How Much Does It Cost to Fix a Running Toilet?

Scope of this guide: This page is the pricing guide: it explains repair-cost drivers and quote decisions. For diagnosis and step-by-step adjustments, use the linked running-toilet repair guide.

A toilet that runs constantly wastes hundreds of gallons of water per day and adds $10-$30 or more to your monthly water bill. The good news: most running toilet repairs cost under $50 in parts - and are one of the easier DIY plumbing jobs.

Running Toilet Repair Cost

DIY repair cost: $5-$50 in parts Plumber cost: $100-$250 total Parts only (fill valve + flapper kit): $15-$40 at hardware stores

If you're at all comfortable with basic home repairs, this is one worth doing yourself.

What Causes a Toilet to Run?

A running toilet is almost always one of three problems:

1. Worn or warped flapper (most common) The flapper is the rubber seal at the bottom of the tank that lifts when you flush and seals when the tank refills. If it's worn, it doesn't seal properly and water continually leaks into the bowl.

How to check: Put a few drops of food coloring in the tank. Wait 15 minutes without flushing. If color appears in the bowl, the flapper is leaking.

Cost to fix: $5-$15 for a replacement flapper. 10-minute DIY job.

2. Failing fill valve The fill valve controls how water enters the tank after flushing. If it's worn, it may not shut off completely - you'll hear a hissing sound from the tank.

Cost to fix: $10-$25 for a new fill valve. 20-30 minute DIY job.

3. Float set too high If the water level in the tank is above the overflow tube, water constantly drains into the bowl through the overflow. You can see this by lifting the tank lid - water should sit about 1 inch below the top of the overflow tube.

How to fix: Adjust the float arm (older ballcock style) or the adjustment screw on a newer fill valve. Free fix, takes 2 minutes.

DIY Repair Guide: Flapper and Fill Valve

Tools needed: None, or adjustable pliers for the water supply line

1. Turn off the shutoff valve under the toilet
2. Flush to empty the tank
3. Note the make/model of the existing valve if visible, or bring the old flapper to match it
4. Replace the flapper by unclipping the old one from the pegs on the overflow tube and snapping the new one in
5. Reconnect the chain (should have about 1/2 inch of slack)
6. For fill valve: disconnect supply line, unscrew old valve, install new valve per instructions
7. Turn water back on and watch the fill and shutoff

Most flapper replacements take 10 minutes. Fill valve replacement takes 30 minutes on a first attempt.

When to Call a Plumber

Call a plumber when: - You've replaced the flapper and fill valve and the toilet still runs - The shutoff valve under the toilet is stuck and won't close - There's a crack in the overflow tube or the tank itself - Water is leaking from the base of the toilet (separate issue - wax ring)

These situations go beyond the simple repair and benefit from professional diagnosis.

Prevent Future Running

• Replace flappers every 3-5 years proactively - they degrade even without a problem showing
• Use the color-test check annually to catch slow leaks before they become constant runs
• Avoid drop-in tank tablets with bleach - they speed up flapper degradation

How Much Water Is a Running Toilet Wasting?

A constantly running toilet wastes 200-400 gallons per day. At California water rates ($0.01-$0.02+ per gallon), that's $2-$8 per day - or $60-$240 per month. A $15 flapper pays for itself in the first day.

Bottom Line

Fixing a running toilet costs $5-$15 in parts if you DIY, or $100-$250 for a plumber. The repair is almost always a flapper, a fill valve, or a float adjustment. For most homeowners, this is the most accessible DIY plumbing job - no special tools, no turning off the main, and the stakes of making a mistake are very low.

Sources and editorial notes

Prices and permit requirements vary by location, property, equipment, and scope. Treat price ranges as planning estimates and confirm current requirements with the relevant authority and contractor.

• California Contractors State License Board - when a contractor license is required

Related guides

• How to Stop a Toilet from Running (Step-by-Step)
• Toilet Replacement Cost: Supply, Labor, and What to Watch For
• How to Replace a Toilet Flapper (Step-by-Step)

Next step

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