Toilet Bowl Water Level Adjustment: 6 Easy DIY Projects

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The water level in your toilet bowl and tank (especially when low) can impact the flushing power of your toilet.

And if you're not trying to save water, this might be a problem. Even when there's too much water, it also carries its consequences.

However, this is not a big issue as you can DIY adjust the amount of water in your toilet bowl without calling a plumber.

In this article, you'll know how much water in the tank is considered appropriate, why the level is low or high, and how to adjust the water level in your toilet bowl.

What Causes High or Low Water Level in Toilet Bowl?

If your toilet bowl water level is significantly lower (than half an inch of the overflow tube) or higher than usual, any of these may be the causes;

  1. Clogged toilet trap or drain (we'll treat this one last as it's responsible for high water level)
  2. Blocked toilet vent
  3. Worn out or unclipped refill tube
  4. Faulty toilet fill valve

Most times when the water inside your filled toilet bowl drains slowly, it indicates your toilet is clogged. And if the water level is always high, it shows there's something wrong with your toilet float.

So to fix the high water level, you're going to either unclog your toilet to prevent it from draining slowly or adjust the float.

How to Adjust Water Level in Toilet Bowl – Single and Dual Flush Toilet

5 Ways to Raise Low Water Level in Toilet Bowl

We'll first look at how you can raise the water level in your toilet bowl and tank.

Clear the blocked plumbing vents

Blocked plumbing vents mean air won't be allowed into your home's plumbing system. And these vents work to maintain the right pressure in the system to support the flow of water.

If your toilet gurgles or sputters when you flush other toilets or empty the bathtub in the house, it may be a sign of a blocked toilet vent. Here's how to fix your gurgling toilet.

To fix this, you'll have to climb to your roof and use your garden hose to flush your pipes. Quite easy, right?

But if this seems to be a recurring issue, you'll have to buy hardware that can cover the vents so leaves won't keep blocking the vents and affecting your toilet water level.

Adjusting the water level in a ball-and-arm float toilet

Most toilets use either the ball-and-float or the cylinder mechanisms, so we're going to look at a simple fix for both.

1. Remove the toilet tank lid

Raise the lid off of the tank and place it on a flat surface (would be nice to set it on the floor) to gain access to the flushing mechanisms.

2. Check the water level in the tank

When you check the tank, the water level in your toilet should be around an inch or two lower than the fill valve and overflow tube (the open pipe in the tank). Anything significantly lower or higher than this indicates a problem and means you'll have to adjust the water level to the desired height.

3. Turn off the water supply line to the toilet

Underneath your toilet wall is a knob-like external water valve that controls the water line to the toilet. Turn it off and flush the toilet. Now the tank is empty for you to work in it.

Don't try to repair the toilet tank mechanisms without emptying the toilet first. And don't worry, it won't refill if you closed the valve correctly.

4. Check if the float and fill valve is damaged

Check whether there are any defects with your float. If you notice any, you may need to call in a handyman to replace it.

If you don't find any problem with the float, we'll then check the toilet tank float's height.

5. Check the toilet tank float's height

The height of the floating ball indicates the tank water level inside the tank when it's filled with water.

If the float height seems higher or lower than the usual water level, this may be what's responsible for the low or high water level in your toilet.

To fix this, we'll adjust the toilet tank's float height.

6. Raise or lower the float height with a screwdriver

You'll find a screw at the top of the fill valve. You'll either have to turn the screw on your float clockwise to raise the water level in the tank or counterclockwise to reduce it. Do the screwing in one full rotation.

If the screw on the fill valve is too rusty, adjusting it with a screwdriver may be difficult. So you'll have to simply turn the float. And while turning the screw, be careful not to turn it more than one full rotation at a time to avoid the toilet flushing inconsistently.

Also, check if there's water in the floating ball by shaking it. If there is, you'll need to call in a plumber to fix it.

When you're done, it's time to test the water level to see if it's right.

7. Flush the toilet to test the water level.

We'll then turn the water line back on so we can fill the toilet tank again. Flush the toilet and check if the water level in the bowl is still too high or low.

And if the water level in your toilet is higher or less than midway full, repeat the process a couple more times till you're satisfied with the water level.

However, after adjusting the float without much progress, we'll try another approach.

But first, let's have a look at how to adjust the water level in a toilet bowl with cylinder mechanisms (also called a floating cup).

How to Adjust the Water Level in The Tank with Cylinder Float

If your toilet has got this type of float, you'll have no problem fixing it. It's easier to remove, fix, and install than the ball-and-arm float.

1. Lift off the toilet tank cover and check the water level

To gain access to the floating cup), we'll first take the tank lid out of the way. Ensure you drop it on a flat surface like your floor.

Then check the water level inside the tank to see if it's more or less than an inch or two below the fill valve or overflow tube. If it is, we'll have to adjust the water level.

