How to Adjust Toilet Bowl Water Levels (Ball-and-Arm or Cylinder Floats)

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Pro plumbers share how to change your water level & why it matters
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A high or low water level in your toilet may not seem like a big deal, but with time, it can cause problems. When there isn’t enough water in the tank, the flushing power may suffer, leading to troublesome blocks and clogs. When there's too much water in your toilet bowl, though, your toilet may not flush all the way or overflow. Luckily, neither of these issues is too difficult to solve. In this article, we work with professional plumbers David Balkan and James Schuelke to teach you how to solve those issues and adjust your water level in just a few minutes. Keep scrolling to learn more!

Changing a Toilet Bowl’s Water Level: Overview

Remove the toilet tank lid and note the water level. It should rest 1–2 inches (2.5–5.1 cm) below the fill valve. To change, turn off the water supply and flush to drain the tank. For ball-and-arm floats, turn the screw on the fill valve to adjust the water level (turn clockwise to raise and counterclockwise to lower).

Section 1 of 6:

Adjusting a Ball-and-Arm Float

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  1. Lift the lid off the tank and set it aside on a flat, stable surface (be careful not to drop the lid or set it somewhere from which it might fall and break). Check the water level by looking at where it sits in the tank. The water in the tank should rest 1–2 inches (2.5–5.1 cm) below the fill valve and overflow tube (the large open pipe near the center of the tank). If it seems higher or lower than this level, your water level may be off-balance. [1]
    • Your toilet may also have a line in its tank, either printed on or etched in porcelain, that shows you where the water level should be.

    Meet the wikiHow Experts

    David Balkan is a professional plumber of over 40 years, with specialization in water service lines, sewers, and drain line issues.

    James Schuelke is a professional plumber specializing in leak detection and mold inspection. He has over 32 years of experience and owns plumbing companies in Phoenix, Arizona, and the Pacific Northwest.

  2. Locate the external water valve on the wall behind and beneath the toilet. Rotate the oblong knob clockwise as far as it will go to turn off the water supply , then flush the toilet. After it flushes, the tank will not refill itself. This will allow you to work inside the tank unobstructed. [2]
    • Pro tip: Schuelke says to always go a quarter turn more after turning the water off to ensure that it’s completely off. [3] Keep turning the knob until you hear the water stop running.
    • Do not attempt to adjust or repair any of the mechanisms inside the toilet tank without emptying it first.
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  3. Check the toilet tank’s float, a plastic ball attached to a long arm at the top of the fill valve. The height of the float determines how much water remains in the tank after it refills. It should be at the water level if it is not broken. If the float appears too high or low, adjust the float height, and when you refill the tank, check how it changes the water level. [4]
    • If it is above or below the water level, this may be the source of your high/low water level.
    • Inspect the float and fill valve for damage while you do this. If you notice any obvious damage or defects, you might need to call a professional to have the part repaired.
    • Give the float a shake. If you can hear water inside of it, you should have a plumber replace it.
    • Make sure the float is properly connected to the fill valve.
  4. Directly on top of the fill valve should be a single screw. Turn this screw clockwise or counterclockwise 1 full rotation to adjust the fill valve . Clockwise will raise the water level, and counterclockwise will lower it. [5]
    • Avoid turning the screw more than 1 full rotation at a time. Doing too large of an adjustment at once could cause the toilet to flush inconsistently.
    • If the screw is too rusty to turn, you can adjust the float by simply turning it. It is threaded to the metal rod that connects directly to the fill valve.
  5. Turn the water to the toilet back on and give the tank a minute or 2 to fill up. After you’ve flushed the toilet, observe the water level in the bowl. Ideally, the bowl should be about halfway full. If the water in the bowl still looks too high or low, empty the tank and try adjusting the float again until you get it right. [6]
    • Call a plumber if the water level is still off after adjusting the float several times.
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Section 2 of 6:

