How to Fix a Running Toilet in Toronto: When to DIY and When to Call a Plumber

What Causes a Toilet to Run Constantly?

A toilet's flushing mechanism is elegantly simple: when you push the handle, it lifts a rubber flapper at the bottom of the tank, releasing stored water into the bowl. As the tank empties, a float drops, which opens a fill valve that refills the tank with fresh water. When the float rises to the correct level, the fill valve closes and everything stops — until you flush again.

When a toilet runs constantly, it means water is moving when it shouldn't be. There are three main culprits responsible for the vast majority of running toilet cases:

• A worn or warped flapper — the rubber disc at the bottom of the tank that seals the flush valve opening. When rubber degrades, it no longer forms a watertight seal, and water trickles continuously into the bowl.
• A misadjusted or faulty fill valve — the mechanism that controls water entering the tank. If it doesn't shut off fully, water keeps running and typically overflows into the overflow tube.
• An incorrect float position — if the float is set too high, water reaches the overflow tube before the fill valve shuts off, causing a continuous trickle that never stops.

Identifying which of these three is causing your problem is the critical first step — and it's something you can do yourself in about five minutes.

The Running Toilet Water Waste Problem in Toronto

Toronto operates one of North America's best water systems, but it isn't free. Toronto Water bills residential customers based on volume consumed, and the rates have increased significantly over the past decade. As of recent years, residential water rates in Toronto run approximately $3.80 to $4.20 per cubic metre (1,000 litres) when you factor in the water and wastewater combined charge.

A toilet running continuously at a moderate drip-to-trickle rate wastes roughly 150 to 200 litres per day. At Toronto's rates, that equates to approximately $600 to $750 per year in wasted water — for a problem that a $5 flapper from Canadian Tire can often fix. At worst-case running rates — a fully open flapper — a toilet can waste up to 757 litres (200 US gallons) per day, pushing the annual waste cost well over $1,000.

Beyond the dollar cost, this is thousands of litres of treated drinking-quality water sent straight to the sewer doing nothing useful. Most Toronto homeowners are shocked when they calculate how much a running toilet actually costs them annually. The fix is almost always fast and inexpensive — the waste comes from delaying action. If you notice the toilet is also draining sluggishly alongside the running issue, professional drain cleaning may be needed to address a separate blockage in the drain line.

Diagnosing Which Part Is Causing Your Running Toilet

Before buying any parts, diagnose the specific problem. The dye test is the most reliable method for identifying a leaking flapper. Drop a dye tablet (available at hardware stores) or a few drops of food colouring into the toilet tank — do not flush. Wait 15 minutes without using the toilet. If colour appears in the bowl, water is leaking through the flapper. If the bowl stays clear, the flapper is likely fine.

To diagnose the fill valve and float, remove the tank lid and observe what happens after a flush. Listen for hissing — a constant hissing sound indicates the fill valve is running. Watch the water level: if it rises to the top of the overflow tube (the tall vertical tube in the centre of the tank) and flows down into it, your float is set too high or the fill valve isn't shutting off. You'll see a small trickle going down the overflow tube continuously.

Mark the current water level with a pencil on the inside of the tank. The water level should sit approximately 1 to 2 centimetres below the top of the overflow tube. If it's at or above the overflow tube opening, you need to adjust or replace the float assembly.

DIY Fix 1: Replacing a Worn Flapper

A worn flapper is the cause of roughly 70% of running toilet problems — and replacing one is the easiest plumbing repair any homeowner can attempt. The part costs between $5 and $15 at any Toronto hardware store, including Canadian Tire, Home Depot, Rona, or a local plumbing supply house. The job takes about 20 minutes.

Step-by-step flapper replacement:

1. Turn off the water supply. The shutoff valve is located on the wall behind the toilet near the floor. Turn it clockwise until it stops. Flush the toilet to empty the tank.
2. Remove the old flapper. Most flappers clip onto two pegs on either side of the flush valve seat. Unclip the sides and unhook the chain from the flush handle arm. The flapper slides off.
3. Inspect the flush valve seat. Run your finger around the rubber seat the flapper closes against. If it's rough, pitted, or has visible mineral deposits, clean it with fine steel wool or replace the entire flush valve assembly.
4. Install the new flapper. Clip the new flapper onto the pegs on either side. Reattach the chain to the flush handle arm, leaving about 1 to 2 centimetres of slack — enough that the flapper closes fully but lifts completely when you flush.
5. Turn the water back on and observe the refill. After one flush, check that the flapper seats properly and no water is trickling through.

