How to Stop a Running Toilet

A running toilet is more than just an annoyance — it can waste up to 750 litres of water per day, significantly inflating your water bill. This is a particularly common issue in older Canadian homes where toilet components haven't been updated in years. Fortunately, the fix is usually simple and inexpensive.

The most likely culprit is a deteriorated flapper valve at the bottom of the tank. The flapper creates a seal that holds water in the tank between flushes. When it warps or develops mineral buildup, water continuously leaks into the bowl. A faulty fill valve that doesn't shut off properly, or an improperly adjusted float, can also cause continuous running.

A replacement flapper (CAD $5–$12), replacement fill valve if needed (CAD $12–$20), adjustable pliers, a sponge and bucket for excess water, and towels. All parts are universally available at Home Depot, Canadian Tire, and Rona.

1. Remove the tank lid and set it aside on a towel.
2. Check the flapper — press it down with your finger. If the running stops, the flapper needs replacing.
3. Turn off the supply valve (usually on the wall behind the toilet).
4. Flush to empty the tank, then sponge out remaining water.
5. Unhook the old flapper from the overflow tube ears and disconnect the chain.
6. Install the new flapper, reconnect the chain (leaving about 1 cm of slack), and turn the water back on.
7. If the problem persists, adjust the float by turning the adjustment screw on the fill valve so the water level sits about 2.5 cm below the overflow tube.

If you've replaced the flapper and adjusted the fill valve but the toilet still runs, there may be a crack in the overflow tube or a problem with the flush valve seat. A licensed plumber can diagnose and repair these issues efficiently, and can also check for hidden leaks at the base of the toilet.