Adjusting a Cylinder Float

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  1. Remove the lid from the tank and set it aside on a flat surface. After the toilet lid is removed, locate the external water valve on the wall and rotate it clockwise as far as it can go to turn off the water supply. Then, check the water level—if it seems higher or lower than 1–2 inches (2.5–5.1 cm) below the fill valve and overflow tube, it may need adjustments. [7]
    • Be careful not to drop the lid or set it near the edge of a surface, as most toilet lids are ceramic and break easily.
  2. Some newer toilets are equipped with one-piece floats (also sometimes known as “floating cups”) instead of the older ball-and-arm design. [8] These types of floats are engineered as solid cylinders fitted to the shaft of the fill valve itself. If you have a fill valve with a cylinder float, you can adjust the water level in your toilet in just a few seconds.
    • Cylinder valves are easy to install, remove, and perform maintenance on, and are more user-friendly for individuals less experienced with home repairs.
  3. The adjustment stem is a long, slender tube that connects to the larger fill valve. In most models, it will either run parallel with the valve or extend horizontally out from the top. The adjustment stem is used to increase or decrease the amount of water in the tank. [9]
    • Familiarize yourself with the mechanisms inside your toilet tank before making any drastic changes. Refer to the instruction manual or the manufacturer's website if available.
  4. Some cylinder floats can be positioned by squeezing a release clip on the float itself and raising or lowering it to the desired height. Raising the dial will raise the water level, and lowering it should lower the water level. [10]
    • If your float has a release clip, squeeze it to adjust it to the desired height. If not, however, you will need to locate the toilet's adjustment dial.
  5. Use 2 fingers to grasp the notched dial on the end of the stem. Twist the stem clockwise or counterclockwise a full rotation—clockwise to lower the height or counterclockwise to raise it. [11] Once you’ve found a suitable height for the float, replace the toilet lid and turn the water valve back on.
    • If you’re having trouble turning the adjustment stem, check for a screwdriver notch. Some adjustment dials are secured by screws. [12]
    • Do not turn the notch more than 1 full rotation at a time. If your toilet water level is adjusted too suddenly, it can cause inconsistent flushing.
  6. Flush the toilet a couple of times to check whether the water level in the bowl has lowered or risen. The bowl should be about halfway full. If not, continue fine-tuning the float until you reach your desired height. [13]
    • Call a plumber if, after several adjustments, the level still seems off.
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Section 3 of 6:

Installing a New Fill Valve

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  1. If your toilet runs constantly and changing the float's height doesn't help, you may need to replace the fill valve . Replacing a fill valve involves opening the hole at the base of the tank—if you do not feel comfortable working this extensively with your toilet, you may need to call a plumber. [14]
    • The fill valve you need may vary depending on the kind of toilet you have. Check what kind of fill valve your toilet model needs online before buying one.
    • You can also buy a universal toilet repair kit at a hardware or department store. It comes with a new fill valve, float, and flapper that fit almost every toilet.
  2. To install the replacement valve, the toilet tank needs to be completely empty. Locate the external water valve on the wall behind and beneath the toilet. Rotate the knob clockwise until it will not go any further, then flush the toilet. After it flushes, the tank won't refill itself. Continue flushing the tank until the water is completely emptied. [15]
    • Sop up any residual water in the tank with a sponge or towel.
  3. You should see 2 nuts on the outside of the tank. First, unscrew the one that connects the water supply line to the valve. Pull the supply line out of the valve. Then, unscrew the plastic nut that secures the fill valve to the tank, which should be easy to loosen. With both nuts unscrewed, the fill valve should come right out. [16]
    • You may need to use a wrench or pair of pliers to loosen the nut.
    • Lay down a towel in case any residual water leaks out of the detached water supply hose.
  4. Extract the entire fill valve unit, including the attached float. The unit should simply come out in 1 piece. Discard the old valve unless you plan to have it repaired by a professional later. [17]
    • Work carefully to avoid damaging or dislodging any of the other mechanisms inside the tank.
  5. Fit the bottom portion of the valve through the hole in the base of the tank. The rest of the unit should sit upright once the fill valve is in place, and it should feel secure—no wobbling or moving around. Make sure it's attached to the base before putting the toilet back together. [18]
  6. Attach the hose back to the bottom of the valve, and slide back on any washers connecting the small water supply hose to the base of the toilet tank. Screw the large nut back on tightly to prevent leakages when you turn the water supply on again. [19]
  7. Locate the external water valve again on the wall behind the toilet and rotate it clockwise to turn on the water supply. Flush the toilet several times to test the water and check its new level. [20]
    • You should also check the water shut-off valve and the bottom of the new fill valve. Wipe these areas with a tissue to check for moisture, and tighten the connections again if you find any.
    • If the level still seems off, call a professional. A plumber may be able to troubleshoot your problem and solve the issue.
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Section 4 of 6:

Causes of Water Level Issues

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  1. Clogs, calcification, or a low water supply could impact your water level. Water levels are supposed to be consistent in toilets. Although the level varies depending on the manufacturer, unusual fluctuations in how high or low your water is can indicate a more serious issue that needs to be addressed. According to Schuelke, there are three reasons why a toilet may flush slowly, possibly indicating water level issues: [21]
    • Soft stoppage: An obstruction stops toilet paper and debris from going through the P-trap, leading to a slow flush and a change in water levels.
    • Calcified rim: The rim that regulates the amount of water going into the bowl is calcified, restricting the amount of water that goes into the bowl.
    • Low water in the tank: The level of water must be at the highest setting. If not, the flush will be weaker. Lower levels of water in the bowl can also cause sewage smells to penetrate the bathroom.
Section 5 of 6:

Maintaining Your Toilet’s Water Level

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  1. 1
    Check for leaks regularly. Observe the outer rims of your toilet for leaks. Look behind the toilet, where the toilet connects to the ground, and at any other potential external leak locations. To check for leaks inside the toilet, get a toilet leak detection kit , drop a dye tablet from the kit into the tank, wait 15 minutes, then check the toilet bowl. If there’s dye in the bowl, there’s a leak in the toilet. [22]
  2. 2
    Check the water levels in the tank regularly. Whether you’re starting to notice issues with your water level or are eager to prevent them, check the water levels in your tank weekly to ensure that they’re about 1 inch (2.5 cm) below the manufacturer’s fill line. Remove the tank lid and find the line on the side of the tank to check.
  3. 3
    Remove clogs with a plunger and regularly flush to prevent build-up. When the toilet starts to fill up while you’re still doing your business, flush to prevent overflowing. If you flush and it starts to clog or overflow, grab a plunger, put it into the toilet over the bowl, and pump until the water drains and the flush is completed . Once the toilet flushes after plunging, the water level should return to normal. [24]
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Section 6 of 6:

Why is the water level in a toilet important?

