Stop it in the first 30 seconds

  1. Close the supply stop.The oval handle on the wall behind the toilet. Turn it clockwise until it stops.
  2. Lift the flapper if needed.If you cannot reach the valve, take off the tank lid and push the rubber flapper down to stop water entering the bowl, or lift the float to stop the fill.
  3. Do not flush again.A second flush adds more water to a bowl that cannot drain.
  4. Protect the floor.Lay down towels and keep people out. If the water came from the bowl after flushing, treat it as contaminated.

Plunge it properly

A flange plunger, the kind with a soft extension at the bottom, seals far better in a toilet than a flat sink plunger.

  1. Leave some water in the bowl.The plunger needs water to push, not air. Remove excess if the bowl is near the rim.
  2. Seal and push gently.Fit the flange into the outlet and start with a gentle push so you do not splash.
  3. Work it steadily.Use firm in-and-out strokes for 15 to 20 seconds, keeping the seal.
  4. Test with the supply off.Pour a bucket of water into the bowl to see whether it drains before opening the supply stop again.

Toilet clog or main line?

  • IfOnly this toilet backs up and other drains are fineLikely a clog in the toilet or its drain. Plunging or an auger usually clears it.
  • IfFlushing makes water rise in the tub or showerLikely a main line blockage. Stop all water use and call a plumber.
  • IfSeveral toilets or drains gurgle or back up togetherTreat it as a main line problem, not a toilet problem.
  • IfIt clears but clogs again within daysHave the drain line inspected, possibly with a camera.

Common causes

  • Wipes, even those labeled flushable, and paper towels.
  • Too much toilet paper in one flush.
  • Hygiene products, cotton swabs and floss.
  • Small toys or objects dropped in by children.
  • Roots or a break in an older cast-iron or clay lateral, if the problem is further down.

When a plumber is the right call

If plunging and a toilet auger do not work, an object may be lodged in the toilet's trap, and the toilet may need to be pulled to remove it. That also means resetting it with a new wax ring or seal, which is worth having done properly to avoid slow leaks into the subfloor.

If the backup shows up anywhere else in the house, it is no longer a toilet problem. It is a main line problem, and the next step is clearing the line and finding out why it blocked.

Questions to ask

  1. Was the clog in the toilet or the line beyond it?
  2. Does the toilet need to be pulled and reset?
  3. Should the main line be inspected?
  4. What is your CSLB license number?

Common questions

Is an overflowing toilet an emergency?
Once the supply is off and it is the only affected drain, it can usually wait until morning. If sewage is rising in other drains, treat it as urgent.
Why does my toilet keep running after it overflowed?
The fill valve or float may be stuck. Keep the supply stop closed until it is repaired.
Can I use another toilet in the house?
Only if the clog is confirmed to be in the first toilet. If other drains are slow, stop using all of them.

General information for Brea, not a quote or professional advice. In an emergency, call 911.