A leaky vent pipe allows stinky sewer gases into the home and can even lead to an explosion caused by the methane in these gases. While leaks in a plumbing pipe are often easy to spot due to the presence of water, detecting a leak in drain, waste and vent piping can be trickier because these pipes vent only gas. Pungent peppermint oil serves a simple means of ensuring that newly installed DWV pipes are air-tight and of spotting leaks in existing systems.
Ensure that all plumbing fixtures are set and connected, and that all traps are filled with water. Close all doors and windows to the home.
Access the drain-waste-vent pipe on your roof. Pour 2 ounces of peppermint oil into the pipe, followed by 10 quarts of hot water. Cap the vent pipe.
Remain outside for the duration of the peppermint oil test once you've poured the oil and water into the vent. The person who pours the peppermint carries the smell on his hands or clothes and won't be able to properly detect the smell if it manifests inside the home.
Send a friend or family member inside the home. Instruct him to seek out the scent of peppermint and make a note of any location where he notices this distinct odor. Have the helper check around pipe joints and connectors, plumbing fixtures and traps, and all fixtures, including toilets, sinks, tubs and basement drains.
Inspect and repair or seal all components where your test partner noticed the smell of peppermint. These spots could be allowing sewer gas to leak into your home.