The toilet bowl usually remains nearly halfway full after flushing. Any low or high water level in the bowl after flushing indicates an underlying problem you should address.
So, why low water in the toilet bowl after flushing? Several issues can lead to low water in the bowl after flushing, including;
- Faulty fill valve
- Water supply issues
- Clogged toilet drain
- Cracks in the toilet bowl and base
- Faulty toilet flapper
However, a faulty fill valve is the most common reason for low water in the toilet bowl.
Keep reading to learn more about why your toilet may have low water in the bowl, how to fix these issues, and tips to keep the toilet in good working order.
Reasons For Low Water In Toilet Bowl After Flushing
Several issues can cause low water levels in the toilet bowl after flushing, including;
1. Toilet bowl crack
Toilet bowl cracks leak water from the bowl, slowly reducing the water level. You’ll usually find water on the floor if your toilet has cracks. Sometimes the crack happens near the toilet trap, so the water drips into it, making it unnoticeable, which means you need a plumber’s help.
2. Clogged drain
A clogged drain typically causes toilet bowl overflow but can also cause low water levels. In this case, a clog in the drain creates a partial obstruction causing a siphoning effect. This siphoning draws out water from the bowl until the level is low enough to break the siphon.
3. Faulty toilet flapper
The toilet flapper is a rubber stopper at the bottom of the tank that regulates water flow into the toilet bowl. A faulty toilet flapper will leak out the water leaving little behind, and when you flush, there won’t be enough to fill the toilet bowl properly.
4. Faulty fill valve
A fill valve controls how much water enters the tank after you flush. Hence, if it malfunctions, it won’t fill the tank appropriately, leading to low water levels in the toilet bowl after you flush.
5. Damaged refill tube
The refill tube controls how much water goes into the toilet bowl via the overflow tube. When this tube is damaged, the toilet bowl may overflow or have very little water.
6. Leaking at the base
The toilet bowl typically uses bolts that can get loose over time, causing the toilet to sway. This swaying can break the toilet base’s water-tight wax seal, causing the water in the bowl to leak out.
Sometimes the wax ring between the drain and toilet bowl also gets broken, causing water to leak from the toilet base.
7. Clogged rim jets
Rim jets are inlet holes that allow water from the toilet tank to pour into the bowl when you flush. Tap water contains calcium, so these holes calcify over time and get clogged. This clogging reduces the amount of water that pours into the toilet bowl.
8. Blocked toilet vent pipes
Toilet vents allow air to move through the toilet’s drain and facilitate the movement of wastewater through drain pipes. When the vent pipes are blocked, the water in the toilet bowl will be low after flushing, and you’ll hear gurgling sounds.
9. Water supply problems
If your house’s water supply has low pressure, water flow into the toilet tank will be affected, causing low water levels in the toilet bowl.
If your toilet has low water in the bowl, it can indicate many possible issues. Here are some steps you can take to pinpoint and fix the problem;
1. Inspect your home water supply
Ensure the water supply to the toilet is fully open. Open the toilet shut-off valve fully and let the toilet tank fill before flushing. That should fill up the toilet bowl to the correct level.
2. Inspect the toilet for cracks and leaks
Check the toilet for any signs of cracking in the toilet bowl, especially near the base. If you find or suspect your toilet has cracks, contact a plumber.
3. Check the fill valve
Open the toilet tank and inspect the fill valve. If the valve is not set to the correct water level, adjust its position. Though there are several types of fill valves, the process below will help you adjust yours.
