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How to fix a toilet

Updated: Oct 28, 2022

Key Points:

  1. WikiHow is a pretty good source for small DIY project. Those small fixes are not complex and can be reliably used whenever there are issues.

  2. WikiHow has many similar articles about fixing a toilet, but we have picked the best article available for your convenience.

Everyday we need to use toilet frequently at home. It's very easy to have some issues with the toilet. Most of the issues are easy to deal with and can be fixed by DIY.

Here we quote the best way to fix a toilet provided by wikiHow, a wiki that is building the world's largest and highest quality how-to manual. Please edit the articles and find author credits at the original wikiHow articles on How to Fix a Toilet, How to Fix a Running Toilet, How to Fix a Slow Toilet. Content on wikiHow can be shared under a Creative Commons License.

Is there anything more terrifying than a toilet about to overflow? A creaking, burbling, malfunctioning monster of a commode is the fear of any homeowner. Fortunately, most common toilet problems can be easily and quickly fixed by diagnosing the correct problem and making a few simple adjustments.

Part 1: Fixing a Clogged Toilet

1. Shut the water off. If your toilet has become clogged, don't try to flush it or you'll risk overflowing the toilet. Find the water valve on the wall that connects the waterline to the toilet and turn it clockwise until it stops. Water should stop coming into the tank.

2. Get a plunger. It's called the plumber's helper for a reason. Some plungers have complicated bulb shapes and some are simple suction cups, but you just need to make sure your plunger is big enough to cover the opening at the bottom of the bowl. Make sure there's enough water in the bowl to cover the cup of the plunger. It's easier to have some water to force the clog out with, but now that you've shut off the water you can't flush anymore in from the tank. Get a few cups of water from the sink to add to the bowl if you need to.

3. Fix the suction cup onto the opening at the bottom of the bowl. Pump it forcefully and evenly. You should start to hear a gurgling in the pipe and feel some pressure building if you've created a suction with the plunger. After 5-10 pumps with the plunger, break the seal and see if the clog comes loose. If not, try again. If you can see the clog come up, you can try to flush the water down without turning the water back on. There should be enough water in the bowl to flush it. If the water all flushes down by itself after plunging, turn the water back on and let it run for a few minutes. When the water settles, try flushing it, but watch carefully and make sure it doesn't start to overflow. Shut off the water quickly if it does.

4. Use a plumber's auger or a "snake." If the clog is close to the top, the plunger should get it. If it has worked its way down the pipe, however, you might need the heavy artillery. A plumber's auger, also called a "snake," is essentially a long wire that you can reel out and guide through the pipe to forcefully dislodge the clog and then reel back up. Aim the tip of the auger into the bowl drain and reel it out. Be very careful not to force it and crank slowly and evenly. You don't want to bust a pipe fitting or get the auger stuck. When you've run the auger out, or feel that you've broken up the clog, reel it back in and try to plunge the toilet again or flush it and see if the clog has worked it's way through. If you don't want to buy an auger, you can fashion a simple device with a wire hanger to try to get at the clog.

Part 2: Fixing a Toilet that Runs Constantly

1. A running toilet can waste hundreds of gallons of water per day while racking up your water bill. This a problem you’ll want to address quickly! The best way to fix a running toilet is to start by inspecting the toilet flapper for issues. Toilet flapper issues are one of the most common causes of a running toilet. If the toilet flapper seems fine, try adjusting the water level of your toilet. Finally, if your toilet is still running, you’ll probably need to replace the toilet fill valve.

2. Things you should know: Check that you're flapper is working. Ensure that the chain is properly hooked to the flapper and that it's not worn and in need of replacement. Or, loosen the screw on top of the fill valve and adjust the float's height. Keep lowering the screw until the water is 1 inch (2.5 cm) below the overflow tube. Or, remove and replace your old fill valve. Connect your fill tube to the output nozzle and adjust the float as needed.

3. Addressing Flapper Problems.

Turn off the water and drain the toilet. Before you can check the flapper for problems, turn off the water to the toilet. Flush the toilet to drain excess water from the tank. This will allow you to inspect the flapper without having the toilet running constantly.

Remove the toilet tank lid and look inside. Lay down a towel somewhere safe and out of the way, such as in a corner. Hold either end of the lid firmly with both hands and pull the lid off the toilet. Place the lid on the towel to prevent it from getting scratched.

Adjust the chain length if necessary. The chain that pulls the flapper up can cause problems if it’s too long or too short. When the chain is too short, it will pull up on the valve when it shouldn’t, allowing water to drain constantly. When the chain is too long, it can get caught underneath the flapper and prevent a seal. If there's too much tension on the chain, remove the hook attaching the chain to the flush lever. Move the hook up 1 or 2 links until the chain has more slack. Reattach the hook to the flush lever. If the chain is so long that it can get caught under the valve, use a pair of wire cutters to trim a few links from the top of the chain. Reattach the hook to the new top link and reattach it to the flush lever.

