Quick answer
If your toilet isn't completely flushing, check the water level in the tank and ensure the flapper is sealing properly. Adjust the float or clean the flapper to improve the flush.
Confirm the symptom
- Toilet flushes weakly or incompletely
- Water continues to run after flushing
- Toilet requires multiple flushes to clear waste
Tools and prep
- Adjustable wrench
- Screwdriver (flathead or Phillips)
- Plunger
- Bucket
- Towel
- Rubber gloves
- Turn off water supply to the toilet before starting repairs
Step-by-step troubleshooting
- Check Water LevelDo: Remove the tank lid and flush the toilet. Observe the water level in the tank.Observe: Water should fall to about 1 inch below the overflow tube.Means: Low water level may prevent a strong flush.Next: Adjust the float if the water level is too low.
- Adjust the FloatDo: Locate the float and adjust it upward to increase the water level.Observe: Water should rise to the correct level and stop.Means: Proper water level ensures a strong flush.Next: Test the toilet by flushing and observing the water flow.
- Inspect the FlapperDo: Check the flapper for wear or mineral buildup. Clean or replace if necessary.Observe: Flapper should create a tight seal when closed.Means: A faulty flapper can cause incomplete flushing.Next: Test the toilet after replacing or cleaning the flapper.
- Check the Chain LengthDo: Ensure the chain connecting the flapper to the flush handle is not too long or tangled.Observe: Chain should have a slight slack but not drag on the tank floor.Means: Improper chain length can prevent the flapper from opening fully.Next: Adjust the chain length if needed and test the flush.
- Clean the Trap and P-TrapDo: Use a plunger to try clearing any blockages in the trap and P-trap.Observe: Water should drain freely after plunging.Means: Blockages can restrict water flow and cause incomplete flushing.Next: If plunging doesn't work, consider using a toilet auger.
- Inspect the Fill ValveDo: Check the fill valve for proper operation and adjust if necessary.Observe: Valve should shut off when the tank is full.Means: A malfunctioning fill valve can lead to low water levels.Next: Replace the fill valve if it's not working correctly.
Common causes
| Cause | Likelihood | Difficulty | Part often needed |
|---|---|---|---|
| Low Water Level Insufficient water in the tank reduces flushing power. | Common | Easy | Float adjustment or replacement |
| Faulty Flapper A worn or improperly sealed flapper allows water to leak, reducing flush strength. | Common | Easy | Flapper replacement |
| Clogged Trap or P-Trap Blockages restrict water flow and prevent complete flushing. | Sometimes | Easy–Medium | Toilet auger or plunger |
| Incorrect Chain Length A chain that's too long or too short prevents the flapper from opening fully. | Sometimes | Easy | Adjustable chain or new flapper chain |
| Malfunctioning Fill Valve A faulty fill valve may not fill the tank to the proper level. | Sometimes | Medium | Fill valve replacement |
| Worn-Out Flapper Valve Over time, the flapper can deteriorate and fail to seal properly. | Common | Easy | New flapper valve |
Parts matching
Common parts needed for fixing a toilet that doesn't flush completely include:
- Flapper valve
- Fill valve
- Toilet float
- Toilet auger
- Plunger
- Chain for flapper
- Toilet tank lid
Purchase replacement parts that match your toilet model for the best results.
When to call a professional
- The toilet still doesn't flush completely after trying all troubleshooting steps
- There is a persistent blockage that cannot be cleared with a plunger or auger
- Water continues to leak from the tank or bowl despite repairs
- You notice cracks or damage to the toilet tank or bowl
- You are unsure about making repairs and need professional assistance
FAQ
How do I know if my toilet flapper needs replacing?
If the flapper doesn't create a tight seal or shows signs of wear, it may need to be replaced. Check for cracks or mineral buildup.
Can a low water level cause a weak flush?
Yes, a low water level in the tank can significantly reduce the flushing power of your toilet.
What should I do if my toilet still doesn't flush after adjusting the float?
If adjusting the float doesn't improve the flush, check the flapper, chain length, and fill valve for issues.
Is it normal for my toilet to require multiple flushes?
No, a properly functioning toilet should flush completely with a single flush. Multiple flushes indicate an underlying issue.
How often should I clean my toilet trap?
It's a good idea to clean the trap and P-trap periodically to prevent buildup and maintain proper flushing.