At a Toronto hardware store, bring the old flapper if possible — staff can match it to the correct replacement. Most modern toilets use a universal 2-inch or 3-inch flapper, but older Canadian-market toilets may use non-standard sizes. Fluidmaster and Korky are reliable brands available at every major hardware retailer in the GTA.

DIY Fix 2: Adjusting or Replacing the Float

If the dye test showed no leakage through the flapper but water is trickling into the overflow tube, the float needs adjustment. There are two main float types found in Toronto homes:

Ball float (older design): A large plastic or rubber ball on the end of a metal arm. To lower the water level, bend the arm downward slightly — this lowers the position at which the float shuts off the fill valve. The target level is 1 to 2 centimetres below the overflow tube opening. Some ball floats have an adjustment screw at the fill valve end of the arm instead.

Cup float (modern design): A cylindrical float that rides up and down on the fill valve body itself. Adjust by pinching the side clip or turning an adjustment screw, which lowers or raises the cutoff point. Most cup floats have a clearly marked adjustment mechanism — usually a twist of the top of the float assembly.

If the float is waterlogged (ball float filling with water and riding low), replace it. A waterlogged ball float will never adjust correctly because it can't reach its proper buoyancy level. The replacement assembly is $10 to $25 at any hardware store.

DIY Fix 3: Replacing the Fill Valve

If adjusting the float doesn't stop the running, or if the fill valve itself is hissing or cycling repeatedly even after the tank is full, the fill valve needs replacement. This is a slightly more involved repair than flapper replacement, but still firmly within DIY territory for any homeowner comfortable working with basic tools.

Fill valve replacement steps:

1. Turn off the supply valve and flush the toilet to empty the tank. Use a sponge or towel to remove remaining water from the tank bottom.
2. Disconnect the water supply line from the bottom of the tank (have a small bucket ready — there will be some residual water).
3. Unscrew the locknut on the outside bottom of the tank that holds the fill valve in place. Most unscrew counterclockwise by hand or with pliers.
4. Lift the old fill valve out of the tank.
5. Install the new fill valve — Fluidmaster 400A is the standard replacement used by Toronto plumbers — following the included instructions. Set the height to match your tank depth.
6. Reconnect the supply line, turn on the water, and adjust the water level per the instructions.

The entire job typically takes 30 to 45 minutes. A quality replacement fill valve costs $15 to $35. If you're replacing the fill valve, many plumbers recommend replacing the flapper at the same time — the total parts cost is under $30, and you eliminate two potential failure points in a single service.

When You Need to Call a Licensed Toronto Plumber

While the three repairs above cover the majority of running toilet situations, there are circumstances where a professional toilet repair in Toronto is the right call:

• Cracked tank or bowl. Any visible crack in the porcelain — even a hairline crack — is a sign of impending failure. A cracking toilet tank can fail suddenly, releasing gallons of water. This is a replacement situation, not a repair.
• Supply line issues. If the braided stainless or plastic supply line connecting the shutoff valve to the toilet base is corroded, kinked, or leaking at its connections, it needs replacement. Old compression-style supply lines in Toronto homes have a failure rate that increases significantly after 10 years.
• Shut-off valve fails to close fully. If the shutoff valve behind the toilet is stuck open or won't close completely, you cannot safely shut off water to the toilet without closing the main shutoff for the whole home. A plumber needs to replace the shutoff valve.
• Recurring problems after DIY repairs. If you've replaced the flapper twice in the past year and it keeps failing, the flush valve seat is likely damaged or corroded and needs a full flush valve replacement — a more complex job best left to a professional.
• Leak at the base of the toilet. Water pooling around the toilet base indicates a failed wax ring seal between the toilet and the drain flange. This requires removing the toilet, replacing the wax ring, and properly reseating the unit — a job that requires experience to do correctly. In some older Toronto homes, this type of recurring leak near the base can indicate a deeper issue with the sewer line connection that a licensed plumber should inspect.

The Toilet Repair vs. Replacement Decision

Before spending money on repairs, consider the age and condition of your toilet. Toilets manufactured before 2000 typically use 13 litres (3.5 gallons) per flush or more. Current Canadian plumbing code requires toilets to use a maximum of 6 litres per flush, and the highest-efficiency models use as little as 4.8 litres. If your toilet is more than 15 to 20 years old and requires repairs, replacement often makes more economic and environmental sense than continued investment in an old, inefficient unit.

