How to Fix a Toilet That Flushes Twice

No matter your walk of life, hobbies, or what you do for a living, the toilet(s) are the most important seats in your home. They’re the kind of things that are often taken for granted, but if there’s a problem with any of them, suddenly, everyone notices and it can become a real problem. While some toilet issues may require emergency plumbing, others are simply an annoyance and/or a waste of water. Such is the case with toilets that flush twice. Why does it happen, and what can you do to fix it?

How does a toilet work?

Toilets are simple. When you flush it, the water in the tank is pushed into the toilet bowl, causing it to flush — which is why you can also flush a toilet by pouring a bucket of water into the bowl. Once flushed, the fill valve inside the tank pours additional water to refill it. Once the water reaches the fill line — which is measured by the fill valve — the water supply shuts off. Anything that pushes too much water into the toilet bowl will cause it to flush twice in a row.

Why does a toilet flush twice?

There are two main reasons why your toilet may be flushing twice.

1. The flapper stays up for too long

Not all toilets are created equal. Depending on the make, model, size, and shape of your toilet, it may need a specific type of flapper. If yours has a generic one or the incorrect size, it may stay up for too long every time you flush the toilet.

To know which kind of flapper your toilet needs, look at the flush drain at the bottom of the toilet’s tank. If it’s the size of a tennis ball, you’ll need a two-inch flapper. If it’s the size of a softball, you’ll need a three-inch flapper. The wrong-size flapper can also cause a toilet to run endlessly. So when buying a replacement, always make sure to know the size your toilet needs.

How to fix it: Remove the lid of the toilet tank and flush the toilet. Pay close attention to the flapper. Does it close immediately after flushing, or does it either stay open or slowly make its way back down? Either scenario means your toilet needs a heavier flapper. Take note of the make and model of your toilet. Go to a home improvement store to get the flapper you need.

When you return home, shut off the water supply to the toilet. Flush it to empty the tank. Remove the old flapper and replace it with the new one. When reconnecting the chain, make sure it’s neither too tight or too loose.

Related blog: How to Replace a Toilet Flapper

2. The fill valve is not adjusted properly

The fill valve controls the amount of water inside the toilet tank. If the fill valve is not adjusted properly, too much water will escape the tank and seep into the bowl, forcing the toilet to flush again.

How to fix it: Remove the screw on top of the fill valve with a screwdriver to lower the float arm. Once adjusted, replace the screw and flush the toilet to test it. If your toilet’s fill valve doesn’t have a screw on the top, you have an outdated valve – which is probably why it’s faulty. You can purchase a new fill valve at any hardware store. The package will include the fill valve, a refill tube, a lock nut, and a gasket.

To replace it, you’ll need pliers and an adjustable wrench. Shut off the water supply valve, remove the tank lid, and flush the toilet. Remove the existing fill valve by reaching into its base and pulling up the lock ring. Proceed to slide the fill valve off its base. Slide the new valve into the base in the tank. Reach into the base and snap the lock nut/ring into place. Insert the refill tube into the overfill tube.

Related blog: How to Replace a Toilet Fill Valve

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