How to Fix a Running Toilet (DIY Guide)

Last updated: March 2026

By the Plumbing Price Guide Team

A running toilet is one of the most common household plumbing problems, and it is almost always fixable without calling a plumber. Most running toilets are caused by a worn flapper valve that costs $3 to $8 and takes five minutes to replace. Even a complete fill valve swap costs under $15 in parts and takes 15 to 30 minutes. This guide walks through every step of diagnosing the cause, choosing the right fix, and completing the repair yourself. For homeowners who prefer professional help, toilet repair typically runs $100 to $250 including the service call.

For full toilet repair pricing, see our toilet repair cost guide. For hourly plumber rates, see plumber cost per hour. Not sure what is going on with your plumbing? Try our plumbing diagnostic tool. For general plumbing costs, see the plumbing cost guide.

How Much Water Does a Running Toilet Waste?

A running toilet is not just an annoying sound. It is a constant drain on your water bill and local water supply. A toilet that runs continuously can waste 200 or more gallons of water per day. That translates to roughly 6,000 gallons per month, which adds $50 to $100 or more to a typical water bill depending on local rates.

Even a "silent" leak, where water slowly seeps past the flapper without making an audible sound, wastes 30 to 50 gallons per day. Over a year, that adds up to more than 10,000 gallons of wasted water. The food coloring test described below is the only reliable way to detect a silent leak.

Beyond the financial cost, wasted water strains municipal water systems and, in areas with septic systems, can overload the drain field. A running toilet is one of those repairs that pays for itself almost immediately. A $5 flapper can save $50 to $100 per month on the water bill.

The U.S. Environmental Protection Agency estimates that household leaks waste nearly 1 trillion gallons of water annually across the country. Running toilets are the single largest source of residential water waste. Fixing a running toilet is one of the simplest and most impactful conservation steps a homeowner can take.

How a Toilet Works

Understanding how a toilet works makes diagnosing a running toilet much easier. A standard gravity-flush toilet has only a few moving parts, all located inside the tank. No electricity, no complex mechanisms. Just water and gravity.

When you press the flush handle, a lever inside the tank lifts a chain connected to the flapper. The flapper is a rubber seal at the bottom of the tank that covers the flush valve opening. When the flapper lifts, water rushes from the tank into the bowl through the flush valve. Gravity carries the water and waste from the bowl down the drain.

Once the tank empties, the flapper drops back down and seals the flush valve opening. The fill valve then activates, refilling the tank with fresh water through the supply line. As the tank fills, the float rises with the water level. When the float reaches a preset height, it signals the fill valve to shut off. The tank is full and ready for the next flush.

The overflow tube is a safety feature. It is a vertical pipe in the center of the tank that prevents overfilling. If the fill valve fails to shut off, excess water flows down the overflow tube and into the bowl rather than flooding the bathroom floor.

A running toilet means one of these components is not working correctly. Either the flapper is not sealing, the fill valve is not shutting off, the float is set too high, or the overflow tube has an issue. The good news is that every one of these parts is inexpensive and designed to be replaced by homeowners.

How to Diagnose Why Your Toilet Is Running

Before replacing any parts, spend two minutes diagnosing the actual cause. There are four possible culprits, and each one has a different fix. Starting with the right diagnosis saves time and avoids buying parts you do not need.

Step 1: The Food Coloring Test (Flapper Check)

This is the single most useful diagnostic test for a running toilet. Remove the tank lid and add 5 to 10 drops of food coloring to the tank water. Do not flush. Wait 15 minutes, then check the bowl. If the water in the bowl is now tinted with color, the flapper is leaking. This is the cause roughly 80% of the time.

If no color appears in the bowl after 15 minutes, the flapper is sealing correctly and the problem is elsewhere. Move on to the next check.

Step 2: The Overflow Tube Check (Float and Fill Valve)

Remove the tank lid and look at the water level relative to the overflow tube. The overflow tube is the tall, open-topped pipe in the center of the tank. The water level should sit about one inch below the top of this tube.