The break-even calculation is straightforward: if repair costs exceed $200 to $300 on a toilet that's 15+ years old, a new toilet at $300 to $600 (plus installation) frequently pays for itself within two to three years in reduced water consumption alone. A Toronto plumber can run through the numbers with you and give a professional recommendation based on the specific condition of your toilet.

Water-Efficient Toilet Upgrades Available in Toronto

If replacement makes sense, Toronto homeowners have access to excellent water-efficient options. Dual-flush toilets — with separate half-flush (3L) and full-flush (6L) modes — are standard in many newer GTA homes and offer significant water savings over single-flush designs. WaterSense-certified toilets use 4.8 litres or less per flush while meeting or exceeding performance standards.

The City of Toronto has historically offered rebate programs for high-efficiency toilet replacements through its WaterSaver program. While rebate programs change year to year, the city has offered between $60 and $100 per qualifying toilet installation. Visit toronto.ca/services-payments/water-environment/paid-water-services/watersaver-home/ for current program details and eligible products.

Popular brands available through Toronto plumbing suppliers include Toto, Kohler, American Standard, and Duravit. Your licensed plumber can source and install any of these, and many carry them at competitive pricing without the markup you'd see at a big-box retail store.

How Much Does Toilet Repair Cost in Toronto?

For a straightforward toilet repair — flapper, fill valve, or float replacement — expect to pay between $100 and $200 for a licensed Toronto plumber's service call, including labour and parts. Wax ring replacements typically run $200 to $350, depending on accessibility and whether the floor flange needs any repair work. Shutoff valve replacement adds $100 to $200 to any service call.

For a new toilet supply and installation, costs run $500 to $900 for a mid-range toilet (Toto Drake, Kohler Cimarron, or equivalent) fully installed by a licensed plumber, including removal and disposal of the old unit. High-end toilets — elongated, comfort height, or bidet-integrated models — can push installation costs to $1,200 to $2,000. Any emergency plumbing service in Toronto that arrives after-hours will charge a premium on top of standard rates — another reason to address a running toilet promptly rather than waiting for a crisis.

Frequently Asked Questions

How much water does a running toilet waste per day in Toronto?

A running toilet in Toronto typically wastes between 150 and 200 litres of water per day, though a severely running toilet with a fully open flapper can waste up to 757 litres (200 gallons) daily. At Toronto's combined water and wastewater rates, that translates to $600 to $1,000+ in wasted water annually. Given that a flapper replacement costs $5 to $15 in parts, the repair pays for itself hundreds of times over. There is no good reason to delay fixing a running toilet.

Can I fix a running toilet myself without plumbing experience?

Yes — the three most common running toilet causes (worn flapper, misadjusted float, faulty fill valve) are all DIY-friendly repairs that require no special tools or plumbing experience. The parts cost under $30 at any Toronto hardware store, and step-by-step instructions come in the packaging. The only prerequisites are the ability to turn a valve and follow basic instructions. The one skill that genuinely matters is correctly diagnosing which component is faulty before buying parts — this guide and the dye test described above will get you there.

How long does it take to fix a running toilet?

Replacing a toilet flapper takes 15 to 20 minutes, including shutting off the water, removing the old part, and installing the new one. Fill valve replacement takes 30 to 45 minutes. Float adjustment takes under 10 minutes once you've identified the problem. A licensed plumber doing a service call for a running toilet typically completes the repair within 30 to 60 minutes. The diagnosis can sometimes take longer than the actual fix — which is why proper diagnosis before purchasing parts is time and money well spent.

What's the difference between a flapper and a fill valve?

The flapper is the rubber seal at the bottom of the toilet tank that opens to release water into the bowl when you flush and closes to stop flow as the tank refills. The fill valve is the mechanism on the side of the tank that controls the flow of fresh water into the tank during refilling. The flapper controls water going out of the tank into the bowl; the fill valve controls water coming into the tank from the supply line. They are separate components with separate failure modes, though both can cause a running toilet with similar symptoms — which is why proper diagnosis matters.

Is there a Toronto rebate for replacing an old toilet?

The City of Toronto has offered toilet replacement rebates through its WaterSaver program, historically providing $60 to $100 per qualifying high-efficiency toilet. Eligible toilets must use 4.8 litres per flush or less and meet WaterSense or equivalent certification standards. Program availability and rebate amounts change annually depending on city budget allocations. Visit toronto.ca or call 311 for current program details. Your licensed plumber can also advise on eligible models at the time of your installation consultation.