Or you can seal the drain with a 2-in. test plug, also sold at home centers. A plug will stop rising sewage, but you’ll have to remove it every time you want to use the drain.

How To Get Rid of Smelly Drains For starters, if the water in your p-trap has evaporated, pour a bucket of water down the drain to refill the trap. Then add the oil, about a teaspoon for each inch ...