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A low water level in the toilet bowl results in weak flushes, no flushes, or odors rising from the sewer pipes. The most common reasons you’d have low water level in your toilet bowl are a detached or broken fill tube or a fill valve that’s adjusted too low.
Learn why you have a low water level in your toilet bowl and how to fix it without a plumber.
Detached or Broken Fill Tube
The fill tube in the toilet tank may be detached, broken, or incorrectly positioned. This prevents the water from reaching its correct fill height. Reattaching or fixing the fill tube is usually a simple fix.
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Attach or Replace the Fill Tube
Look for the thin, flexible plastic tube inside the toilet tank. It is usually black, and most of it will be above the water line. It should connect from the fill valve to the overflow tube. There are three quick fixes to try:
- Attach tube to refill valve: Fit the fill tube back over the nipple on the fill valve. If the tube is broken on the end, snip off about 1/2-inch with scissors.
- Attach tube to overflow tube: The other end of the fill tube should fit loosely into the open end of the overflow tube. Make sure that the end is inside the overflow tube.
- Replace the tube: If you can’t fix the fill tube, replace it. New toilet fill tubes cost about $6.
Fill Valve Adjusted Too Low
The fill valve inside the toilet tank has an adjustment screw. The screw may have gotten out of adjustment or it may not have been adjusted correctly in the first place. Adjusting or replacing the fill valve will reset the toilet bowl water level.
Adjust or Replace the Fill Valve
First, try to adjust the toilet fill valve. If that doesn’t work, replace the toilet fill valve.
- Adjust fill valve: Inside the toilet tank, alongside the fill valve, is another valve that controls the toilet bowl water level. Adjust this by hand or with a screwdriver. Imprints will show the direction to turn for more water in the bowl (+) and the direction for less water (-).
- Replace fill valve: A DIYer can replace a toilet fill valve with two channel-lock pliers. New fill valves cost $10 to $15. While it’s a simple project, you may feel more comfortable hiring a plumber for this project.
Toilet Leaks From Base
Toilet bowl water may leak from its base due to a poor seal. You may notice water leaking on the floor, especially if the toilet base is uncaulked.
If the toilet is caulked to the floor, the caulk may prevent water from leaking onto the bathroom floor. Instead, the water will leak through the floor, causing water stains in the ceiling below.
Reset the Toilet
Shut off the water supply, drain water from the toilet, and then remove the toilet.
Scrape off the old wax seal and thoroughly clean the metal toilet flange. Replace with a new wax seal or a silicone seal. Carefully set the toilet back in place and reattach it to the floor.
Clogged Rim Jets
The rim jets or inlet holes underneath the toilet bowl’s rim may be blocked. When you flush the toilet, the blocked jets prevent the full amount of water from flowing into the toilet bowl.
Clean the Rim Jets
To clean the rim jets, first clean the toilet with the toilet bowl brush. Then, warm up two cups of white vinegar and slowly pour it into the overflow tube in the toilet tank. Then flush the toilet.
Another method is to use a small hand mirror to look at the jets as you scrub them with a toothpick or a wire.
Cracked Toilet Bowl
Water may slowly leak through cracks in the toilet bowl. The leak may look like condensation on the outside of the bowl or as water pooling at the base, near the floor.
Repair or Replace the Toilet
In most cases, you will need to replace the toilet. You can fix a hairline crack in a toilet bowl with waterproof epoxy if the crack is located above the water line or isn’t holding back water.
Since the repair only costs $10 to $20, it’s often worth trying to see if it works before replacing the toilet.
Evaporation
The water level in the toilet bowl can lower due to evaporation. Water will evaporate when you are on a long vacation or during hot spells.
If too much water evaporates while you are gone, the water seal is no longer in place, and you will come home to a smelly home.
Prevent Evaporation
If you frequently travel for long periods, cap the toilet bowl with a toilet evaporation canopy. Canopies cost $10 to $15 and tightly fit the toilet rim.
Another solution is to wrap the top of the toilet bowl rim with plastic wrap. Leave a lower part in the middle of the wrap so that condensed water drips back into the bowl rather than along the rim.
Clogged Toilet
A clogged toilet can sometimes cause a low water level in the toilet bowl. Toilet clogs are usually associated with water overflowing.
However, a partial toilet clog may cause the level to drop. You’ll know this when you flush and the water level rises and immediately drops below the normal level.
Unclog the Toilet
You have several options for unclogging the toilet with traditional plumbing tools like a plunger or auger (a toilet snake). You can even unclog a toilet without a plunger.
- Use a plunger: Add water to the toilet bowl, tilt the toilet plunger sideways to fill it, and then firmly plunge. Be sure to use a toilet plunger (with a flange at the end), not a drain plunger.
- Use a toilet auger: Insert the hooked end of the toilet auger in the toilet, crank the handle, and pull back to remove the clog. Make sure you use a toilet auger, not a drain auger.
- Use dish soap: Dish soap can unclog a toilet by loosening waste stuck in the sewer pipe. Slowly pour a cup of dish soap into the toilet, let it settle for about 30 minutes, and then flush.
Broken Float Ball
The float ball inside the tank of older toilets should be buoyant. When it rests on the water, it controls the tank’s water flow. If the float ball is cracked or broken, it will be partially submerged and unable to do its job.
Replace the Float Ball
Damaged float balls usually cannot be repaired. The solution is to replace the float ball (also called a ballcock) assembly. This assembly includes the float ball and the fill valve, and it costs about $20.