Home » Home Improvement & Repair » 6 Ways to Adjust Water Level in Toilet Bowl

6 Ways to Adjust Water Level in Toilet Bowl

Keeping the water in your toilet bowl at the correct level is crucial if you want your toilet to function correctly. If it is too high when you flush, it overflows, and if it’s too low it could struggle to remove solid waste effectively. 

We show you how to adjust the water level in your toilet bowl so that you can keep on top of any maintenance issues and keep your toilet working at optimum performance. 

Why Should I Adjust the Water Level?

Keeping the correct water level ensures there is enough water in the toilet tank to perform a flush effectively. It also keeps sewer odors at bay because the water forms a barrier over the sewer pipe. 

If the water level drops too low, you may suffer from smells drifting back through the pipes. Another reason why the water should be at a certain level is to stop unwanted critters and rodents from climbing up through your toilet. 

Sewer rats are capable swimmers, but they don’t like to be completely submerged, so the water in your toilet creates a barrier to discourage rats from entering your home. 

Too High vs. Too Low

So, what are the consequences of the water being too high or too low? Let’s find out.

Too High

  • The bowl will overfill.
  • It could be an indicator of a blockage. 
  • The float arm may need adjustment.
  • You risk flooding your bathroom floor.
  • The fill valve needs adjusting or replacing.

Too Low

  • Sewer odors can enter the home.
  • Sewer critters can climb through the toilet.
  • You may struggle to flush solid waste.
  • You may have a leak.
  • You may have a blockage.

Luckily, solving the problem of your water level is a simple task and usually doesn’t require a plumber. Here’s what you need to do if you notice your water levels are too high or low. 


Before we get into the how, when, and why, you need to gather some tools to get the job done effectively. You will need:

  • Pliers.
  • Adjustable wrench.
  • Wire coat hanger
  • Screwdriver.
  • Bowl.
  • Sponge.
  • Towel.
  • Epoxy resin
  • Toilet unblocking chemicals.

How to Adjust Water Level in a Toilet Bowl 

Unclogging Pipes

There is a strong possibility that when the water level in your toilet bowl is too high, clogged pipes are on the list of usual suspects. 

You can spot this problem when you flush the toilet and the water fails to drain away. The water might drop slowly if you leave it, but mostly it will sit in the bowl, which means there is a blockage. 

If you don’t deal with the issue, the water will eventually spill over the top and flood your floor every time you flush. 

A great way to test if the water drains slowly is to fill a bowl with water and pour it down the toilet. If the water doesn’t drain, you may need to pull on a pair of gloves and start delving into the pipes to feel for blockages. 

If the clog is further down the pipe, try using a plunger, and if that doesn’t work, use a chemical solution that unclogs toilets. The downside with this is chemical solutions are terrible for the environment. 

You could also grab a wire coat hanger and untwist it, so it forms a long wire. Push it down into the pipes, working back and forth. If you feel it move deeper into the pipe, there is a chance you are clearing the blockage.

If the water suddenly starts to drain away, success! You’ve done it.

Clear the Plumbing Vents

Your toilet relies on a careful balance of pressure, so if the plumbing vents are blocked, you might notice a drop in toilet performance. 

When the vents become blocked, air cannot enter the system, and the water doesn’t flow properly. One of the biggest signs that this is an issue is hearing your toilet start to bubble and gurgle. 

If you are brave enough to climb onto your roof, grab a garden hose and flush out your pipes. It could also be something as simple as fallen leaves blocking the vent, so you might want to invest in a cover to keep the vent free from debris. 

Look For a Crack in the Toilet

Sometimes it may not seem that obvious why your water levels are fluctuating, so it might be time to look for hairline cracks in the toilet bowl. 

One of the biggest giveaways is when you find puddles of water at the base of the toilet. One of the worst things you could do is ignore this because it will lead to flooding and your floor rotting. 

If you find a hairline crack, get it sorted straight away. The best advice is to replace the toilet, but you can fill the gap with epoxy resin as a short-term fix. It is waterproof, hardwearing, and seals rock hard. 

Adjusting a Ball-and-Arm Float

Lift the toilet tank lid and grab the screwdriver. Place the lid to one side, laying it carefully on a dry towel. The ball float connects to the water fill valve, and it is here that you will find the adjusting screw. 

Turn it clockwise to lower the ball and counterclockwise to raise it. This then raises or lowers the water level. The correct level for the water should be about an inch below the overflow tube.

Adjusting a Cylinder Float

Cylinder float valves are super quiet compared to traditional ball floats. It has an internal float lever inside the head of the valve, and it operates in the same way as a float-cup valve, only much quieter. 

To adjust it, simply twist the top head of the valve counterclockwise to remove it. Move the fill valve up to raise the water level and down to lower it. When you have the desired height, screw the valve head back on.

Installing a New Fill Valve

Installing a new fill valve is slightly more involved. You need to drain the water tank, so locate the water tap isolator just below the water tank and turn the knob until the water is shut off. 

Flush the toilet to drain the water out of the tank. Do this a couple of times until there is only a shallow pool at the bottom. Grab the sponge and the bowl and mop it dry. 

Detach the fill tube and twist the fill valve locking nut, and loosen. If it needs extra persuasion, grab the pliers or adjustable wrench. Now remove the nut and lift the fill valve out of the tank. 

Grab the new fill valve and insert it into position, making sure that the top is 1-inch above the overflow.

Push down on the valve and tighten the locking nut either by hand or using the tools. Then reattach the fill tube and then turn the water back on and allow the water to flow back into the tank. 

Adjust the water level by squeezing the adjustment clip and moving the float up or down. Some models have an adjustable screw located next to the float. 

It’s Easier Than You Think

The next time your toilet water levels change, do a bit of investigating. It’s a simple process of elimination to determine what the route cause could be. But rest assured that almost 99 percent of the time, you can fix it yourself with the minimum amount of fuss and time. 

So, the next time you come up against a problem, don’t reach for the phone to call a plumber, reach for the pliers and roll your sleeves up.