How to Fix a Running Toilet

Introduction

A running toilet is more than just an annoyance—it can waste hundreds of gallons of water per day, significantly increasing your utility bill. The good news is that most running toilet issues are easy to fix with basic tools and minimal plumbing experience. In this guide, we’ll walk you through five easy steps to stop your toilet from constantly running and get it back to working efficiently.

Step 1: Identify the Cause

Before diving into repairs, it’s important to understand what’s causing your toilet to run. The most common reasons include:

• Worn-out or misaligned flapper – The rubber flapper in the tank may not be sealing properly, allowing water to continuously leak into the bowl.
• Faulty fill valve – The fill valve regulates how much water enters the tank. If it’s malfunctioning, the tank may constantly refill.
• Incorrect float height – The float determines the water level inside the tank. If it’s set too high, excess water will keep draining into the overflow tube.
• Leaky or tangled chain – If the chain connecting the flush handle to the flapper is too long, too short, or tangled, the flapper may not seal properly.

Once you've pinpointed the problem, you can move on to fixing it.

Step 2: Check and Replace the Flapper

The flapper is one of the most common culprits of a running toilet. Here’s how to inspect and replace it if needed:

• Turn off the water supply to your toilet. The shutoff valve is usually located near the base of the toilet.
• Remove the toilet tank lid and flush to empty most of the water.
• Inspect the flapper—if it’s worn, cracked, or not sealing properly, it needs to be replaced.
• Unhook the old flapper from the chain and side hinges.
• Attach a new flapper, making sure it fits snugly over the flush valve.
• Turn the water back on and test the toilet.

Flappers are inexpensive and can be found in most hardware stores or in a Universal Plumbing Repair Kit.

Step 3: Adjust the Chain Length

If the chain connecting the flush handle to the flapper is too long, it can get caught under the flapper, preventing a proper seal. If it’s too short, it won’t allow the flapper to close fully.

To fix the chain:

• Check the chain’s length—it should have about half an inch of slack when the flapper is closed.
• If it’s too long, adjust it by clipping the chain a few links shorter.
• If it’s too short, move the clip to give it more length.
• Flush the toilet to test the new chain length.

This small adjustment can often fix a running toilet instantly.

Step 4: Adjust or Replace the Float

The float controls the water level in the toilet tank. If the water level is too high, excess water will flow into the overflow tube, causing the toilet to run.

To adjust the float:

• For a ball float (older toilets): Bend the metal rod slightly downward to lower the water level.
• For a cup-style float (modern toilets): Locate the adjustment screw on the fill valve and turn it counterclockwise to lower the float.

If the float is damaged or continues to malfunction, it may need to be replaced.

Step 5: Replace the Fill Valve (If Necessary)

If you’ve checked the flapper, chain, and float but your toilet is still running, the fill valve may be the issue. Over time, fill valves wear out and fail to shut off the water supply properly.

Here’s how to replace it:

• Turn off the water supply and flush the toilet to drain the tank.
• Use an adjustable wrench to unscrew the old fill valve from the bottom of the tank.
• Install the new fill valve according to the manufacturer’s instructions, ensuring the water level is set correctly.
• Turn the water back on and test the toilet.

If you're unsure which fill valve to buy, a Universal Plumbing Repair Kit usually includes a compatible replacement.

Bonus Tip: Check for Hidden Leaks

If your toilet is still running, you may have a slow leak that’s hard to detect. To test for leaks:

• Add a few drops of food coloring into the toilet tank.
• Wait 15–20 minutes without flushing.
• If the colored water appears in the toilet bowl, your toilet is leaking and still needs repair.

Conclusion

A running toilet is a common household issue that can lead to wasted water and high utility bills if left untreated. Fortunately, with a few simple steps—like replacing the flapper, adjusting the chain, lowering the float, or installing a new fill valve—you can fix the problem quickly and affordably.

If you’d rather leave the repairs to a professional, HandyHelp is here to assist you! Our expert plumbers can diagnose and fix any toilet issues efficiently, ensuring your plumbing runs smoothly. Contact us today for fast and reliable service!