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Fix a toilet that flushes slowly

We'll clean the rim jets, adjust the water level, and clear partial clogs—or tell you when to call a plumber for a blocked drain.

Troubleshooting · Home plumbing
15–30 min
What you'll need
  • Bent wire, paper clip, or small brush (for rim jets)
  • Flange plunger
  • Vinegar (optional, for mineral buildup)
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Steps

Goal: Restore a strong flush by cleaning rim jets, adjusting water level, and clearing partial clogs.

  • Flush the toilet. If water drains but the flush is weak, you have a slow flush. If it does not drain at all, see fix-toilet-is-clogged.
  • Good: Slow flush. Proceed to Clean rim jets first.
  • Bad: Complete clog. See fix-toilet-is-clogged or call a plumber.

Clean rim jets first

Goal: Clear mineral buildup from the rim jets so water flows properly.

  • The rim jets are small holes under the bowl rim. Use a bent wire, paper clip, or small brush to clear each hole.
  • Flush to rinse debris. Check that water streams from all jets.
  • Good: Water flows from the jets. Test the flush. See Verification.
  • Bad: Jets were clear—check Adjust water level.

Adjust water level

Goal: Raise the water level in the tank if it is too low for a strong flush.

  • The water level should be about 1 inch below the overflow tube. If low, adjust the fill valve float or clip.
  • Flush and test. A higher level provides more water for the flush.
  • Good: Flush is stronger. See Verification.
  • Bad: Still slow—proceed to Plunge.

Plunge

Goal: Clear a partial clog in the trap or drain.

  • Use a flange plunger. Seal it over the drain and push and pull firmly several times.
  • Flush to test. If the flush improves, the partial clog is cleared.
  • Good: Flush is stronger. See Verification.
  • Bad: No improvement or toilet backs up—call a plumber.

When to get help

Call a plumber if:

  • The toilet backs up or will not drain.
  • The slow flush continues after cleaning jets, adjusting water level, and plunging.
  • You suspect a blockage in the main drain line.

Verification

  • Water streams from all rim jets when flushing.
  • Water level in the tank is about 1 inch below the overflow tube.
  • The toilet clears the bowl with a strong siphon and refills normally.

Escalation ladder

Work from the device outward. Stop when the problem is fixed.

  1. Confirm symptom Verify the flush is slow, not completely blocked.
  2. Clean rim jets Clear mineral buildup from the rim jets.
  3. Adjust water level Raise the water level in the tank if low.
  4. Plunge Clear a partial clog with a flange plunger.
  5. Call a pro Toilet backs up or slow flush persists—call a plumber.

What to capture if you need help

Before calling support or posting for help, have these ready. It speeds everything up.

  • Whether the toilet drains at all or backs up
  • Water level in the tank
  • Rim jet condition
  • Steps already tried

Does the toilet drain but flush weakly?

Slow flush: water drains but with reduced force. Complete clog: water does not drain or backs up.

Flush the toilet. Good: water drains but the flush is weak or sluggish—slow flush. Bad: water does not drain or backs up—clog; see fix-toilet-is-clogged or call a plumber.

Yes No

You can change your answer later.

Are the rim jets blocked?

Rim jets are small holes under the bowl rim. Mineral buildup blocks them.

Look under the bowl rim. Use a bent wire or brush to clear each rim jet hole. Flush to rinse. Good: water now flows from the jets—test flush. Bad: jets were clear—check water level.

Yes No

You can change your answer later.

Is the water level in the tank low?

Water should be about 1 inch below the overflow tube. Low level = weak flush.

Check the water level in the tank. It should be about 1 inch below the overflow tube. If low, adjust the fill valve float to raise it. Good: level was low, now correct—test flush. Bad: level was fine—try plunging for partial clog.

Yes No

You can change your answer later.

Does plunging improve the flush?

A partial clog in the trap can cause a slow flush. Use a flange plunger.

Use a flange plunger. Seal over the drain. Push and pull firmly several times. Flush. Good: flush improves—partial clog cleared. Bad: no improvement or toilet backs up—call a plumber.

Yes No

You can change your answer later.

Is the flush now strong?

Test the flush after cleaning jets or adjusting water level.

Flush several times. Good: strong flush, bowl clears—fixed. Bad: still slow—try plunging or call a plumber.

Yes No

You can change your answer later.

Flush fixed

The flush is now strong. Monitor to confirm.

Done

Call a plumber

Call a plumber if: the toilet backs up or will not drain; the slow flush continues after cleaning jets, adjusting water level, and plunging; or you suspect a blockage in the main drain.

Done

Reviewed by Blackbox Atlas

Frequently asked questions

Why does a toilet flush slowly?
Common causes: clogged rim jets (mineral buildup blocks the holes), low water level in the tank (not enough water for a strong flush), or a partial clog in the trap or drain. Cleaning the jets and adjusting the water level often fix it.
Can I fix a slow flush myself?
Yes. Cleaning the rim jets, adjusting the water level, and plunging are DIY tasks. If the toilet backs up or will not drain, you may need a plumber or drain snake.
When should I call a plumber for a slow flush?
Call a plumber if the toilet backs up, will not drain, or the slow flush continues after cleaning jets, adjusting water level, and plunging.

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