If water is flowing into the overflow tube, the float is set too high or the fill valve is not shutting off. Try adjusting the float first (see Fix 2 below). If adjusting the float does not stop the water from reaching the overflow tube, the fill valve needs replacement.

Step 3: The Chain Check

Look at the chain connecting the flush handle lever to the flapper. If the chain is too short, it can hold the flapper slightly open, allowing water to leak continuously. If the chain is too long, it can get caught under the flapper when it closes, preventing a proper seal.

The correct chain length leaves about half an inch of slack when the flapper is seated. This is a free fix that takes 30 seconds. Simply adjust the clip on the chain to change the length. If the chain is rusted, kinked, or tangled, replace it. Replacement chains cost $2 to $4 and come included with most flapper kits.

Step 4: Listen and Look

Sit quietly and listen. A hissing sound usually points to the fill valve. A trickling or dripping sound suggests the flapper. If the toilet runs intermittently (sometimes called "phantom flushing"), the flapper is slowly leaking. The tank water level gradually drops until the fill valve kicks in to refill it. This cycle repeats every few minutes.

If the toilet runs constantly without stopping, the fill valve is likely stuck open or the float is set too high. Water is flowing into the tank faster than it can drain through the flapper leak, so the overflow tube carries the excess into the bowl nonstop.

Fix 1: Replace the Flapper ($3 to $8, 5 Minutes)

The flapper is the most common cause of a running toilet. It is a soft rubber or silicone seal that sits over the flush valve opening at the bottom of the tank. Over time, the rubber deteriorates, warps, or collects mineral deposits that prevent a watertight seal. Replacing the flapper is the simplest toilet repair and requires no tools.

What You Need

• Replacement flapper ($3 to $8)
• Towel or rag (for drips)
• No tools required

Step-by-Step Instructions

1. Turn off the water supply. Locate the shutoff valve on the wall or floor behind the toilet, near the base on the left side. Turn the oval or round handle clockwise until it stops. This shuts off water to the toilet only; the rest of the house is unaffected.

2. Flush the tank. Press the flush handle to drain most of the water from the tank. Some water will remain at the bottom. You can sponge it out or leave it; a small amount will not cause problems.

3. Remove the old flapper. The flapper hooks onto two small pegs on either side of the overflow tube. Pull the flapper ears off the pegs. Disconnect the chain from the flush handle lever by unhooking the clip. Remove the old flapper entirely.

4. Inspect the flush valve seat. Run your finger around the rim of the flush valve opening where the flapper sits. If the surface feels rough, pitted, or corroded, the new flapper may not seal properly. Light mineral buildup can be cleaned with fine emery cloth or a scrub pad. If the seat is cracked or severely damaged, the entire flush valve needs replacement (see Fix 4 below).

5. Install the new flapper. Hook the new flapper ears onto the same pegs on the overflow tube. Attach the chain to the flush handle lever with the clip. Adjust the chain length so there is about half an inch of slack when the flapper is seated closed. Too much slack and the chain can get caught under the flapper. Too little and the flapper will not seal completely.

6. Turn the water back on. Open the shutoff valve by turning it counterclockwise. Let the tank fill completely. Flush the toilet two or three times to verify the flapper seals properly and the running has stopped. Repeat the food coloring test to confirm there is no leak.

Choosing the Right Flapper

Flappers come in two standard sizes: 2-inch and 3-inch. Most older toilets (pre-2005) use 2-inch flappers. Many newer toilets, especially high-efficiency models, use 3-inch flappers. The easiest way to identify the size is to look at the existing flapper or check your toilet model number, which is usually stamped inside the tank near the waterline or behind the seat hinges.

Universal flappers from brands like Korky and Fluidmaster fit most standard toilets. However, some manufacturers (Kohler, American Standard, TOTO) use proprietary flapper designs for certain models. If a universal flapper does not seal properly, check whether your toilet requires a brand-specific replacement.