Inspect the flapper for problems. Remove the flapper by unhooking the sides from the pins at the bottom of the overflow tube, which is the open tube in the center of the tank. Inspect the flapper for mineral deposits, warping, discoloration, disintegration, and other signs of trouble.

Clean a dirty flapper. Mineral deposits from the water can build up on the flapper and prevent it from sealing properly, allowing water to run. To clean the flapper, soak it in a bowl of vinegar for 30 minutes. After 30 minutes, scrub the rubber with an old toothbrush to dislodge buildup and dirt. Alternatively, put a few drops of baby shampoo on a rag and use it to wipe down the flapper. This will clean the flapper and add more elasticity to the rubber. When the flapper is clean, put it back in place. Attach the hooks on the side to the pins on the overflow tube. Turn the water back on and let the toilet tank fill. Listen for the sound of water running to see if that fixed the problem.

Replace a worn flapper. If the flapper is brittle and hard or doesn’t seal well after cleaning it, purchase a new one. Take the worn flapper to the hardware store and purchase a new flapper in the same style and with the same dimensions. You can also buy a universal flapper that will fit any kind of toilet.

4. Adjusting the Water Level.

Check the water level. When flapper trouble isn't the cause of a running toilet, the next most common cause is the water level. When the water level is too high, water will constantly drain into the overflow tube. Be sure to fix this problem as soon as possible to prevent water from spilling out onto the floor causing major water damage if the toilet gets clogged. With the water running and the tank full, look at the overflow tube. This is an open tube in the middle of the tank that connects the tank and the toilet bowl. Check to see if water keeps draining into the tube. If that’s happening, you can adjust the water level by lowering the float.

Determine the type of float you're dealing with. Water comes into a toilet tank via a fill valve. The fill valve has a float on it that rises or lowers with the water level. The float height is what tells the fill valve to shut off when the tank is full. Therefore, you can lower the water level in the tank by adjusting the height of the float. There are 2 main types of floats: A float ball fill valve will have a long arm attached to the fill valve, and at the end of the arm there will be a rubber ball-shaped float. Shake the float ball to determine if there is water inside it. If so, replace it. A float cup fill valve will have a small circular cylinder wrapped around the body of the fill valve. The cylinder, or float cup, slides up and down on the fill valve shaft, and its height determines the water level.

Lower the float on a float ball fill valve. On top of the fill valve, there will be a screw attaching the float arm to the fill valve. When you turn this screw, you can adjust the height of the float. With a screwdriver, turn the screw a quarter turn counterclockwise to lower the float. Flush the toilet and let the water in the tank refill. Check the water level. Ideally, the water level should be 1 to 1.5 inches (2.5 to 3.8 cm) below the top of the overflow tube. Continue adjusting the screw by quarter turns until the water level is right.

Lower the float on a float cup fill valve. The float on a float cup fill valve is adjusted in much the same way. There will be an adjustment screw on the top of the fill valve. When you turn this screw, it will adjust the height of the float. Turn the screw a quarter turn counterclockwise to lower the float. Flush and refill the toilet tank. Check the water level. Make another quarter-turn adjustment if necessary until the water level in the tank is 1 to 1.5 inches (2.5 to 3.8 cm) below the top of the overflow tube.

Check the fill tube if the toilet runs intermittently. The refill tube is a tube attached to the fill valve that fills the tank with water after it’s been flushed. This tube should always be above the water line, otherwise it can lead to intermittent running. When the tank is full, make sure the tube isn't in the water. To correct a fill tube that dips into the water, simply trim enough of the tube so that it sits above the water line.

5. Replacing the Fill Valve

Shut off the water and drain the tank. When fixing the flapper and adjusting the water level in the tank doesn’t fix a running toilet, it usually means there's a problem with the fill valve. The solution for this is replacing the fill valve. To do this, you must work with an empty tank: Turn off the water to the toilet. Flush the toilet. Use a sponge to absorb remaining water from the tank. Soak the sponge, wring it out in the sink, and continue until there's no water left in the tank.

Disconnect the water supply line. On the outside of the toilet, there will be a water supply line running into the tank. To disconnect this, unscrew the locknut securing the line in place. Turn the screw counterclockwise to loosen it. You may need a pair of pliers to loosen the locknut.

Remove the original fill valve. Once the supply line has been disconnected, you'll see a lock nut attaching the fill valve assembly to the toilet on the outside of the tank. Remove this by using an adjustable wrench to turn the lock nut to the left (counterclockwise). Once the lock nut is off, you can pull the old fill valve assembly out from the toilet tank. You may want to take the old assembly to the hardware store when you purchase the replacement. That way, you can be sure to get the right size and style fill valve for your toilet. Alternatively, you can purchase a universal fill valve. You can replace older ball float fill valves with more modern float cup style ones.

Install the new fill valve and connect the water. Insert the new fill valve into the same place in the tank. Fit the valve into the hole in the tank where the water supply line comes in. Hook up the water supply line. Tighten the nut in a clockwise direction to tighten it. Once the locknut has been hand tightened, use the pliers to turn the nut another quarter turn.

