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Toilet Bowl Water Level Recedes: Reasons and Solutions

When your toilet bowl water level recedes, finding the cause is fairly simple. However, whether you can repair it yourself or not depends on how brave you are with home repairs or how extensive the problem is. 

What causes toilet bowl water levels to recede (see our post on disappearing water for more information)? Sometimes the problem is with the floater or flapper. However, you might also have a leaking seal, cracked bowl, or even a clog in the vent pipe. Solutions include replacing parts, replacing the entire toilet, or unclogging the vent pipes. 

Toilet Bowl Water Level Recedes

Why Is My Toilet Bowl Water Level Receding?

Luckily, diagnosing toilet bowl problems isn’t rocket science (for example, if there’s blue stains in your bowl, read here for the solution). Most toilet bowl water level receding problems are inside the tank and are easy to see. There aren’t a lot of things to inspect inside a toilet tank. So, most of these problems will be fairly obvious.

Take the top off the tank and flush the toilet. You’ll want to inspect all the components inside the tank, the water level, and the seals. 

Don’t worry. The water in the tank is clean. Just get your hands in there to move the parts around until you discover what’s not quite right. If it really bothers you to think about putting your hands in the toilet, put on a pair of gloves. I won’t judge. 

Look for cracks, deterioration, and components that don’t quite fit as they should inside the tank. Check the water level. Then, inspect the seals outside the tank as well as the toilet bowl. 

Here are a few problems you might encounter if your toilet bowl water level recedes.

Broken Float

Since the float regulates the water level, I like to look at it first to ensure it’s not broken. 

The float looks different in different tanks. It will either be a cylinder that slides along a pipe to rise and fall with the water level. Or, it will be a bulb on a stick that rises and falls with the water level. Just flush the tank, and you will see it moving up when the water level rises.

Check to see if there are any cracks in the float. Water fills a cracked float and weighs it down. You’ve probably also noticed a constant sound of seeping water from your tank if the float is cracked.

Incorrect Water Level

You’ll also want to notice if the water is filling to the recommended water level. There should be a mark inside the tank to show the recommended level. If the water doesn’t fill to the recommended level, the floater level settings may be your problem.

Flapper Valve Seal Problems

The flapper valve is a rubber plug attached to a chain at the bottom of the tank. When you flush the toilet, you should see the flapper valve lift up. When it lifts up, all the water in the tank can fill the bowl below. 

Sometimes, the flapper valve can’t form a perfect seal. Without a perfect seal, the water leaks into the bowl when it shouldn’t and causes the water level to recede.

What should you look for? Inspect the flapper valve and seal. Notice if the flapper valve seal has shifted. Also, check for tears and cracks in the flapper or its seal.

Installing New Seal

Seal or Gasket Deterioration

You will notice several seals and gaskets in your toilet. As you can imagine, broken seals and gaskets cause unwanted leaks.

Seals and gaskets can become dried out, shrunken, or cracked. They obviously can’t do their job when they’re damaged. 

There are two main places you should check for damaged seals and gaskets:

  • Between the tank and bowl: A leak between the tank and bowl won’t provide enough water to the bowl.
  • Between the toilet and waste pipe: If the bolts that secure the toilet to the floor loosen and the toilet rocks when you use it, this wax seal can loosen.

Cracked Toilet Bowl

A cracked toilet bowl might sound obvious, but I’ve seen so many people miss a small crack. They just think the water on the floor is from other people in the house being careless with their toilet habits. 

If you dropped something heavy into the toilet or stood on your toilet, you could have caused it to crack. 

Some toilet bowl cracks are easy to see. However, you may not even notice hairline cracks without a close inspection. If you find a crack, read here for more information on fixing it.

Clogged Vent Pipe

If none of the possibilities above seems to be the problem, the issue is most likely deeper within your pipes.   

If you have a clogged vent pipe, you’ll notice the water recede in your toilet when another drain in your home is functioning. 

Does the receding water problem seem to come and go? If so, pay attention next time it recedes. Does the water recession problem coincide with someone using a sink or shower in the same room or elsewhere in the house? If so, you may have a clogged vent pipe.

How Can I Repair a Receding Toilet Bowl Water Level?

Some receding toilet bowl water level problems are easy fixes that you may be able to handle yourself (if you see little bubbles in your toilet bowl, read our guide here). Others are best left to a licensed plumber. Here’s a list of the best solutions.

Replacing a Broken Float

If the float has cracks, you will definitely need to replace it. It’s possible to replace a broken float yourself. 

You can buy a new toilet float kit at your local hardware store. Just realize that the kit is going to contain a new floater, flapper valve, and various small parts. So, you’ll essentially be replacing most of the innards of the tank. If overhauling your toilet seems overwhelming, there’s no shame in calling a plumber.

DIY Toilet Bowl Float Replacement “For Dummies” Tutorial [Toilet Float Replacement]

Adjusting the Water Level

Adjusting the water level in your tank is easy to fix. You only need a Phillips head screwdriver to do it. 

To adjust the water level, you will need to adjust the float. For most toilets, you only need to adjust the screw on top of the fill valve. Adjusting the screw controls how high the float can go, which controls the tank water level.

If you tighten the screw, the water level in the tank will be lower. If you loosen the screw, the water level in the tank will be higher. 

Adjusting the Water Level

Toilet Float System Repair : Toilet Repair

Repairing Flapper Valve Seal Problems

If the flapper valve has become misaligned, it’s an easy fix. Just shift the seal or flapper back into place and ensure it has a snug fit.  

However, if you notice tears or cracks in the flapper or seal, you’ll need to replace it. Luckily, you can buy a flapper valve separately to avoid replacing everything in the tank. 

How to Replace a Toilet Flapper Valve — by Home Repair Tutor 

Replacing Seal or Gaskets

If you’ve determined that your toilet is leaking between the tank and bowl or between the toilet and waste pipe, you will need new seals or gaskets.

If you’re thinking of doing seal or gasket repairs yourself, you should check municipal building codes in your area to find out if the job requires a licensed plumber. 

I like to recommend a licensed plumber anyway. I’ve seen too many people botch these jobs. They either end up with a worse leak, crack the tank or bowl, or make a mess with the wax sealant. 

Toilet Tank to Bowl Gasket Repair

Replacing Your Toilet

If your toilet has a big or hairline crack, I hate to tell you that it’s time to replace the whole thing. 

You may be surprised to find that new toilets aren’t terribly expensive. You can find the most simple ones at your local hardware store for around $100 or even less. 

There are two things to consider when you replace your toilet. Firstly, you will need to dispose of the old one. Secondly, you will need to determine if your municipality requires a licensed plumber to install your new toilet (read here to find out what kind of toilet plumbers recommend). If you’re lucky, the hardware store will provide haul-off and installation services. So, it’s worthwhile to call around town to find a store that will provide both.

If you’re brave enough to install the toilet yourself, good luck!

Unclogging the Vent Pipe

The average homeowner doesn’t have the equipment to unclog vent pipes. So, if you’ve noticed the water receding when another drain is in use, you’ll need to call a licensed plumber to locate the problem.

The plumber will have to go up on the roof to check where the clog is in the vent lines. A camera will show them the location of the clog so that they can work on unclogging the pipe.

How to Clear a Clogged Plumbing Vent | This Old House

The Bottom Line

When your toilet bowl water level recedes, it’s an indication that there is a problem that needs repair. Some fixes are easy ones that you can do yourself, while it’s best to leave others to a licensed plumber. Luckily, the problems are easy to diagnose so that you can get your water level problem under control quickly.

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