Fix 2: Adjust the Float (Free, 2 Minutes)

If water is running into the overflow tube, the float is set too high. The float tells the fill valve when to shut off by rising with the water level. When it reaches the correct height, it triggers the fill valve to close. If the float is set too high, the water level rises above the overflow tube and drains continuously into the bowl.

There are two types of floats, and each one adjusts differently. Identifying which type you have takes a quick look inside the tank.

Ball Float (Older Toilets)

A ball float is a round plastic or metal ball attached to the end of a horizontal metal rod. The rod connects to the fill valve at the top. To lower the water level, gently bend the float arm downward about half an inch. This causes the float to trigger the shutoff at a lower water level. Flush the toilet and observe where the water level stops. The target is about one inch below the top of the overflow tube.

If the ball has a crack or is partially filled with water, it will not float high enough to shut off the fill valve. In this case, replace the ball. Replacement balls cost $3 to $5 and screw onto the end of the float arm.

Cup Float (Newer Toilets)

A cup float is a small cylindrical cup that slides up and down the fill valve body. To adjust it, look for a metal spring clip or plastic adjustment screw on the side of the float. Pinch the clip and slide the cup downward about half an inch. For models with an adjustment screw, turn the screw counterclockwise to lower the float. Flush and check that the water level stops about one inch below the overflow tube.

Cup floats rarely fail on their own. If adjusting the cup float down does not stop the water from reaching the overflow tube, the fill valve itself is the problem and needs replacement. See Fix 3 below.

Fix 3: Replace the Fill Valve ($8 to $15, 15 to 30 Minutes)

If adjusting the float does not stop the running, the fill valve itself is worn out and needs replacement. The fill valve is the tall assembly on the left side of the tank that connects to the water supply line at the bottom. It controls all water flowing into the tank. Fill valves typically last 5 to 7 years, though hard water or high water pressure can shorten their lifespan.

What You Need

• Replacement fill valve ($8 to $15)
• Adjustable wrench or channel-lock pliers
• Bucket or container
• Towels or rags

Step-by-Step Instructions

1. Turn off the water supply. Close the shutoff valve behind the toilet by turning it clockwise.

2. Flush and drain the tank. Flush the toilet to remove most of the water. Use a sponge, towel, or wet/dry vacuum to remove remaining water from the bottom of the tank.

3. Disconnect the water supply line. Place a bucket or towels under the connection point at the bottom of the tank. Use an adjustable wrench to loosen the supply line nut where it connects to the bottom of the fill valve. Some water will drain out when you disconnect the line.

4. Remove the old fill valve. Inside the tank, disconnect the refill tube (the small flexible tube that runs from the fill valve to the overflow tube). From underneath the tank, unscrew the large plastic lock nut that holds the fill valve in place. Turn the nut counterclockwise. Once the nut is removed, lift the old fill valve straight up and out of the tank.

5. Adjust the height of the new fill valve. Most replacement fill valves are adjustable in height. Follow the manufacturer's instructions to set the valve height so that the top of the fill valve sits about one inch above the overflow tube. This ensures the refill tube can clip onto the overflow tube properly.

6. Install the new fill valve. Drop the new fill valve into the tank opening. The rubber washer on the bottom of the valve should seat firmly against the inside of the tank hole. From underneath, hand-tighten the lock nut. Then give it an additional quarter turn with the wrench. Do not overtighten; the plastic nut can crack.

7. Connect the refill tube. Clip the small refill tube onto the top of the overflow tube. This tube directs a small stream of water into the bowl during the fill cycle, which is necessary for maintaining the bowl water level and trap seal.

8. Reconnect the water supply line. Thread the supply line nut back onto the fill valve shank at the bottom of the tank. Hand-tighten, then give a quarter turn with the wrench. Again, do not overtighten.

