How to Adjust the Water Level in the Toilet

High or low water level in the toilet flush may not seem like a big deal, but over time it will. When there is not enough water in the tub, the flushing force will not be strong enough and cause the toilet to clog. Conversely, when there is too much water in the tub, the toilet may overflow or not flush completely. Fortunately, these problems are not difficult to solve. The height of the float can be easily adjusted by hand or screwdriver in minutes, and you do not need to hire a mechanic.

Table of Contents

Adjustment of float-arm mechanism

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Open the toilet lid. Lift the toilet lid off and set it aside. You now have access to the internal mechanisms of the toilet bowl. Take care not to drop the tub lid and do not place the lid in easy to drop places. The toilet lid is made of porcelain, so it is quite fragile.

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Notice the water level in the tub. The water level in the tank should be 2.5-5 cm lower than the supply valve and the anti-spill pipe (the large pipe is located near the center of the drain tank). If the water level is higher or lower than this, it is not in equilibrium. ^{[1] X Research Source}

Your toilet may have a marker on the inside of the sink, printed or engraved on the porcelain, indicating the water level to be set.

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Disconnect the water supply to the drain. Locate the water supply valve outside, on the back wall or under the toilet. Turn the knob all the way clockwise, then drain all the water in the tub. Once the water is drained, the tub will not supply water again. That way you can work inside the tub unobstructed. ^{[2] X Research Source}

Keep turning the knob until you hear the water stop flowing.
Do not attempt to adjust or repair anything in the toilet bowl that has not been drained first.

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Check float and supply valve. Observe the drain mechanism to assess its general condition. If you find any damage or defects, you may need to call a repairman. ^{[3] X Research Sources}

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Check the height of the float. Check out the float in the tub, which is a plastic ball that attaches to the swing arm on top of the water supply valve. The height of the float determines the amount of water in the tank after refilling. The float should be level with the marking line if it is in good working order. If the float seems too high or too low, adjust the height of the float and check the water level after the water refills.

If the float is above or below the mark, it may be the cause of too much/too little discharge.
Shake the float. If you hear the sound of water inside the float, have a mechanic replace it with a new one.
Make sure the float is properly connected to the supply valve.

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Use a screwdriver to adjust the height of the float. On the top of the supply valve there is a screw that attaches directly to it. Turn this screw one full turn clockwise or counterclockwise. Turning clockwise will raise the water level and counter-clockwise will lower the water level. ^{[4] X Research Sources}

Avoid turning the screw more than one turn at a time. Adjusting too much each time can cause the toilet to flush unevenly.
If the screw is too rusty and won’t turn, just rotate the float. The float is threaded to the lever arm that connects directly to the valve.

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Flush the toilet to check the water level. Turn the knob to open the water into the tub and wait 1-2 minutes for the water to fill. After flushing the toilet, you will observe the water level in the tub. Ideally, the water should be about half full. If the water level is still too high or too low, drain the tank and adjust the float again until the water level is satisfactory. ^{[5] X Research Sources}

Call a repairman if the water level is still not reached after several adjustments.

Cylindrical float adjustment

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Identify cylindrical floats. Some newer toilets are equipped with modern monolithic floats (sometimes called floating cups) instead of the float-arm design. This type of float is designed as a solid cylinder attached to the shaft of the supply valve. If the drain is equipped with a cylindrical float, you can adjust the water level in seconds.

Cylindrical buoys are easy to install, remove and maintain as well, friendly to users with little experience in home repair.

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Open the toilet lid. Open the tub cover and place it on a flat surface, such as a table top. Be careful not to drop the lid or place it near the edge of the table, as the sink lid is usually made of porcelain and can break easily. After opening the lid, you check the water level – if the water level is 2.5-5 cm higher or lower than the supply valve or anti-spill pipe, then you need to adjust.

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Turn off the water supply before you adjust the float. Locate the water supply valve outside, on the wall behind the toilet or under the sink. Turn the knob all the way clockwise. Once the valve is fully turned, drain the tub.

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Locate the adjustment lever on the side of the float. The regulator lever is a small and long tube, which connects to the supply valve. With most toilet models, it will run parallel to the valve or across from the top of the valve. The adjustment lever is used to increase or decrease the amount of water in the tub. ^{[6] X Research Sources}

You should learn the internals of the drain before making any major changes. Refer to the user manual or the manufacturer’s website if available.