Step 1: Turn off the water supply, remove the lid, and empty the tank
Step 2: Locate the fill valve (it’s usually found on the left side of the tank)
Step 3: Find the metal clip or screw on the float assembly
Step 4: Use a screwdriver or pinch the metal clip to adjust the height of the float accordingly
4. Inspect the refill tube
Identify the refill tube for signs of wear, blockage, or misalignment. To fix it, follow the guide below;
- If misaligned, reposition the refill tube’s holder clip or bend it to the correct position
- If blocked, use a thin stick or wire to clear the clog
However, if the refill tube is too worn out or cannot be unblocked, here’s how to replace it;
- Ensure the water supply is off, and the toilet tank is empty
- Identify the refill tube
- Loosen the clips and fittings connecting it to the fill valve and remove it carefully
- Attach your new refill tube and secure it with clips
- Turn on the water supply and test the new refill tube
- Adjust the height of the refill tube to ensure it allows the right amount of water in the toilet bowl
5. Check the flapper
Clean the flapper and check it for any signs of damage like tears, warps, or cracks. Here’s how to replace a flapper if it has any defects;
- Turn off the water supply and empty the toilet tank
- Locate the flapper – normally at the bottom of the tank
- Disconnect the flapper’s chain from the flush lever
- Remove the flapper by pulling it out of the pegs that hold it in place
- Attach the new flapper to the flush lever and pegs according to the manufacturer’s instructions
- Turn on the water supply and test your new flapper
6. Check the rim jets
Observe the rim jets for signs of clogging, and if you find any, use thin wires to clear the clogs.
7. Clear the toilet drain
It’s not advisable to pour hot water into a toilet bowl because it can cause cracks, so you must use other methods to unclog the drain.
- Use a plunger – Insert the plunger into the bowl, push it down firmly, and then pull it up quickly to create suction. Repeat this process a few times to remove the clog.
- Use toilet auger – If the plunger fails, use a toilet auger or drain snake. Insert the auger’s flexible end into the drain and push it in as you slowly rotate the handle until you feel it break through the clog. Flush the toilet to confirm the drain is clear.
- Use vinegar – Make a mixture of equal amounts of white vinegar and warm water, pour it into the toilet bowl, and let it sit for around 30 minutes before flushing the toilet.
8. Inspect the vent pipe
Climb onto the roof, check the vent pipe for any obstructions like debris or bird poop that may cause blockages, and clear them.
If the water in your toilet bowl remains low after following this troubleshooting guide, call a plumber.
Having low water in the toilet bowl can lead to some annoying problems, such as;
Clogging – Low water in the toilet bowl increases the chances of clogging.
Incomplete flushing – Toilet bowl water plays a vital role during flushing. So if the level is low, there may be insufficient water for proper flushing.
Stains – When water is too low, mineral deposits build up and dry to form tough stains in the bowl.
Foul odors – Toilet bowl water helps prevent sewer gasses from reaching the bathroom. So when the levels are low, some foul odors seep through the toilet and make it stink.
Here are a few tips you can use to keep your toilet in great condition;
- Avoid pouring hot water into your toilet if it’s made of porcelain because that will lead to cracking.
- Clean the toilet regularly to avoid clogging due to accumulated debris.
- Never use Drano to clear a clogged toilet because it can lead to corrosion.
- Avoid putting bleach tablets into toilet tanks because they damage rubber materials. Continual use of bleach tablets damages the tank’s rubber seals and causes leaks.
- Use alternative toilet paper types made from bamboo or hemp because they dissolve quickly, reducing the chances of clogging.
Here are some answers to common questions about toilets.
Yes, you can pour water into the toilet bowl to temporarily increase the water level. However, though this may solve the problem at that moment, it won’t resolve the underlying issues that continuously lead to low water in the bowl.
Problems that cause low water in the toilet bowl, such as blocked vents, water supply issues, and cracked bowls, can also completely dry out the bowl.
You shouldn’t increase the pressure of your toilet flush because it can damage the toilet. If the toilet has low flushing power, troubleshoot components like the fill valve, refill tube, and flush holes. However, if you realize the toilet may need more water pressure, contact a professional plumber for help.
The most common issues that cause low water in the toilet bowl include damaged refill tubes, faulty fill valves, clogged drains, cracked toilet bowls, and water supply issues.
Fortunately, you can fix most of these issues by yourself. For example, you can use plungers or vinegar to clear the toilet drain, unblock the vent pipe, and easily adjust the fill valve’s position. Always call the plumber if you find the issues hard to fix.