2. Turn off the water supply line and flush the toilet

You'll find the external water valve underneath your toilet bowl. Turn the knob off, and flush the toilet to empty the tank.

3. Locate the adjustment stem and release clip

The adjustment stem is what's used to increase or decrease low or excess water inside the bowl. And it's not difficult to spot.

It's the long, slender tube that connects and runs parallel to the fill valve. Sometimes, the stem extends horizontally from the top.

And on the cylinder float, there's a release clip that you'll need to either raise or lower half an inch to adjust the float height accordingly.

4. Adjust the float half an inch

Once we've found our clip, we'll hold it tightly and twist the adjustment stem by turning it clockwise (to increase) or counterclockwise (to reduce).

If this doesn't work, we'll use a screwdriver to turn the adjustment screw clockwise or counterclockwise one full rotation on the screwdriver notch.

5. Turn the water line on and test the water level

We'll then replace the tank cover, turn on the water supply, and flush the toilet to observe the water level. There should be just enough water in the bowl.

But if the water in the bowl is still too much or too low, repeat the adjustment procedure a couple more times till you're satisfied. And if it still doesn't work, you'll have to either call a professional or install a replacement fill tube.

How to Install a New Fill Valve

If all else fails, changing the fill valve may be our last resort.

Tools you'll need;

  • Screwdriver
  • Replacement fill valve
  • Wrench or pliers
1. Turn off the water supply and drain the toilet bowl

Turn the knob under the toilet tank off, and flush your toilet. Ensure no water remains in the tank. But if there's residual water, absorb it with a piece of rag.

2. Remove the fill valve from the toilet tank

Usually, there are two nuts outside the tank; unscrew them.

You should first use your screwdriver to unscrew the nut that connects the hose carrying water to the valve; then pull the line out. If you're finding it difficult to unscrew the nut, use your wrench, or pair of pliers.

Afterward, unscrew the plastic nut holding the fill valve firmly to the tank; this should come off without much effort.

3. Take the old valve out of the tank

When you're done unscrewing the nuts, take the fill valve and float it out. But be careful not to damage or dislodge the other working parts in the tank.

You should have a hole at the base of the toilet tank now.

4. Slide the new valve into position

Insert the end of the valve into the hole at the tank's base and make sure to secure it in place. When it's well positioned, the other parts of the unit will stand in place.

5. Reattach the water hose

Now it's time to affix the water line. Connect the hose to the underside of the tank (where you took it out from) and screw both nuts tightly to prevent them from leaking.

6. Test flush your toilet

Turn the water supply back on and flush the toilet severally to see the new water level.

After testing the new level multiple times, you'll have to call in an expert plumber.

Unclog toilet without plunger

Cracked Toilet

While you might be yet thinking of calling a plumber to fix your low water level, the cause of the problem might have slipped right through our cracks.

It's possible that there might be a leakage somewhere that's causing the water in your toilet bowl to lower.

If you always find water puddles on the floor, it could indicate your toilet is leaking. Even if you don't find water on the floor, there could still be leakage as the leak could be below the floor.

It's advisable you quickly replace the whole toilet as leakages can lead to costly structural damage that'll be expensive to repair.

Simple Fix for High Water Level

Unclogging your Pipes

When you've got clogged pipes, water will find it difficult to flush out of your toilet. And this can make the water level in your tank to be higher than normal. Either water flows out slowly or the toilet bowl may even overflow if you continue flushing the toilet.

To be sure we're dealing with a high water level problem, we'll fill a bucket with water and pour it into the bowl. If the water doesn't flow out of the bowl, we can be sure there's a blockage somewhere.

Now, there are a couple of ways to fix this problem. Also, learn how to unclog your bathtub drain.

1. Check for large blockage in the toilet bowl with your hand

The first one is: to wear a pair of rubber gloves and dip your hand into the toilet bowl to search for items like diapers or the like that could be blocking the toilet.

If this doesn't bring out the blockage, we'll try to go a little deeper.

2. Thrust a plunger deep into your toilet or use chemicals

Use a plunger to go deeper into the toilet to bring out the blockage. And if this still doesn't work, pour a chemical product or hot boiling water into the toilet. These should do the magic.

However, if they don't work, you'll have to contact a plumber to come to have a look.


Final Thoughts on Toilet Bowl Water Level Adjustment

Adjusting the high or low water in the tank is not a difficult project that you should put off. It should take you around an hour to complete. So do it as soon as possible to avoid the situation deteriorating.

If you're going to install a new valve, make sure you reassemble each component in the right order. Also, remember to reassemble the small parts to avoid leaks.

And don't forget, the appropriate water level is one or half an inch under the overflow pipe.

Dino Paccino

Dino Paccino

Dino is a lifelong writer and home improvement specialist. He enjoys bringing cutting-edge information on home renovation and remodeling to Kitchen Infinity.

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