Why it matters to the pipes
A running toilet is easy to ignore, especially if the sound is faint. Yet a steady leak from tank to bowl can waste a great deal of water every day and show up clearly on your water bill. Since Toronto charges for water by metered use, finding the cause pays for itself. The good news is that almost every toilet that keeps running traces back to the flapper, the float, or the fill valve.
Have to hand
- A flashlight and a bucket
- Old towels and a pair of gloves
- The way to the main valve
Put the tools down if
- Water will not stop at the valve
- Sewage rises in a floor drain
- You smell gas near the heater
The steps, in order
- Take off the tank lid and lay it flat on a towel, since cistern lids crack if knocked.
- Check the water level. Water trickling over into the upright overflow pipe means the float is set too high.
- Adjust the float. Lower a ball float by bending its arm, or slide a cup float down its rod, until the water settles some two to three centimetres under the rim of the overflow pipe.
- Test the flapper. Tint the tank water with a drop or two of dye and leave the handle untouched for a quarter of an hour. Should the tint reach the pan, the flapper is passing water.
- Replace the flapper. Close the stop under the cistern, flush once so it drains, unclip the worn flapper and clip on one of the same size.
- Check the chain. Leave a finger-width of droop in it. Pulled taut, it lifts the flapper; left long, a link can get trapped under the seal.
- Replace the fill valve if it hisses constantly or fails to shut off after adjustment.
Common missteps
- Buying a universal flapper without checking the size; tanks use two-inch or three-inch openings.
- Overtightening plastic nuts on the supply line or fill valve, which can crack them.
- Forcing a seized supply valve under the toilet. If it will not turn, use the main shut-off instead.
- Using drop-in bleach tablets, which can wear down rubber parts faster.
When to ring for help
Call if the tank leaks onto the floor, the toilet rocks, water seeps from the base, or the supply valve will not close. These point to failed seals or bolts that need more than a part swap. While a plumber is in the house, it is often sensible to have a look at other aging equipment; for instance, a noisy or leaking tank in the basement may be due for gas water heater replacement.
If the toilet fills slowly rather than running, the cause may be pressure; see our guide to low water pressure.
Older toilets and replacement
Toilets installed before the mid-1990s often use far more water per flush than modern models. If yours is very old and the parts are hard to find, replacing the whole toilet may make more sense than repairing it. A modern low-flow toilet can save water with each flush while still clearing waste well, provided it is a reputable model with good performance ratings.