9. Turn the water back on and test. Open the shutoff valve slowly. Watch for leaks at both connection points (supply line to fill valve, and fill valve lock nut). Let the tank fill completely. The fill valve should shut off when the water reaches the marked water line on the inside of the tank, roughly one inch below the overflow tube. Flush several times to confirm proper operation.

Which Fill Valve to Buy

The Fluidmaster 400A is the most widely used replacement fill valve in the United States. It fits nearly all standard toilets and costs $8 to $12. The Korky 528 is another reliable option in the same price range. Both are available at Home Depot, Lowe's, Ace Hardware, and most independent hardware stores. Universal fill valves work on the vast majority of toilet brands and models. Brand-specific fill valves are rarely necessary.

Fix 4: Replace the Flush Valve ($15 to $25, 30 to 60 Minutes)

The flush valve is the assembly at the bottom center of the tank that includes the overflow tube and the opening where the flapper seats. If the flush valve seat is cracked, corroded, or worn smooth, no flapper will seal properly against it. Replacing the flush valve is the most involved DIY toilet repair because it requires removing the entire tank from the bowl.

This repair is still well within DIY ability for most homeowners. It does not require specialized plumbing skills. However, it takes 30 to 60 minutes and involves lifting the tank, which weighs 25 to 40 pounds when empty.

What You Need

• Replacement flush valve assembly ($15 to $25)
• New tank-to-bowl gasket (usually included with flush valve)
• New tank bolts and washers (often included; buy separately if not)
• Adjustable wrench
• Channel-lock pliers or second wrench
• Bucket, towels, and sponge
• New flapper (usually included with flush valve)

Step-by-Step Instructions

1. Shut off water and drain the tank. Close the shutoff valve behind the toilet. Flush the toilet and hold the handle down to drain as much water as possible. Sponge out the remaining water.

2. Disconnect the water supply line. Use an adjustable wrench to remove the supply line nut from the bottom of the fill valve. Place a bucket underneath to catch residual water.

3. Remove the tank bolts. Underneath the tank, locate the two (sometimes three) bolts that secure the tank to the bowl. Hold the bolt head inside the tank with a screwdriver while using a wrench underneath to remove the nut. If the bolts are rusted or corroded, apply penetrating oil and wait 10 minutes. In extreme cases, the bolt heads may need to be cut off with a hacksaw.

4. Lift the tank off the bowl. Carefully lift the tank straight up off the bowl. It may be stuck to the old gasket. A gentle side-to-side rocking motion can break the seal. Set the tank upside down on a towel on the floor.

5. Remove the old flush valve. The flush valve is secured to the tank from outside by a large plastic lock nut (also called a spud nut). Unscrew this nut counterclockwise. Remove the old flush valve and the old tank-to-bowl gasket (the large rubber ring around the flush valve nut).

6. Install the new flush valve. Insert the new flush valve through the tank opening from inside the tank. The overflow tube should point straight up. From outside the tank, slide the new tank-to-bowl gasket over the threads, then hand-tighten the lock nut. Give the nut an additional quarter turn with pliers. The overflow tube height should be at least one inch below the top of the tank opening (where the lid sits) and at least one inch below the fill valve's critical level mark.

7. Reinstall the tank onto the bowl. Place the new rubber gasket (if separate from the lock nut gasket) over the flush valve nut. Set the tank back onto the bowl, aligning the bolt holes. Insert new tank bolts with rubber washers from inside the tank. Hand-tighten the nuts from underneath, then alternate between bolts, giving each a quarter turn at a time with the wrench. The goal is to tighten evenly so the tank sits level. Do not overtighten; the porcelain can crack.

8. Reconnect supply line and test. Reconnect the water supply line, install the new flapper, and turn on the water. Check for leaks at the tank-to-bowl connection, the supply line connection, and the flush valve gasket. Flush multiple times to confirm everything operates correctly.

