Sewage Smell in the House: What It Means

A sewer smell indoors nearly always means the barrier that normally blocks it has stopped working. Under every drain is a U-shaped bend called a trap that holds a little water, and that water is what keeps sewer gas out of your house. If a trap dries out, or a vent is blocked, the smell has a clear path in. Start with the drains you rarely use, because that is the usual answer and it is free.

What to do right now

• Pour a jug of water down every drain you do not use often. Guest bathrooms, floor drains in the garage or laundry, unused showers. If the smell fades over the next day, a dried trap was the cause and you have fixed it.
• Work out where the smell is strongest and when. A smell in one room points at that fixture. A smell everywhere, or one that comes and goes with the wind, points at venting.
• Check whether the toilet rocks at all when you sit or lean on it. Movement can break the seal underneath, and that is a common source of a bathroom smell.
• Notice whether drains gurgle. Gurgling plus a smell usually means air is being pulled through a trap, which points at a venting problem rather than a dry one.
• If the smell is strong and constant and the water trick does not help, call. Sewer gas is not something to live with while you experiment.

Likely causes

• A dried-out trap. The U-bend under a drain holds water, and that water is the seal. In a guest bathroom, a floor drain or an unused shower, it simply evaporates, and once it is gone there is nothing between you and the sewer line.
• A blocked or damaged vent pipe. Your drains need air to flow properly, supplied by pipes that run up through the roof. If one blocks, traps can get siphoned dry as water drains past.
• A failed seal under a toilet, so gas escapes around the base rather than going down the pipe.
• A crack or open joint in a drain pipe, sometimes inside a wall or under the floor, which lets gas out where it should be contained.
• A dry or missing trap primer on a floor drain, which is a small device meant to keep water topped up in drains that are rarely used.

When to call a pro

If the quick fixes do not solve it, this is usually a sewer line repair & camera inspection job. Liberty dispatches 24/7 with upfront pricing.