The short answer
A sewer cleanout is a capped pipe, usually 3 or 4 inches across, that opens straight into your main sewer line. In most Northern Virginia houses it’s outside, within a few feet of the foundation on the side toward the street, sticking a few inches out of the ground with a plastic or metal cap. In older houses it’s often inside: low on the wall or in the floor of the basement where the main drain leaves the house. It’s the fastest way into the line when it clogs, and in a backup, one look in it tells you where the clog is.
Where to look
- Outside along the foundation, on the side facing the street. Check mulch beds and behind shrubs. They get buried.
- Between the house and the street, in line with where the sewer runs. Some houses have a second one near the property line.
- In the basement, at the bottom of the main stack, the big vertical drain pipe: a fitting with a threaded plug and a square nut on top. Or a plug in the floor near the front wall.
- In a crawlspace, near where the main line goes through the foundation.
- In a townhouse, sometimes in a utility closet or under the stairs, sometimes in the front yard strip.
The quick way to find it: find the main stack in the basement, see which wall the line heads toward, and look outside on that side.
Don’t mix it up with the water meter box (a lid flush with the ground near the street, usually marked water), a sprinkler valve box, a radon pipe on the side of the house, or a downspout drain. The cleanout is a pipe with a cap, and the cap often has a square knob or a slot.
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What it tells you in a backup
If drains are backing up, open the outside cleanout cap and look in. Turn it slowly with an adjustable wrench and stand to one side, because a full line can push the cap off.
- Full of water: the clog is between the cleanout and the street.
- Dry or draining: the clog is between the cleanout and the house.
That one look tells a plumber where to start, and saves time on the call. On a house built on a slab or over a crawlspace, where the outdoor cleanout is lower than every drain inside, loosening the cap can let a backup spill in the yard instead of a bathroom. In a house with a basement, the floor drain is lower, so stop using water instead. Don’t open a cleanout inside the house during a backup: if the line is full, it comes out on your floor. One drain or the main line has the signs of a main line clog.
Why it matters on the bill
With a cleanout, the drain machine or the water jetter goes straight into the main line. Without one, we go in through a toilet, which means pulling it, or up on the roof through the vent. That’s more time, not no service. Main line clearing runs $550 to $1,650 either way, and you get the price before we start. If your house has no cleanout, adding one while we’re there makes every future call faster, and we’ll price that before we start too. A sewer camera goes in the same way, $89 added to a visit.
Keep it usable
- Don’t bury it under mulch, stone or a new patio. Mark it if the grass grows over it.
- Replace a cracked cap. Mowers break them, and an open cleanout lets rainwater, dirt and roots into the line. Hardware stores carry them by size.
- Never run a downspout or a sump pump into it. Rainwater isn’t allowed in the sewer, and it fills the line in a storm.
- Old cast iron plugs seize. If yours won’t turn, leave it for the plumber rather than cracking the fitting.
Who owns the line
The line from the house to the public sewer is usually the homeowner’s to keep up, at least to the property line. Where yours ends and the utility’s begins depends on the sewer utility, whether that’s Fairfax County, Loudoun Water, Arlington County, Prince William Water or your town, so ask yours. If the line in an older house keeps clogging, it may be tar paper pipe: what Orangeburg pipe is.
When you’d rather we do it
A sink clogged at the trap is $99 with our sink clearing offer, up to the P-trap. A toilet, tub, shower or any drain past the trap is drain cleaning, $200 to $800. The main line to the street runs $550 to $1,650, and when grease or roots keep coming back, hydro jetting clears the pipe wall. You get the price before we start. A plumbing diagnosis visit is $49, or $250 after hours.
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Questions people ask
Where is my sewer cleanout?
Usually outside within a few feet of the foundation on the side toward the street, a capped pipe a few inches out of the ground. In older houses, look in the basement where the main drain leaves, for a fitting with a threaded plug.
Can I open my sewer cleanout myself?
Yes, slowly, standing to one side, with an adjustable wrench. If it’s full of water, the clog is toward the street. Don’t open one inside the house during a backup.
What if my house doesn’t have a sewer cleanout?
A plumber goes in through a toilet or the roof vent, which takes more time. Adding a cleanout makes every future call faster.
Is the sewer cleanout the same as the water meter?
No. The water meter box is a lid in the ground near the street, usually marked water. The cleanout is a pipe with a cap.
Who is responsible for the sewer line in Northern Virginia?
Usually the homeowner, at least from the house to the property line. Where it changes depends on your sewer utility, so ask Fairfax County, Loudoun Water, Arlington County, Prince William Water or your town.
