Toilet Not Emptying Completely: Fixes & Solutions

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Quick answer
Confirm the symptom
Tools and prep
Step-by-step troubleshooting
Common causes table
Parts matching
When to call a pro
FAQ
Related guides

Quick answer

If your toilet isn't emptying completely, first check for a clog using a plunger or auger. Adjust the flapper chain if it's too tight or loose. Ensure the water level is correct in the tank.

Confirm the symptom

Toilet water level is higher than usual
Toilet gurgles after flushing
Water remains in the bowl after flushing
Toilet flushes weakly or slowly

Tools and prep

Rubber plunger
Toilet auger (snake)
Adjustable wrench
Screwdriver
Bucket
Work gloves
Turn off water supply to the toilet
Wipe up any standing water before starting

Step-by-step troubleshooting

Check for Clogs
Do: Use a plunger to try to dislodge any blockages in the drain.
Observe: Water level in the bowl may drop if the clog is cleared.
Means: A clog is likely the issue if the water drains after plunging.
Next: If the clog is cleared, move to Step 2. If not, proceed to Step 3.
Use a Toilet Auger
Do: Insert the auger into the drain and rotate it to break up or remove the clog.
Observe: You may feel resistance or see the clog being pulled out.
Means: The clog is deeper and requires a more thorough removal.
Next: After clearing the clog, flush the toilet to check if it empties completely.
Adjust the Flapper Chain
Do: Check the chain connecting the flapper to the flush handle. Adjust it so there's a slight slack.
Observe: The flapper should open fully when you flush.
Means: A too-tight or too-loose chain can prevent the flapper from sealing properly.
Next: Test the flush to see if the water level in the tank is correct.
Check Water Level in Tank
Do: Ensure the water level is about 1 inch below the overflow tube.
Observe: Water should not be spilling into the overflow tube.
Means: If the water level is too high, it can cause incomplete flushing.
Next: Adjust the float if necessary and test the flush again.
Inspect the Flapper Valve
Do: Remove the tank lid and check the flapper for wear or mineral buildup.
Observe: The flapper should close tightly after each flush.
Means: A damaged or worn flapper can cause water to leak into the bowl, leading to incomplete flushing.
Next: Replace the flapper if it's damaged or not sealing properly.
Check the Siphon Jet and Trapway
Do: Clean the siphon jet (the hole under the water in the bowl) and the trapway with a brush or vinegar solution.
Observe: Debris or buildup should be removed, allowing water to flow freely.
Means: Clogs or buildup in these areas can restrict water flow and cause incomplete flushing.
Next: Flush the toilet to see if it empties completely now.

Common causes

Cause	Likelihood	Difficulty	Part often needed
Clogged Drain A blockage in the drain pipe prevents water from flowing out of the bowl.	Common	Easy	Toilet auger
Improper Flapper Adjustment A flapper that's too tight or too loose can prevent the tank from emptying fully.	Common	Easy	Toilet flapper
High Water Level in Tank If the water level is too high, it can overflow into the overflow tube, reducing the amount of water available for a proper flush.	Common	Easy	Float adjustment
Worn Flapper Valve A damaged or worn flapper may not seal properly, causing water to leak into the bowl.	Sometimes	Easy	Toilet flapper
Clogged Siphon Jet or Trapway Buildup in the siphon jet or trapway can restrict water flow and cause incomplete flushing.	Sometimes	Easy–Medium	Toilet brush or vinegar solution
Faulty Fill Valve A faulty fill valve may not allow enough water to refill the tank properly after each flush.	Rare	Medium	Fill valve replacement

Parts matching

Common parts needed for fixing a toilet that doesn't empty completely include:

Toilet plunger
Toilet auger
Toilet flapper
Float adjustment kit
Toilet brush
Vinegar or cleaning solution
Fill valve (if needed)

Purchase a toilet flapper and auger as they are most commonly needed for this issue.

When to call a professional

The toilet still doesn't empty completely after multiple attempts to clear the clog.
You notice a persistent foul odor or water leakage around the base of the toilet.
You suspect a major blockage in the main sewer line.
You're unsure about how to adjust the flapper or fill valve.
The toilet is old and may need a full replacement.

FAQ

How often should I clean my toilet's siphon jet and trapway?

It's recommended to clean these areas every 3–6 months to prevent buildup and ensure proper flushing.

Can a high water level in the tank damage my toilet?

Yes, a high water level can cause water to continuously run into the overflow tube, leading to water waste and potential damage over time.

What should I do if the flapper doesn't seal properly?

Replace the flapper with a new one and ensure the chain is adjusted correctly for proper sealing.

Is it normal for the toilet to gurgle after flushing?

A slight gurgle is normal, but if it's frequent or loud, it may indicate a blockage or venting issue.

Can I use a chemical drain cleaner for a toilet clog?

It's not recommended to use chemical drain cleaners in toilets, as they can damage the porcelain and plumbing.