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  1. Your toilet is designed to function properly with a specific amount of water. Toilets work by sending water from the tank into the bowl, triggering the fill valve once the tank empties, and refilling the tank and bowl. [25] If the water is too low, it can weaken flushing pressure, cause clogs, and lead to a buildup of waste in the trap or drain. If it’s too high, it can cause overflowing, an overwhelmed toilet system, and higher water bills. So, it’s important to maintain optimal levels.

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      Tips

      • If you feel uncomfortable dismantling and reassembling your toilet, the safest bet is to call a plumber.
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      • If you need to replace different parts, buy a universal toilet repair kit at a hardware or department store. It comes with a new fill valve, float, and flapper that fit almost every standard toilet, and only costs $10-$20. A kit can help you fix most problems with water level, poor flushing, and continuous running.
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      Warnings

      • When installing a new fill valve, reassemble each component in the correct order.
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      • Don’t forget any small pieces while reassembling your toilet! Missing pieces can cause leaking or structural damage over time.
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      References

      1. ↑ https://homesteady.com/how-12113700-adjust-antisiphon-fill-valves.html
      2. ↑ https://youtu.be/VIuC4UVXgBQ?si=AweynZjPuUrEiTt_&t=10
      3. ↑ James Schuelke. Professional Plumber. Expert Interview
      4. ↑ https://youtu.be/99oj-NPYrEo?si=0rr68tBBDHcOmsTH&t=14
      5. ↑ https://youtu.be/99oj-NPYrEo?si=0YNqguB1YuPHugQI&t=19
      6. ↑ https://www.home-repair-central.com/how-to-adjust-a-toilet-float.html
      7. ↑ https://youtu.be/VIuC4UVXgBQ?si=AweynZjPuUrEiTt_&t=10
      8. ↑ https://youtu.be/TC3xyrOrN-c?si=L_QxG4HiBPf7suEK&t=27
      9. ↑ https://www.home-repair-central.com/how-to-adjust-a-toilet-float.html
      1. ↑ https://youtu.be/VIuC4UVXgBQ?si=lUIXCqllQIsJbq_8&t=50
      2. ↑ https://youtu.be/TC3xyrOrN-c?si=ZLu1d1l4JQlSywOm&t=117
      3. ↑ https://www.home-repair-central.com/how-to-adjust-a-toilet-float.html
      4. ↑ https://youtu.be/TC3xyrOrN-c?si=M2EIy2MO-v8RrKR5&t=130
      5. ↑ https://www.home-repair-central.com/adjusting-the-toilet-tank-water-levels.html
      6. ↑ https://youtu.be/UhVpipC0BEw?si=0_8F2fYHG-hrlIQ3&t=149
      7. ↑ https://youtu.be/UhVpipC0BEw?si=y1-yREGOb69V5M4q&t=165
      8. ↑ https://youtu.be/UhVpipC0BEw?si=nkm1Im2ewuP2CNhY&t=174
      9. ↑ https://youtu.be/UhVpipC0BEw?si=7AM_XnMeEw6TEiBp&t=197
      10. ↑ https://youtu.be/UhVpipC0BEw?si=SszD3mDLBbHWt-kg&t=209
      11. ↑ https://youtu.be/UhVpipC0BEw?si=LFxTCY-aCXTNN4ho&t=216
      12. ↑ James Schuelke. Professional Plumber. Expert Interview
      13. ↑ https://www.portland.gov/water/water-efficiency-programs/fixatoiletleak
      14. ↑ David Balkan. Professional Plumber & CEO of Balkan Sewer & Water Main. Expert Interview
      15. ↑ https://live-wp-sa-housing-1.pantheon.berkeley.edu/living-on-campus/cleaning-maintenance/
      16. ↑ https://wpplumbing.com.au/blog/how-toilets-work

      About This Article

      Article Summary X

      To adjust the water level in your toilet bowl, start by removing the tank lid and noting if the water level looks too high or low. Then, turn off the water supply to the toilet by rotating the knob on the wall behind the toilet clockwise as far as it will go. Once the water is off, check the float, which is a plastic ball attached to a long arm at the top of the fill valve. Since the height of the float determines the water level, turn the screw on top of the fill valve 1 full rotation clockwise to raise the water or counterclockwise to lower it. After you adjust the float, turn the water back on and flush your toilet to see if you fixed the issue. To learn how to adjust a cylinder float to fix the water level in your toilet, keep reading!

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