When a toilet won’t flush, stop the water first, then work out whether the problem is in the tank, the bowl’s trapway, or the drain beyond the toilet. If the bowl is rising, close the supply valve behind the toilet before you try anything else. Flushing again just adds water.

1. Check the tank before you plunge

Lift the lid and flush. If little water rushes into the bowl, the problem may be the tank, not a clog. Korky lists the usual tank-side causes:

  • Chain: too slack and the flapper won’t lift fully. Korky recommends leaving 1 to 2 links of slack.
  • Water level: too low a fill leaves too little water for a strong flush. Set the fill valve to the level the toilet maker marks.
  • Flapper: the wrong size (standard 2-inch vs. 3-inch) or a bad setting on an adjustable flapper can cut the flush short.
  • Rim jets: mineral deposits in the holes under the rim weaken the flush.

If the tank checks out and the water sits in the bowl, you have a clog.

2. Plunge with a flange plunger

Use a flange plunger (the kind with a sleeve that fits into the toilet’s drain opening), not a flat sink plunger. Make sure there’s enough water in the bowl to cover the cup, seat it, and use firm, controlled strokes. If the water starts to drain, flush once to test with the supply valve within reach.

3. Use a closet auger

If plunging doesn’t move it, Kohler’s advice for water that won’t leave the bowl is to use a toilet auger or snake to free the clog from the trapway. A closet auger is shaped to feed through the toilet’s built-in bend. Feed it in, crank gently, and pull it back to retrieve wipes or an object. Stop if it hits something hard and won’t advance. Forcing it can damage the bowl or push the object deeper.

When you buy one, look for a protective sleeve or guard at the bowl end to help avoid scratching the porcelain. Short closet augers handle the toilet itself. A longer drain snake is a different tool for lines past the toilet.

4. Watch the other drains

Kohler says newer toilets rely on adequate venting, and lists these signs of a venting or drainage problem:

  • Water rising in the bowl
  • A slow flush, with water rising quickly and falling slowly
  • Frequent clogs
  • Having to hold the handle down
  • Sounds from other drains when you flush
  • Bubbles from the trapway during the flush

If a tub, shower or sink gurgles or backs up when you flush, stop plunging. The blockage or restriction is past the toilet, and more water won’t clear it. Call a plumber.

Stop and call a plumber if

  • Other fixtures back up
  • The auger won’t pass the obstruction
  • The toilet rocks, leaks at the base or smells of sewage
  • The bowl or tank is cracked

Mistakes to avoid

  • Flushing repeatedly to “push it through”
  • Using a flat sink plunger
  • Pouring chemical drain cleaner into a clogged toilet, which leaves caustic water in the bowl for whoever plunges next
  • Forcing an auger against a hard stop
  • Ignoring a weak flush after the clog clears

FAQ

Why does the handle move but nothing happens?

The flush isn’t reaching the bowl. Check that the chain is attached and not too slack. Korky recommends 1 to 2 links of slack. Also check that the flapper lifts and the tank actually refilled.

Is a closet auger safe for a toilet?

A closet auger (toilet auger) is the tool Kohler points to for clearing a clog in the trapway. Choose one with a protective guard at the bowl end, turn it gently, and stop if it won’t advance.

Why does the toilet clog again right after it clears?

Either part of the clog is still there, or the flush is weak. Korky lists a slack chain, a low tank water level, the wrong flapper size and mineral-clogged rim jets as common causes of a weak flush.

When does a clog mean the main line or vent is the problem?

When other fixtures react. Kohler lists sounds from other drains when flushing, bubbles from the trapway, slow flushes and frequent clogs as signs of a venting or drainage problem rather than a simple bowl clog.

Sources