Why Does My Toilet Keep Running? Common Causes and When to Call a Plumber

1. The Toilet Flapper Is Worn Out

One of the most common causes of a running toilet is a faulty flapper. The flapper is located inside the toilet tank and creates a seal that keeps water in the tank until you flush.

Over time, the flapper can become worn, warped, cracked, or covered with mineral buildup. When it no longer creates a tight seal, water can continuously leak from the tank into the toilet bowl. The toilet then keeps refilling the tank to replace the lost water.

Replacing a worn toilet flapper is often a relatively simple repair, but if a new flapper doesn't solve the problem, another component may be responsible.

2. The Flapper Chain Is Too Short or Too Long

The chain connecting your toilet handle to the flapper also plays an important role in how your toilet operates.

If the chain is too short, it may prevent the flapper from closing completely. If it is too long, the chain can become tangled or caught underneath the flapper.

Either problem can prevent the toilet from sealing properly and cause water to continue running after you flush.

3. The Fill Valve Isn't Working Properly

The fill valve controls the flow of water into your toilet tank. After you flush, the valve allows the tank to refill and then shuts the water off once it reaches the correct level.

A damaged or worn fill valve may fail to shut off completely. When this happens, you might hear your toilet running continuously or periodically throughout the day.

A malfunctioning fill valve may need to be adjusted or replaced by a plumber.

4. The Float Is Set Too High

Inside your toilet tank is a float that helps determine when the fill valve should stop adding water.

If the float is positioned too high, the toilet tank may continue filling until water flows into the overflow tube. This creates a constant cycle where water enters the tank and immediately drains away.

Adjusting the float may solve the problem. However, if the float or fill valve is damaged, replacing the affected components may be necessary.

5. Water Is Flowing Into the Overflow Tube

The overflow tube is designed to prevent water from spilling out of the toilet tank if the water level becomes too high.

Normally, the water inside your tank should stop below the top of the overflow tube. If you can see water continuously flowing into the tube, there is likely an issue with the fill valve, float, or water level adjustment.

Ignoring this problem means your toilet may continue wasting water even though there is no visible leak outside of the tank.

6. The Flush Valve Seal Is Damaged

If replacing or adjusting the flapper doesn't stop your toilet from running, there may be an issue with the flush valve or its seal.

Damage, corrosion, mineral deposits, or normal wear can prevent the flush valve from creating a watertight seal. Repairing this part of the toilet can be more involved than replacing a basic flapper and may require professional plumbing service.

Can a Running Toilet Increase Your Water Bill?

Yes. A toilet that continuously allows water to move from the tank into the bowl can waste water around the clock.

Even a toilet that only runs occasionally can add unnecessary water usage over time. If you've noticed an unexplained increase in your water bill, checking your toilets for leaks and running water is a good place to start.

One simple way to check for a slow toilet leak is to place a few drops of food coloring in the toilet tank without flushing. Wait approximately 15 to 20 minutes. If the colored water appears in the bowl, water is leaking from the tank into the bowl.

Should You Repair or Replace a Running Toilet?

Not every running toilet needs to be replaced.

If the problem is caused by a worn flapper, chain, fill valve, or another replaceable component, repairing the toilet can often restore normal operation.

Replacement may make more sense if the toilet is older, frequently needs repairs, has cracks or damage, or continues experiencing problems despite previous repairs. A plumber can inspect the toilet and help determine whether repair or replacement is the more practical option.

When Should You Call a Plumber for a Running Toilet?

Some toilet problems are easy to identify, but you don't want to repeatedly replace parts without solving the actual issue.

Consider calling a professional plumber if:

• Your toilet runs constantly
• The toilet starts running randomly throughout the day or night
• You've replaced the flapper but the toilet still runs
• Water continuously flows into the overflow tube
• The toilet has trouble flushing properly
• You notice water leaking around the toilet
• Your water bill has unexpectedly increased
• The toilet frequently needs repairs

A professional plumber can identify the source of the problem and determine which components need to be repaired or replaced.

Get Professional Toilet Repair From TLH Plumbing

A running toilet isn't just annoying. It can waste water, increase your utility bills, and indicate that components inside your toilet are no longer working correctly.

If your toilet won't stop running, let the professionals at TLH Plumbing find the problem and provide the right repair. Whether you need a simple toilet repair, replacement components, or a new toilet installation, our experienced plumbers are ready to help.

Contact TLH Plumbing today to schedule professional toilet repair and get your bathroom plumbing working properly again.