get them as straight as possible to keep them from pulling apart again. If the chain breaks again, replace the entire chain.
  5. Replace the rusted or broken chain with a new one. New chains can be purchased at a plumbing or hardware store. Use needle-nose pliers to remove the old chain from the tank, including the metal ring on the flapper valve and the small clip on the flush lever bar.
  6. Open the small metal ring that came with the new chain. Insert the metal ring into the hole at the top of the flapper valve. Put the last link of the chain onto the open ring and squeeze it closed with needle-nose pliers. Be sure it’s pushed together tightly so it doesn’t come loose.
  7. Thread the opposite end of the chain onto the metal clip and attach the clip to the hole on the end of the flush lever bar. If the chain is too long or has a lot of slack in it, try adjusting the clip, moving it down the chain to tighten the slack. Remove the extra portion of the chain by opening a link with the needle-nose pliers.
  8. Turn the water supply on by rotating the knob counterclockwise. Flush the toilet to make sure everything works. Adjust the tightness of the chain, if necessary. Replace the tank lid.

The toilet won’t flush but isn’t clogged

If you’re sure your toilet isn’t clogged and the flush chain is working properly, it’s time to look for some other reasons. Some possible explanations are:

  • The water level in the tank is too low.  The water level in a toilet’s tank should be approximately 1 inch below the top of the tank’s overflow tube. If the water in the tank is too low, check the water valve, as it may need to be adjusted to raise the water level.
  • The flapper is bent or warped. Remove the toilet tank lid and inspect the rubber flapper. The rubber flapper is designed to release water when the toilet is flushed and then close the water intake hole afterward so that the proper amount of water remains in the tank. If the rubber flapper on your toilet appears to have deteriorated or is too warped, bent or misshapen to seal the flush tube hole, you’ll need to replace it. Flappers are inexpensive items and can be found at any hardware or home improvement store.

Steps to replace a flapper

  1. Turn off the water.
  • Remove the old flapper. Disconnect the flapper chain from the flush handle lever. This lever is a horizontal bar that runs from the flush handle to a position just above the flapper. There is usually a small clip on the top end of the chain that hooks into one of the holes on the handle lever. Undo the clip and let the chain drop; you will replace this chain as you install the new flapper. 

    Slip the side ears of the flapper off the pegs extending from the sides of the flush valve tube. On flappers made of hard plastic, these ears will snap loose; on flappers made of soft rubber, the ears simply slide off the pegs.
  • Install the new flapper. Put the new flapper into place and hook each ear of the flapper onto one of the pegs on the sides of the flush valve. Connect the flapper chain onto the handle lever, adjusting the chain length as needed. When the handle lever is in the resting position, the chain should be relaxed, with a little bit of slack. If the chain is too tight, the flapper may not close completely. If the chain has too much slack, it can get caught under the flapper and prevent it from fully seating in the flush valve opening.
  • Turn on the water and test. Turn the water back on by turning the shut-off valve counterclockwise all the way. Test the new flapper and the chain length by flushing a couple of times and watching the flapper go up and down.

Time and cost of repairs

Keep in mind that if your toilet has bigger issues such as cracks in the tank, it’s wobbly, you’ve had to fix it often or it’s just plain old, you might need to replace the whole thing. Repairs can range from $15 to $150 in parts and $150 to $1,500 for a new toilet. Repairs by a plumber will take about an hour for smaller problems and one to three hours to install a new toilet.

Get a remote diagnosis from Anew

If your toilet still doesn’t flush after attempting these fixes, you might consider getting a professional opinion. Anew offers an easy, efficient and affordable repair service with remote diagnosis for only $20.

Get a remote diagnosis

Video chat with an expert to pinpoint your home’s issues, then get them repaired fast.

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Get a remote diagnosis

Video chat with an expert to pinpoint your home’s issues, then get them repaired fast.

Start My Repair

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