Attach the fill tube. Connect the fill tube to the water output nozzle at the top of the fill valve. Position the fill tube so it’s draining into the overflow tube. If there's a clip on the overflow tube, attach the fill tube to the clip to keep it in place.

Adjust the float. Check the manufacturer’s directions to determine the correct float height for the fill valve you purchased. Use a measuring tape to measure from the bottom of the tank, and adjust the fill valve to the right height by turning the adjustment screw.

Test the fill valve. Turn the water back on and let the toilet tank fill with water. Check the water level, make sure the fill tube isn't in the water, and listen that there isn't any water running. Adjust the float height if necessary. Test the toilet by flushing it and letting it fill up again. Once the toilet has been fixed and is no longer running, carefully place the tank lid back on.

Part 3: Fixing a Weak Flush (Slow Toilet)

1. Do you have a slow-flowing or flushing toilet? This can be caused by a variety of issues, though many of them can be fixed without calling a plumber. You’ll want to start by checking the tank, as this is the simplest cause. Otherwise, you may need to clean the toilet rim with household products. For toilets with serious deposits, you might even need to use muriatic, or hydrochloric acid.

2. Checking the Tank.

Find the source of the problem. "Slow toilet" can mean one of two things. Either the bowl isn’t filling quickly, or it isn’t draining quickly. If you’re dealing with the latter, the drain is likely clogged. You’ll need to unclog the toilet. If the bowl isn’t filling quickly enough, it could be an issue with the tank, like a low water level.

Lift the tank cover. The tank is the upright portion of the toilet, where you find the flushing handle. Lay the tank cover on the floor carefully; the heavy porcelain can potentially damage your floors.

Check the chain connecting the flushing handle to the flapper. The flapper is a piece of plastic or rubber which sits over the valve at the bottom of the tank. Unless your toilet isn’t flushing at all, there should be a chain connecting this to the trip lever, a small arm running from the flushing handle. The chain should have just enough slack for the flapper to rest over the valve, sealing it. But it should be tight enough to lift the flapper when the flushing handle is used. When you flush the toilet, the flapper should stay open for 2-3 seconds. Otherwise, the bowl won't be getting enough water.

Adjust the chain if needed. Performing this adjustment is rather simple. The chain should run through a hole in the flushing handle. You can easily disconnect the chain, and place a different link through the hole to adjust the chain’s overall length. The chain should be left with about half an inch of slack.

3. Using Dishwashing Soap and a Drain Cleaner

Pour a gallon of hot water into the toilet. Use a bucket to pour the water into the bowl. The hot water will help dislodge the residue that might be slowing the flow of water out of the bowl. Let the hot water sit in the toilet, don’t flush it. Warning, heating porcelain quickly or unevenly may crack the bowl.

Pour drain cleaner into the toilet. Make sure to use a product suitable for a toilet. The product you choose should have instructions detailing the amount you should be using. Make sure to read the label carefully. Some products aren’t meant for use on ceramics, and may require that you use protective equipment.

Put dishwashing liquid in the overflow pipe. You can find this upright pipe in the toilet’s tank. It will usually have a small tube running into it. You should put a small amount of dishwashing liquid in, only about a tablespoon. If you have a lime or calcium remover, like CLR, you can use that instead of liquid dish soap. It may be more effective.

Let the toilet sit for 10 minutes. This will give the dishwashing liquid time to seep down the overflow pipe. Additionally, the calcium and other deposits will slowly dislodge from the toilet’s walls, making for an easy clean.

Flush the toilet. This will send water through the tank’s pipes, and out through the holes below the toilet rim. The dishwashing liquid will dislodge any residue in the tank. The drain cleaner will remove any clogs or mineral deposits in the drain, improving the toilet’s flow.

Part 4: Replacing the Seat

1. Remove the old seat. One of the most common and easily fixable issues with a toilet is a broken or otherwise malfunctioning seat that needs replacing. First, you'll need to remove the old seat and dispose of it by removing the nut from the mounting bolts under the rim of the toilet and pulling the seat and lid off. Look under the lip of the toilet rim where the seat and lid connect to the bowl. You should see the nut and washer holding the seat on. Unscrew it with an adjustable crescent wrench and remove the washer and nut. The bolts should easily slide free from the top and you can remove the seat. If the nut is stuck or rusty, spray some WD-40 on it to help it come loose. Be careful not to struggle with the wrench too much and risk cracking the bowl of the toilet with your wrench or smacking your hand on something.

2. Get a new seat. Typically, most toilets are manufactured in two sizes, so make sure you've got the right size to match your particular toilet. Measure the width and length of bowl from the mounting bolt to the lip and take your measurements to the hardware or housewares store to make sure you've got the right size for your toilet.

3. Install the new seat. Fix the bolts through the holes in the toilet rim and screw the nut onto the bowl. Be careful not to use too much force when tightening, but make sure the seat is secure.

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