How to Fix a Toilet That Won’t Flush Well

Updated: Dec. 13, 2022

In new or recently remodeled houses, the fix is sometimes unusual — and ridiculously simple

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If your expensive new toilet won't flush properly and the contractor is giving you the runaround, climb up on the roof and check the vent pipe.

Tools Required

  • 4-in-1 screwdriver
  • Extension ladder

Master baths are often distant from the rest of the plumbing in the house, so they often have their own plumbing vents independent of the home’s other plumbing. If the flushing performance is anemic and there are no clogs or obvious malfunctions, there may be an amazingly simple remedy to fix a toilet that won’t flush correctly.

Project step-by-step (1)

Step 1

Inspect the Vent

    • Note: Occasionally, plumbers forget to remove the temporary plug that’s used to pressure-test the lines after plumbing rough-in. They’re located at the top of the vent pipe up on the roof.
  • From ground level, check if you can see a rubber cap clamped on the vent over the bathroom.
  • If you can’t see it, grab a screwdriver, and climb up on the roof and inspect the end of the vent over your bathroom.
  • If the overlooked plug is intact, break through the plastic with a screwdriver and pry out the pieces — the toilet should work just fine.

Toilet, Flushing Water, close upAm.p/Shutterstock

If the plug isn’t the problem, you probably have a defective toilet or an obstruction in the drain line. Get ahold of the plumber who worked on the house. He or she should be able to solve the problem.