If this repair feels too involved, a plumber typically charges $150 to $250 for a flush valve replacement. Given the labor involved, this is one of the repairs where professional help can be worthwhile, especially for homeowners who are uncomfortable lifting the tank. Learn more at our toilet repair cost guide.

When Should You Replace the Entire Toilet Instead?

In most cases, repairing a running toilet is more cost-effective than replacing the entire unit. A full set of internal tank parts (flapper, fill valve, flush valve, handle, and hardware) costs $25 to $50 and gives the toilet essentially new internals. However, there are situations where replacement makes more sense.

Replace if:

• The toilet is over 20 years old and needs multiple repairs. Older toilets develop recurring issues as all the internal components age simultaneously. Spending $100 to $200 on professional repairs for an aging toilet is often poor value when a quality new toilet costs $150 to $400.
• It uses 3.5 or more gallons per flush. Toilets manufactured before 1994 use 3.5 to 7 gallons per flush. Current federal standards require 1.28 to 1.6 gallons. Replacing a 3.5 GPF toilet with a 1.28 GPF model can save a family of four 10,000 to 20,000 gallons per year, easily offsetting the purchase price over time.
• The porcelain is cracked. Hairline cracks in the tank or bowl cannot be reliably repaired. A cracked tank can eventually fail catastrophically, flooding the bathroom. A cracked bowl creates a sanitation issue. Either requires replacement.
• The bowl does not flush well even with new parts. Some older designs simply do not flush efficiently. Modern toilets use improved bowl geometry, glazed trapways, and larger flush valves to provide a stronger flush with less water.
• Repair cost exceeds 50% of replacement cost. If a plumber quotes $200 or more for repairs and a quality new toilet can be installed for $300 to $500, replacement is the better investment.

Keep repairing if:

• The toilet is less than 15 years old and the issue is a single worn part.
• It is a high-quality brand (Kohler, TOTO, American Standard) that still functions well otherwise.
• The repair is a simple flapper or fill valve swap (under $15 in parts).
• The toilet is a specific color or style that would be difficult or expensive to match.

Parts Shopping Guide

Toilet repair parts are among the most standardized plumbing components available. Most homeowners can walk into any hardware store, buy a universal part, and have it work in their toilet. Here is what to know before shopping.

Universal vs. Brand-Specific Parts

Universal flappers, fill valves, and flush valves fit the vast majority of residential toilets. Brands like Fluidmaster and Korky dominate this category. A universal fill valve like the Fluidmaster 400A works in roughly 90% of toilets regardless of manufacturer. Universal flappers typically come with adapters that fit both 2-inch and 3-inch flush valves.

Some toilet brands use proprietary components, particularly for flappers and flush valve seals. Kohler, American Standard, and TOTO each have models that require brand-specific parts. If a universal flapper does not seal properly after installation, check your toilet model number (stamped inside the tank or behind the seat hinge area) and look for a matching brand-specific flapper. Brand-specific parts cost $8 to $15 compared to $3 to $8 for universal parts.

Where to Buy

Home Depot, Lowe's, and Ace Hardware carry the most common parts in-store. For brand-specific or less common parts, online retailers and manufacturer websites provide the widest selection. Amazon, PlumbingSupply.com, and manufacturer direct stores are good options for hard-to-find components.

Recommended Parts by Repair

Buying a complete tank rebuild kit ($20 to $30) is often the smartest approach if the toilet is more than 5 years old. These kits include a new fill valve, flapper, flush valve seal, tank bolts, and hardware. Replacing everything at once prevents future problems from other aging components.

Common Mistakes to Avoid

Most running toilet repairs are straightforward, but a few common mistakes can turn a simple fix into a frustrating experience. Avoiding these saves time and prevents repeat trips to the hardware store.

1. Buying the Wrong Flapper Size

Flappers come in 2-inch and 3-inch sizes. They are not interchangeable. A 2-inch flapper will not seal a 3-inch flush valve opening, and a 3-inch flapper will not fit on a 2-inch overflow tube. Before heading to the store, either bring the old flapper with you or measure the flush valve opening diameter at the bottom of the tank.

