A higher-than-usual water bill is rarely random. Toronto Water bills are metered, which means the number reflects actual water usage — and if that number has jumped, there is a specific reason for it. Most causes are fixable, and most involve a plumbing issue rather than a lifestyle change.
Here are the six most common plumbing causes of an unexpectedly high water bill in Toronto.
1. A Running Toilet
This is the single most common cause of an inflated water bill, and the most frequently overlooked because it often isn’t audible.
A toilet that runs continuously can waste between 200 and 700 litres of water per day — that’s 6,000 to 21,000 litres per month, which can add $30 to $100 or more to a monthly Toronto Water bill. A flapper valve that doesn’t seal properly is the most common cause. Water silently fills the tank, overflows into the bowl through the flush valve, and drains away without the homeowner noticing.
The dye test: Add a few drops of food colouring to the toilet tank (not the bowl). Wait 15 minutes without flushing. If colour appears in the bowl, water is leaking past the flapper. Replacing a flapper costs $10 to $20 at a hardware store and takes about 10 minutes.
2. A Leaking Faucet
A faucet dripping once per second wastes approximately 11,000 litres per year — roughly 30 litres per day. That’s less dramatic than a running toilet but still visible in your bill over time, and the drip rate often increases as the washer or cartridge degrades further.
Kitchen and bathroom faucets are the most common culprits. Outdoor hose bibs are easy to forget about and can run for an entire season before being noticed.
3. A Leaking Irrigation System or Outdoor Tap
Outdoor water use is metered in Toronto exactly the same as indoor use. A garden hose left slightly open, a dripping hose bib, or an irrigation system with a cracked head or valve can waste significant water over weeks or months — especially because outdoor leaks often aren’t visible from inside the house.
Walk your property and inspect every outdoor tap and hose connection. Check your irrigation system heads for wet spots in the lawn that don’t match the rest of the grass — these indicate underground supply line leaks.
4. A Hidden Pipe Leak
A supply line leak inside a wall, under a slab, or in a crawl space adds water usage without any visible indicator in the living space until significant damage has already occurred. This is one of the more serious causes because it combines a higher bill with structural water damage that accumulates silently.
If the bill increase is significant and you’ve ruled out toilets, faucets, and outdoor fixtures, do the water meter test: turn off all water-using fixtures and appliances, note the meter reading, and check it again after 15 to 30 minutes. If the meter has moved, you have a leak somewhere in the system.
5. A Failing Water Softener
Homes with a water softener that has a malfunctioning timer or control valve can end up with the regeneration cycle running continuously — which uses large amounts of water and salt. If you have a water softener and your bill has increased significantly, check the regeneration schedule and the brine tank water level.
6. A Hot Water Recirculation System Running Constantly
Hot water recirculation systems pump hot water continuously through the supply lines so that hot water is available immediately at any tap. If the system’s timer or sensor fails, it can run 24/7, significantly increasing both your water usage and gas or hydro bill. Check that the recirculation pump timer is programmed correctly and that the pump is actually stopping during off-hours.
Understanding Your Toronto Water Bill
Toronto Water charges by cubic metre (1,000 litres). The current residential rate in Toronto (as of 2025) is approximately $4.36 per cubic metre, including the water and sewer component. A typical household in Toronto uses 150 to 200 cubic metres per year.
If your bill has increased by 10 to 20 cubic metres in a single billing period with no change in household activity, that points directly to an ongoing leak — not seasonal variation or billing error.
Toronto Water provides a leak detection guide through their website and will sometimes credit one billing period if you can demonstrate you had a leak and have repaired it. Contact Toronto Water directly to ask about the leak adjustment policy.
When to Call a Plumber
If the water meter test shows movement with all fixtures off, call a plumber before the next billing cycle. A hidden leak will not fix itself, and the water damage it causes often exceeds the cost of the repair by a significant margin.
ED Plumbing provides leak detection and repair throughout Toronto and the GTA. Our TSSA-licensed plumbers can locate hidden leaks, repair running toilets, and address any of the causes above — usually same day. Call (437) 260-6342.