Toilet Flushes Twice: Causes & Quick Fixes

It can be frustrating when you flush your toilet only to have it seem to flush a second time right after. Rather than a ghost in the pipes, this phenomenon usually has a mechanical cause. A toilet that flushes twice is most often the result of some issue within the tank that is causing it to cycle improperly.

The main cause of a double flush is too much water in the toilet tank, which causes an overflow during a flush. The flapper staying open for too long is another cause. In this position, it flushes too much water and needs to be adjusted accordingly. The flapper should close as soon as you let go of the flush button/handle. You can adjust it by increasing the length of the flapper chain/lever.

The tank contains a number of components that allow it to fill with water after a flush and then refill the bowl again when you pull the handle. Issues with the flapper valve, fill valve, float, or other tank parts can lead to extra flushes. Problems like a worn flapper, mineral buildup, incorrect water levels, and debris in the valves are common culprits. Even modern dual flush mechanisms can sometimes accidentally trigger two flushes.

Figuring out why your toilet is flushing twice involves inspecting the various tank components to isolate the problem. With some adjustments and replacement parts, you can usually get it working properly again with just a single flush. Identifying the root cause is key to resolving the annoying double-flushing behavior. 

A toilet in a bathroom

Why does my toilet flush twice?

Before explaining the causes behind your toilet flushing twice, keep in mind that this is different from a ghost flush. A phantom or ghost flush occurs when the toilet flushes itself when no one is using it. A toilet flushing twice occurs when you flush the toilet, and before the first flush ends or right after it ends, it flushes itself again.

There are a few potential reasons why your toilet might be flushing twice:

Flapper valve malfunctionReplace worn-out parts
Too much water in the tankAdjust the water level
Dual flush mechanismPress one button at a time
Mineral buildupClean the toilet tank
Old/faulty partsReplace worn out parts
Toilet tank leaks Fix toilet tank leaks

1. Flapper valve malfunction

The flapper valve at the bottom of the toilet tank may not be sealing properly after the first flush, allowing water to leak through and trigger a second flush. A worn-out or misaligned flapper can cause this.

2. Dual flush mechanism

Many modern toilets have a dual flush feature, which allows you to choose between a full flush (for solids) or a half flush (for liquids). If you’re not fully pushing the flush handle, it may trigger a second, light flush. This goes against the purpose of dual flush toilets, which is being more efficient.

3. Tank water level too high

If the water level in the tank is set too high, water can get siphoned over into the bowl while the tank is still refilling, making it seem like a double flush. Adjusting the float should fix this.

4. Mineral buildup

Mineral deposits from hard water can prevent the tank valves and flappers from sealing correctly. This can trigger a double flush of the toilet.

This issue is common in areas with salty or hard water. I used well water on my trip to Mexico and experienced this a lot.

5. Old/faulty parts

Outdated or failing tank components like the flapper, fill valve, or flush lever can result in a toilet that seems to flush twice with one lever push. Replacing them may be required.

If you’re living in an old house or the house has had many occupants over the years, you may face this issue. Luckily, replacing a toilet altogether isn’t costly.

If the issue is inconsistent, it’s likely a mechanical problem. Start by inspecting the tank components and making any adjustments needed. If the problem persists, replacement parts may be in order. If you’re not skilled enough, call for an expert to fix the issue you face.

How do I fix a toilet flushing twice?

Before you imagine it’s a ghost, and before your water bill starts running unnecessarily high, here are some steps to try to fix a toilet that keeps flushing twice:

1. Adjust the flapper chain

Ensure the chain that connects the flapper valve to the flush handle has enough slack and is not getting caught or holding the flapper open. If it’s too short, loosen it up a bit to make the toilet flapper close faster.

The flapper chain attaches to the flapper on the lower end and the flushing handle/lever on the upper end. Move it one or two links further out to loosen it. If a lever is used without a chain, adjust it loose.

2. Clean or replace the flapper

Mineral deposits or wear can prevent the flapper from sealing properly. Turn off the water supply and clean the flapper with vinegar or baking soda. If it’s worn, replace the flapper valve.

3. Adjust the water level

The water level in the tank should be 1 inch below the overflow tube. If it’s too high, adjust the float so less water fills the tank.

4. Replace the flush valve

You may need to replace the entire flush valve if the flapper and other adjustments don’t solve the problem. 

5. Fix toilet tank leaks

Listen for running water and inspect for leaks around tank bolts, the overflow tube, and fittings. Fix any leaks found.

6. Clear debris

Ensure valve openings and the siphon jet are clear of obstructions and debris that can prevent proper operation.

7. Replace the fill valve

If needed, replace the entire fill valve assembly that refills the tank after flushing.

Be sure to turn off the water supply first when making repairs. Test between each adjustment. Patience and some trial and error are usually needed to resolve a double-flushing issue.

Frequently Asked Questions

How do you fix a toilet that flushes twice?

If your toilet flushes twice, adjust the toilet flapper to fix the issue. This occurs when the flapper stays open for too long and flushes too much water.

Why would a toilet double flush?

A toilet flushes twice when the toilet valve has not been set to hold the correct amount of water. In this case, excess water gets to the toilet, leading to a second flush.

How do you fix a toilet that doesn’t flush every few flushes?

If your toilet struggles to complete a flush, you can fix it by adjusting the refill valve, cleaning the inlet holes, clearing clogs, fixing the flapper, replacing the outdated toilet itself, or other plumbing issues.

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