2. Overtightening Plastic Nuts

The lock nuts on fill valves and flush valves are made of plastic. Overtightening them with a wrench cracks the plastic, which means a trip back to the store for another part. Hand-tighten first, then give an additional quarter turn with a wrench. That is enough. If it leaks at the gasket, the issue is usually a misaligned washer, not insufficient tightening.

3. Forgetting to Adjust the Chain Length

A new flapper with the wrong chain length will either not seal (chain too short, holding the flapper open) or not flush properly (chain too long, not lifting the flapper high enough). Set the chain to about half an inch of slack when the flapper is seated.

4. Not Cleaning the Flush Valve Seat

If mineral deposits or corrosion have roughened the flush valve seat, a new flapper will not seal properly against it. Always wipe down the valve seat with a damp cloth or fine emery cloth before installing a new flapper. This step takes 30 seconds and prevents the most common reason a new flapper "does not work."

5. Skipping the Food Coloring Test After Repair

Always verify your repair by running the food coloring test after installation. Add 5 to 10 drops of food coloring to the tank, wait 15 minutes, and check the bowl. If no color appears, the repair was successful. If color does appear, the flapper may be the wrong size, the chain may be too short, or the flush valve seat may need attention.

6. Overtightening Tank Bolts

When reinstalling a tank after a flush valve replacement, alternate between the two tank bolts and tighten gradually. Overtightening one side before the other can crack the porcelain. Porcelain cracks are not repairable and require a full toilet replacement. Tighten until the tank is snug and level, then stop.

When to Call a Plumber Instead

Most running toilet repairs are well within DIY ability. But some situations call for a licensed plumber. Knowing the difference saves time and prevents potential water damage. For guidance on selecting a plumber, see our guide on how to find a good plumber.

Call a Plumber If:

• Water is leaking at the base of the toilet. Water pooling around the base of the toilet usually indicates a failed wax ring or a cracked bowl. A wax ring replacement requires removing the entire toilet, which involves disconnecting the supply line, removing tank bolts, lifting the toilet off the flange, scraping the old wax, installing a new ring, and resetting the toilet. While technically DIY-possible, it is messy and the toilet must be perfectly level on the flange to prevent future leaks. A plumber charges $150 to $300 for this repair.
• The porcelain is cracked. Cracks in the tank or bowl cannot be reliably repaired. Hairline cracks can expand over time, and a cracked tank can fail suddenly, releasing several gallons of water onto the bathroom floor in minutes. A plumber can assess the severity and install a replacement toilet.
• The problem persists after replacing the flapper and fill valve. If the toilet still runs after you have replaced the two most common failure points, the issue may be a cracked overflow tube, a warped flush valve seat, or a problem with the water supply pressure. A plumber has the diagnostic tools and experience to identify less common causes.
• The shutoff valve is stuck or broken. If you cannot turn off the water supply to the toilet, do not force the valve. Older gate valves can break internally if forced, causing a much larger problem. A plumber can replace the shutoff valve, which may require soldering or accessing pipes behind the wall.
• You see signs of long-term water damage. Warped flooring, soft or spongy subfloor around the toilet base, mold growth, or water stains on the ceiling below a second-floor bathroom all suggest a long-standing leak that may have caused structural damage. A plumber can assess the scope of the problem and recommend the right course of action.
• You are not comfortable with the repair. There is nothing wrong with calling a professional. A plumber can fix a running toilet in 15 to 30 minutes and the cost ($100 to $250) includes the diagnosis, parts, and warranty on the work. For more on what situations warrant calling a plumber, see our dedicated guide.

How Much Does Professional Toilet Repair Cost?

Professional toilet repair for a running toilet typically costs $100 to $250, which includes the service call fee, diagnosis, parts, and labor. The final cost depends on which part needs replacement and your geographic location. For a detailed breakdown, see our toilet repair cost guide. For general hourly rates, see plumber cost per hour.

