Why Your Toilet Keeps Running — 5 Simple Fixes Before Calling a Plumber

It usually starts as a faint trickle you barely notice. Then, a few hours later, it’s constant. That running sound from your toilet that just won’t quit. It can drive you mad after a while. But more than that, it quietly drains water all day and night. You may not realize it, but a running toilet can waste hundreds of litres daily. That’s not just bad for the planet — it also shows up on your water bill.

Most people think fixing it means calling a plumber. In truth, many cases are simple enough to handle yourself. Once you understand what’s happening inside that tank, you can stop the running in a few minutes. Let’s go through the most common reasons this happens and how you can fix each without professional help.

1. The Flapper Isn’t Closing Right

This is the number one cause of a toilet that won’t stop running. The flapper is that rubber piece sitting at the bottom of your tank. It opens when you flush and drops back down to seal the water. Over time, it can warp, crack, or just stop fitting properly.

You can test it easily. Take off the tank lid, then press down on the flapper. If the water sound stops, that’s your issue. Don’t worry, it’s a simple replacement job.

Turn off the water supply valve behind the toilet. Flush to empty the tank, unhook the old flapper, and take it to a nearby hardware shop to match the same one. Put the new flapper in place, reconnect the chain, and turn the water back on. Once the tank refills, listen. If it stays silent, you’ve nailed it.

2. The Float Is Set Too High

Every toilet has a float that tells it when to stop filling. If it’s set too high, water rises past the overflow tube and keeps running endlessly. That’s why you hear that non-stop trickle.

To fix it, look inside your tank. You’ll see a float ball on a rod or a cup on a vertical arm. For a ball float, bend the rod down slightly so the ball sits lower. For a float cup, find the adjustment screw and turn it to lower the float.

The water should stop about an inch below the top of the overflow tube. Do a quick test flush to ensure the tank fills only up to that level. It’s one of those fixes that takes less than five minutes but saves you a lot of wasted water.

3. The Fill Valve Needs Cleaning or Replacement

The fill valve could be next if you’ve ruled out the flapper and float. It’s the part that lets water into the tank and stops it when it reaches the set level. But with time, dirt or mineral buildup can block it from closing correctly.

Here’s what you can do. Lift the float manually while the tank fills. If the water stops, the valve is likely working but just dirty. Shut off the water, remove the top of the valve, and rinse it well. Sometimes a quick clean is all it takes.

If water keeps flowing even when you lift the float, the valve is probably done for. You can replace it easily with a new one. Follow the steps in the package and test it after installation. It’s a small effort that completely stops that constant run.

4. There’s a Leak in the Flush Valve or Overflow Tube

Even if everything else seems fine, a hidden leak might be why your toilet keeps running. The flush valve or overflow tube can crack or loosen, letting water slip quietly from the tank into the bowl.

Here’s a quick way to check. Put a few drops of food colouring into the tank and wait about ten minutes. If the colour appears in the bowl without flushing, you’ve got a leak.

Replacing the flush valve takes more work because you’ll need to remove the tank from the bowl. If you’re comfortable with tools, it’s doable. If not, you can call a plumber once you know the real problem. Either way, diagnosing it first helps you avoid unnecessary costs.

5. The Chain Is Too Tight or Too Loose

It sounds silly, but that little chain inside your tank can cause much trouble. It connects the flush handle to the flapper. If it’s too short, the flapper can’t close fully. It tangles and stops the flapper from sealing if it’s too long.

Open the tank, press the handle, and watch how the chain moves. There should be a tiny bit of slack when the flapper is down — not tight, not dangling. Adjust it by changing which link connects to the handle lever. This little tweak often solves the problem completely.

How to Keep Your Toilet from Running Again

Once you fix the issue, a little maintenance goes a long way. Clean the tank every few months to prevent dirt buildup on the parts. Avoid those drop-in cleaning tablets — they look handy, but wear out rubber seals faster.

If your water is hard, consider using a softener to prevent mineral scale from forming inside the tank. And listen after each flush. If you hear water running longer than usual, check it right away. The earlier you catch it, the easier it is to fix.

When You Really Should Call a Plumber

Sometimes, even after all this, the toilet still keeps running. That usually means a deeper problem — maybe a cracked tank, damaged seal, or an issue with water pressure. These aren’t DIY-level fixes.

A licensed plumber can run a proper check, test the pressure, and replace worn-out parts safely. It might cost more, but it saves you from bigger damage or inflated water bills.

Final Thoughts

A running toilet is one of those problems that looks small but quickly adds up in cost and irritation. The trick is not to ignore it. Most of the time, it’s something simple like the flapper or float. A few minutes and some attention can stop that sound, save litres of water, and cut down your bill.

Don’t wait for it to fix itself — it won’t. Lift the lid, take a look, and handle it right away. You’ll feel better hearing silence again, and your wallet will thank you, too.