Finding the root cause of a weak flushing toilet is the first step in fixing it. The solution to a weak or incomplete flush is often simple once you have identified the cause.
Below are the 8 most common reasons for why you might be experiencing a weak flush and our easy solutions on how you can to fix it.
1) Clogged waste pipe
A toilet waste pipe’s purpose is to drain waste and water from your toilet bowl and into the drain outside your house. You will immediately know if the waste pipe is blocked since the water in the toilet bowl will not have any place to escape when flushed. You might have just a partial blockage if you have both a slow drain and weak flush.
No matter how clogged the waste pipe may be, the steps for fixing it are the exact same.
Solution: Plunger or plumbing snake
Use a plunger to start. The plunger works by pushing water back and forth through the waste pipes, breaking down any debris. A plunger with a flange extension is the best type for unclogging a toilet. The flange makes every plunge more efficient and fits better. A plunger shaped like a bell with no flange extension may work for your toilet; however, it is designed to be used on shower drains.
A plumbing snake is a great option if plunging does not work. Plumbing snakes are designed to remove clogs beyond the toilet. The long, coiling cables can be inserted into the waste pipe to extract the debris.
2) Clogged jet flush hole (Siphon Jet)
The jet flush hole (also known as the siphon jet) is a small compartment at the front of the toilet. It holds water and then releases it at an angle so that waste can be pushed directly into the trap after each flush. Your toilet’s flushing power can be impacted over time as calcium deposits build over the siphon jet.
Solution: Toilet cleaner and brush
To clean the jet flush hole, use an acidic toilet cleaner such as Zep along with a brush. Use a small brush that can be inserted into the hole. Twist several times to ensure the passageway is clear.
3) Clogged rim jets
The rim jets (jet holes) are small holes under the toilet rim that allow water to escape from your tank and into your toilet bowl when you flush. Similar to the siphon jet, calcium deposits can build up around the rim jets and block the water flow. This can weaken the flushing power. Every flush should see water flow quickly and forcefully from the jet holes. If this doesn’t happen it’s time for them to be cleaned out.
Solution: Plumbers putty and toilet bowl cleaner
To completely clean the rim jets, first plug them with plumbers putty. Then, pour acidic toilet cleaner in the overflow tube in the toilet tank. This will dissolve any buildup and deposits. After a couple of hours, take out the plumber’s putty and flush several times. Use a brush to remove any remaining debris.
4) Low water level in toilet tank
Your toilet will not flush properly if the water level is too low in its tank. Low water levels can also cause clogging as less pressure flows through the waste pipe.
Each toilet tank has a water level marking that shows exactly how high the water should be. The marking should be just below the overflow pipe on a standard toilet. A water level below that marking will most likely be the cause of your poor flushing toilet.
Solution: Adjust height of float
The float is what determines the water level in the toilet tank. The float sits on top of the toilet water and keeps the fill valve shut when it’s not in use. The water from the tank flows into the bowl when you flush the toilet. This causes the float to drop, opening the fill valve, allowing fresh water to enter the tank. The float rises as the water level increases. The fill valve is closed when the float reaches a certain height.
Adjusting the height of the floating float will adjust the tank’s water level. Every toilet has a different adjustment screw, but they all have the same basic function. Adjust the float height to increase water flow in the tank.
5) Low water level in toilet bowl
If the water level inside your toilet bowl is too low it will not flush properly. If your toilet’s tank water level is normal but the water level inside the bowl is low, it is likely that the fill valve device in the tank is defective. If the fill valve cracks or leaks water, it can cause water pressure to be taken away from the tube that fills the toilet bowl.
You can determine if your fill valve is the problem by removing the tank lid and flushing a few times. If water squirts from the top of the fill valve, you have a leak. It can sometimes be difficult to diagnose this problem yourself. If it isn’t obvious, we recommend calling a plumber.
Solution: Replace the fill valve
You will need to replace the faulty fill valve apparatus with a new one. If you have never attempted this before, it can be a little difficult. This video will show you exactly how it is done.
6) Too much slack in the flapper chain
The flapper is too loose if you have to hold the toilet handle down for a while to get a good flush.
The flush handle is connected to the flapper valve by a rod and chain. Pushing the handle down will cause the rod to lift the chain which opens the flapper valve. This allows water from the tank to flush into the toilet bowl. If the chain is too long the flapper will close too fast and not allow enough water to flush.
Solution: Shorten the flapper chain
To shorten the slack, most flapper chains come with a clip that can be easily pinned onto another link. You can cut your chain with a wire cutter if it doesn’t. The flapper will be easier to open and will stay open longer if you reduce the chain’s slack. This adjustment allows you to control the amount of water that is flushed into the toilet.
7) Plumbing vent system
Many homeowners don’t know that plumbing needs to be properly vented, just like other parts of their home. The plumbing vent system controls air pressure, moves water through pipes, and removes gas or odors.
If the plumbing vent system is not working properly, it can affect water pressure, drainage, or flushing power. If you smell sewer gas or hear gurgling in your drains, it is usually an indication that something is wrong with the venting.
Solution: Call a professional plumber
Call a plumber immediately if you suspect your toilet is having a weak flush because of a vent system problem. You won’t be able to fix vent systems on your own.
The plumber will inspect your roof’s vent pipe and use special equipment to find the blockage. Once found, they will break it up and flush it out.
8) Water displacement
Some homeowners try and save money on their water bill by placing an object in their toilet tank to displace the water. Although this technique saves money and water, it can negatively impact your flushing power.
Solution: Use a smaller displacement object
Either remove the object from your toilet tank or use a smaller one.
Final thought on weak toilet flush
It is common for homes to have weak flushing toilets. If none of our above solutions work then you should not hesitate to call a professional plumber.