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Find a clamp mounted on the float. Some cylindrical buoys are positioned by squeezing a clamp attached to the buoy to raise or lower the buoy to the desired height. Raise the lever to raise the water level and lower the lever to lower the water level. ^{[7] X Research Sources}

If the buoy is equipped with a clamp, squeeze the clamp to adjust the height of the float. If not, you have to find the position of the knob mounted on the lever.

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Raise or lower the float by more than 1 cm. Use 2 fingers to grasp the knob mounted on the top of the adjustment lever. Turn the lever clockwise or counterclockwise to raise or lower the float. After adjusting the float to the appropriate height, reinstall the tank cover and open the water to the tank.

If you cannot turn the adjustment lever, find a slot to turn the screwdriver. Some adjustment knobs are tightened with screws. ^{[8] X Research Sources}
Avoid turning the knob more than one turn at a time. If the water level is adjusted too high, the toilet may flush unevenly.

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Check the height of the water level after you open the water inlet valve to the tub. Flush the toilet a few times to see if the water level in the tub has decreased or increased. The water should be about half full. If not satisfactory, continue to adjust the float until the desired height is reached.

Call a repairman if the water level is not satisfactory after several adjustments.

Install new water supply valve

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Replace the water supply valve if the adjustment does not work. If the toilet flushes continuously and the float height adjustment is not effective, you need to replace the valve with a new one. Replacing a new valve requires opening a hole under the sink, if you are not used to doing relatively complicated things in the toilet, you should call a mechanic. ^{[9] X Research Source}

Depending on the type of toilet you will need a different type of valve. Go online to check the type of valve your model uses before you buy it.
You can also purchase a universal toilet repair kit at a hardware or hardware store. Including a new inlet, float and flush valve that fits in almost any toilet.

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Cut off the water supply and drain the water in the tub. To install a new water supply valve, you will need to empty the toilet bowl. Locate the water supply valve outside, on the back wall or under the toilet. Turn the knob all the way clockwise, then flush the toilet. Once the water is drained, the tub will not supply water again. Continue flushing until the tub is completely empty. ^{[10] X Research Source}

Use a sponge or towel to absorb any remaining water in the tub.

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Remove the supply valve from the outside of the toilet bowl. You will see 2 nuts on the outside of the toilet bowl. First, open the nut connecting the water supply hose to the valve. Pull the water supply hose out of the valve. Then, unscrew the plastic nut connecting the valve to the tank, usually you can open it easily by hand. After you have opened the two nuts, you can remove the supply valve from the tank. ^{[11] X Research Source}

You may need to use a wrench or pliers to remove the nuts.
Spread a towel to absorb the water seeping from the drain being removed.

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Remove the old valve from the tub. Pull the entire valve assembly out, including the float mounted on it. The valve set will be drawn in a single block. Throw away the old valve set unless you intend to have it repaired by a mechanic. ^{[12] X Research Source}

Handle with care to avoid damaging or dislodging other mechanisms inside the tub.

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Fit the new supply valve into position. Fit the base of the valve through the hole in the bottom of the tub. The rest of the valve set will stay upright after you’ve installed the valve, the valve should be tight and not wobble or move. Be sure to securely connect the valve to the bottom of the tub before reassembling the complete toilet. ^{[13] X Research Source}

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Reattach the water supply pipe. Attach the water supply hose to the base of the valve, and thread the washers that help connect the small water supply hose to the bottom of the toilet bowl. Tighten the plastic nut back to prevent leakage when you open the water supply.

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Turn on the water supply and try flushing the toilet. Find the water supply valve on the outside wall of the tank, turn the valve clockwise to open the water supply. Try flushing the toilet several times to check the new water level.

You should also check the shut-off valve and the footing of the new valve. Wipe the area clean to check for water leaks, and tighten connections if water leaks.
If the water level still does not reach, you should call a plumber. Plumbers can solve the problem easily.

Advice

If you need to replace a part, purchase a multi-function toilet repair kit at a hardware or hardware store. Including a new inlet, float and flush valve that fits almost any toilet model. This kit can help you with any water level problems, weak flushing, or constant flushing.
If you have trouble disassembling the toilet parts, you should call a repairman.

Warning

Don’t forget any small details when reinstalling the toilet. Forgetting to install something can cause water to leak or damage the structure over time.
When installing a new water supply valve, be sure to reassemble the components in the correct order.

Things you need

bake screwdriver
Towel
Dishwashing sponge
New water supply valve (optional)
Wrench or pliers (optional)

Steps