Most of the professional cost is the service call fee, which typically ranges from $50 to $150 depending on the plumber and region. The actual parts for a running toilet repair are inexpensive ($3 to $25). This is why a running toilet is one of the best DIY plumbing repairs. The parts cost a fraction of the professional service call fee, and the work requires minimal tools and no plumbing experience.

Cost by Region

Plumbing labor rates vary significantly by region. The national average for a plumber's hourly rate is $75 to $150 per hour. Major metropolitan areas and high cost-of-living regions tend to be at the upper end. See our plumbing cost guide for a full regional breakdown.

• Southeast: 10% below national average
• Midwest: 5% below national average
• Southwest: 5% below national average
• Mountain West: Near national average
• Northeast: 15% above national average
• West Coast: 20% above national average

For city-specific pricing, see our local cost guides. For example, homeowners in the Cincinnati area can view our Cincinnati running toilet guide for local rates and plumber recommendations.

Plumber vs. Handyman

For a simple flapper or fill valve replacement, a handyman ($40 to $80) can handle the job. The repair does not require a plumbing license or specialized tools. However, a licensed plumber ($75 to $150) is the better choice if the flush valve needs replacing (involves removing the tank), if there is water on the floor (potential wax ring issue), if the problem persists after basic repairs, or if you suspect a larger plumbing issue beyond the running toilet.

A licensed plumber also typically provides a warranty on the work, usually 30 to 90 days. If the problem recurs during the warranty period, the plumber will return at no charge. A handyman may or may not offer this protection.

Tools and Supplies Checklist

Here is everything you might need for any running toilet repair. Most homeowners already have these tools. The only purchase is the replacement part itself.

Tools (Likely Already in Your Home)

• Adjustable wrench (for fill valve and supply line nuts)
• Channel-lock pliers (for flush valve lock nut and tank bolts)
• Flathead screwdriver (for holding tank bolt heads)
• Bucket or container (for catching water when disconnecting supply line)
• Towels or rags (for water cleanup)
• Sponge (for removing remaining water from the tank)

Supplies to Purchase

• Food coloring (for the diagnostic test, any color works)
• Replacement flapper ($3 to $8) or complete repair kit ($20 to $30)
• Replacement fill valve ($8 to $15), if needed
• Replacement flush valve ($15 to $25), if needed
• Fine emery cloth or ScotchBrite pad (for cleaning the valve seat, $2 to $4)

For most running toilets, the only purchase is a $3 to $8 flapper. Keep a spare flapper under the bathroom sink for next time. They take up almost no space and save a trip to the hardware store when the next one wears out.

Preventive Maintenance

A few simple habits can extend the life of your toilet's internal components and reduce the frequency of running toilet issues.

• Replace the flapper every 3 to 5 years. Do not wait for it to fail. A proactive replacement costs the same ($3 to $8) and prevents water waste. Homeowners with hard water or chlorinated water should replace every 2 to 3 years.
• Run the food coloring test once a year. It takes 15 minutes and catches silent leaks before they add up on your water bill.
• Do not use in-tank cleaning tablets. Drop-in bleach tablets and chemical cleaning products accelerate the deterioration of rubber flappers and valve seals. Use bowl-cleaning products instead, applied directly to the bowl rather than placed in the tank.
• Check the shutoff valve periodically. Turn the shutoff valve behind the toilet off and on once a year to prevent it from seizing. A stuck shutoff valve is a significant inconvenience during an emergency.
• Listen for running water. After each flush, briefly listen to confirm the fill valve shuts off. Catching a running toilet early prevents water waste and higher bills.

Frequently Asked Questions

For more plumbing cost information, visit our plumbing cost guide. For detailed toilet repair pricing, see our toilet repair cost guide. To diagnose other plumbing issues, try the plumbing diagnostic tool. For help finding a qualified plumber, read how to find a good plumber.