At the street, stop 1 of 6

Find the sewer cleanout in your yard

A sewer cleanout is a capped opening on the pipe carrying waste away from your house, and it is how a plumber reaches a clog. Most look like a short pipe with a screw cap, or a small lid in the ground, somewhere between the foundation and the street.

Stand where the house drains leave the foundation, then walk toward the street with your eyes on the ground.

Updated November 4, 2026, Midlands House Walk

Leave the cap on when a drain is backing up. Sewage held in the line can push out as the cap loosens, and you would be standing right over it. The first hour of a backup is a separate page.

Square cast-iron plate stamped with the words sewer cleanout, set in concrete — A cast-iron cleanout lid in Ontario, Canada. The stamped words make it easy. Yours may be plainer, so check any small lid along the sewer’s path.

Dark threaded cap standing just above the grass beside a pine straw bed — A dark threaded cap at the edge of a pine straw bed. Mulch and tall grass hide these, so part the edges of your beds with a foot. AI-generated picture.

A dark cap at the edge of a bed

Look for: Check the lawn and bed edges between the house and the curb for a round cap with a square or slotted head. It takes a wrench, so it won’t look like a sprinkler part.
What it tells you: That cap sits on the sewer line, so it gives you one fixed point on the pipe’s route. In Columbia Water’s area the line up to the property line is the homeowner’s to maintain¹, so a cracked cap there is likely yours. Who owns which stretch has its own stop.

White plastic pipe with a white screw cap rising from mulch beside a red brick wall — A white plastic cleanout beside a brick wall, the style you may find on newer or repaired lines. Look on the side of the house nearest your bathrooms. AI-generated picture.

A white cap against the brick

Look for: Walk the foundation slowly. A short white pipe with a screw cap, standing a little above the mulch, is easy to mistake for a vent or an old irrigation stub.
What it tells you: Close to the wall usually means close to where the line leaves the house, which gives a plumber a short run to the blockage. A cap cracked by a mower lets rain and dirt in, so note it and get it replaced.

Dark cast-iron drain pipes visible through a cut opening in a wall, next to a wood stud — Cast-iron drain pipes showing through an opened wall. Older houses often used this material, and a threaded plug on it can serve as the way in.

Older drains may hide theirs indoors

Look for: No cap in the yard? In an older house, look for a threaded plug on a cast-iron drain in a closet or utility space, or from the crawlspace hatch with a flashlight.
What it tells you: You may have an indoor cleanout, or none at all, and a plumber can tell you which. Clemson’s way of tracing a septic line helps here too: follow the 4-inch sewer pipe from the crawlspace outward².

What if the house is on septic?

You still have a sewer pipe, but it heads for a tank instead of the street, so the cap may sit in the back yard. Finding the tank starts from the same pipe.

Yours to do

Take a phone photo of the cap with the house in the background, so you can find it in a hurry.
Keep soil and mulch off it, and mow around it.
Scrape plates and put cooled grease in a jar or can for the trash³, which keeps the line clear in the first place.
Think it’s buried? Stop there, because digging starts with SC811, three business days ahead⁴.

For a licensed pro

Opening the cap and running a cable through a blocked line.
Replacing a cracked cap or a seized plug.
Adding a cleanout to a line that has none, and asking the local building office whether that needs a permit.

Where this comes from

Keep walkingWho owns the sewer line under your yard?