Running Toilet? How to Detect, Fix, and Prevent Leaks

Summary:

A running toilet can waste hundreds of litres of water each month and increase your water bill.
Common causes: worn flush valve, faulty fill valve, or a cracked flapper.
Check for leaks by listening for water, using food colouring in the tank, or inspecting the bowl with a flashlight.
You can often replace valves yourself, but persistent leaks may require a licensed plumber.
Fixing the issue promptly saves water, protects your home, and prevents costly damage.

Why Fixing a Running Toilet Matters

Even small leaks add up. A running toilet can waste thousands of litres of water per year, increasing your water bill and impacting the environment. Checking your toilet regularly helps you save money and avoid bigger plumbing problems down the line.

Common Causes of a Running Toilet

Worn Flush Valve – If the flush valve doesn’t close properly, water leaks continuously from the tank into the bowl.
Faulty Fill Valve – Mineral deposits or wear can prevent the fill valve from shutting off completely.
Other Issues – Cracked flappers, misaligned floats, or loose parts may also cause leaks.

How to Spot a Running Toilet

Obvious signs:

You hear water running even when the toilet hasn’t been used.

Silent leaks:

Add a few drops of food colouring to the tank, wait 15–20 minutes without flushing. If the bowl water changes colour, there’s a leak.
Inspect the inside of the bowl with a flashlight. Continuous streaks of water along the sides indicate a leak.

DIY Fixes vs. Calling a Plumber

Simple DIY Fixes:

Replacing the flush valve or fill valve is often straightforward. Hardware stores carry the parts you need.
Always follow the manufacturer’s instructions carefully.

When to Call a Licensed Plumber:

The leak continues after a DIY fix.
You’re unsure of the cause.
Signs of water damage appear in the bathroom.

Repairing a running toilet promptly conserves water, protects your home, and keeps your water bill in check.

Protect Your Home and Water Bill

Experiencing plumbing issues? Call on Reliance™. Learn more about our plumbing protection and maintenance plans to stay prepared and protect your home from unexpected problems.