6 reasons why the water level in your toilet bowl is low
By Thumbtack Staff•Last updated Jan 29, 2024
Last updated Jan 29, 2024
Table of Contents
- 1. Your toilet’s fill tube is damaged.
- 2. Your toilet has a clogged sewer vent line.
- 3. Your toilet may have worn-out parts.
- 4. Your toilet could have a partial clog.
- 5. Your toilet could have insufficient water inside the tank.
- 6. Your toilet could have a crack.
- How do you raise the water level in a toilet bowl?
- Hire a plumber to fix your toilet problems.
- FAQs
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Are you experiencing a low water level in a toilet bowl? You may have a problem or some parts that need fixing or replacing. But where do you start?
Find out why your toilet's water level is low — and how to troubleshoot it.
1. Your toilet’s fill tube is damaged.
If you’re dealing with a weak or sluggish flush, the toilet’s fill tube may be kinked, damaged, or broken. A fill tube is a plastic hose that connects the water control and overflow tube, refilling the toilet bowl each time you flush.
How to fix: If it came loose, reattach it to the overflow pipe using the S-clip. If it’s damaged, you’ll need to replace it. You can do it yourself or hire a local professional.
2. Your toilet has a clogged sewer vent line.
If your toilet makes loud gurgling sounds, blows bubbles when you flush, or gives a weak flush, you could have a clogged sewer vent line. For proper flow, the vent must be open. If the vent pipe is blocked, the water flow creates a vacuum and slows the movement of waste. This can also clog your sewer line as waste flushes out of your toilet.
How to fix: You can try removing whatever is blocking the sewer vent pipe. Take a garden hose to the roof and run water down the vent pipe. This can force the obstruction down the sewer pipe and clear the vent.
However, you may want to hire a professional instead. Going up to the roof always involves a risk of falling and getting hurt.
3. Your toilet may have worn-out parts.
Most toilets have four main components that allow them to work. These parts may need repair or replacement if water levels are low.
How to fix:
- The toilet flapper. Pour some food coloring into the toilet tank water and check whether the water in the toilet bowl changes color. If it does, you need to replace the flapper.
- The flush valve. Fill the tank, then turn off the water supply at the shutoff valve. Mark the water level and let it sit overnight. If it drops to the bottom of the flush valve, you may need to replace the flush valve.
- The fill valve. Check whether water is going over the top of the overflow tube on the flush valve. If it hisses or drips continuously, some debris may be stuck inside. Clean the valve to see whether it works properly again.
- The trip lever. If you notice erratic flushing, the trip lever could be wearing out. You’ll need to replace it.
4. Your toilet could have a partial clog.
If your toilet water level is low, you could have a partial clog slowly siphoning water from your bowl.
How to fix: Use an auger with a bulb head to clear the clog. Check out this guide on how to unclog a toilet with or without a plunger. You may also want to read our guide on how to use a plumbing snake.
5. Your toilet could have insufficient water inside the tank.
Sometimes, a low toilet bowl water level is due to insufficient water inside your toilet tank.
Open the tank cover and check the water level once the fill valve shuts off. It should be about an inch below the overflow tube’s opening. If it’s lower than that, you may not have enough water to refill the bowl after you flush.
6. Your toilet could have a crack.
You may be seeing low toilet water levels because of a hairline crack in the bowl. Remove the toilet to look at the subfloor. If there is water, there’s a crack in the bowl.
How to fix: You’ll have to replace the toilet bowl. Talk to a plumber or a professional who specializes in plumber repair to get price quotes for a replacement.
How do you raise the water level in a toilet bowl?
If your toilet has a ball-and-arm float, you’ll need to turn a screw on the float valve clockwise to raise the water level. You may also bend the float arm to adjust the water level to where you want it.
If you have a cylinder float, you’ll need to press or squeeze the release to move the cylinder to where you want it. You may also have to rotate the adjustment dial instead.
Hire a plumber to fix your toilet problems.
While low water in a toilet bowl is nothing to be alarmed about, it can be annoying — especially if you can’t pinpoint the problem.
Stop stressing and hire a pro to troubleshoot your toilet issues. Download the Thumbtack app today to see a list of top-rated local plumbers. Get free cost estimates from a few of them, and schedule an appointment before they’re all booked up.
FAQs
How much water should be in the toilet bowl after flushing?
Toilet bowls are designed to hold a specific amount of water for optimum efficiency and flush. Water levels in your toilet bowl are determined by the piglet height of its internal P-trap. This may vary from one toilet bowl to another.
Consult your owner’s manual for more information.
Can I add water to my toilet tank?
Yes, you can add water to your toilet tank. Simply adjust the ball-and-arm float or cylinder float to accommodate more water.
How do I know if my toilet is losing water?
You need to look at and listen to your toilet. See whether a large leak causes moving water in your bowl even after your toilet tank has already been refilled. You can also try the food coloring test to see whether water flows out from the tank even if you’re not flushing.
Also, pay attention to how the toilet sounds after you flush it. It should only make a refill noise when the tank refills after the flush. If it makes any noise at any other time, you may have a leak or a problem with some parts of your toilet.
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