How Do You Tell If Your Floor Drain Is Connected to a Sanitary Sewer?

Start by looking at where the floor drain sits. In a basement or garage, a floor drain that connects to a sanitary sewer is usually tied into the same waste pipe system as your toilets and sinks. If the drain is near a bathroom or laundry area, it likely shares the sewer line.

Trace the pipe visually if you can. Look for a pipe that runs horizontally and joins a larger vertical stack. That stack is the main sewer vent. If your drain connects to it, it is almost certainly a sanitary sewer connection.

Many homes have a cleanout plug on the sewer line, often in the floor or wall near the drain. If you see a capped pipe with a square or hexagonal nut, that is a cleanout. It gives you direct access to the sewer line, which means your drain is likely tied to it.

If you find a cleanout, you can open it carefully to inspect the pipe. Do not open it if water is standing in the drain, as waste could back up. A plumber can use a camera to confirm the connection without guessing.

If you cannot tell by looking, or if you smell sewer gas, call a plumber. A plumber can run a camera through the drain to see exactly where it leads. This is especially important if you are planning a remodel or adding a new fixture.

If you live in Detroit, keep the location of your main cleanout written down. That helps in an emergency. A plumber can also check for leaks or damage in the line, which can cause water damage over time.