Fix a Running Toilet

A running toilet can waste hundreds of gallons of water per day, and cost you plenty of extra money on your water bill. Fixing a running toilet promptly will save you lots of money, water, and headaches. There are a few simple problems that can cause most toilets to run, and fixing them doesn’t require any special tools or knowledge. The key to fixing a running toilet is diagnosing the cause of the problem in the first place. Once you know the cause, you can proceed with fixing the issue.

Steps

Addressing Flapper Problems

  1. 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.
    • The flapper is a round rubber seal that stops water from draining from the tank and into the toilet bowl. When you flush the toilet, the chain pulls the flapper up so fresh water can fill the bowl.
    • Problems with the flapper are among the most common causes of a running toilet.
  2. 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.
    • Toilet lids are made of heavy ceramic, so don’t place them anywhere they can easily be knocked over.
  3. 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.[1]
    • If there's too much tension on the chain, remove the hook attaching the chain to the flush lever. Move the hook up one or two 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.
  4. 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.[2]
    • You can clean a dirty flapper that’s got mineral buildup on it.
    • A flapper that shows other wear-related problems should be replaced.
  5. 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.[1] 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.
    • 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.
  6. Replace a worn flapper. 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.[3]
    • To attach the new flapper, fit in into place and attach the hooks on the side to the pins on the overflow tube.
    • Turn the water back on and test the flapper to see that it’s functioning properly, and that the toilet isn't running.

Adjusting the Water Level

  1. 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.
    • 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.[4]
  2. 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 two main types of floats:[5]
    • 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.
    • 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.
  3. 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.[6]
    • 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.[4]
  4. 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.[4]
    • 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.
  5. 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.[3]

Replacing the Fill Valve

  1. 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:[2]
    • 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.
  2. 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.[7]
  3. 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.[8]
    • 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.[3]
    • You can replace older ball float fill valves with more modern float cup style ones.
  4. 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.
  5. 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.[9]
  6. 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.[9]
  7. 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.

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