Sewer Backing Up When It Hasn't Rained? What It Usually Means

A sewer backup that shows up on a dry day is easy to mix up with a storm problem. The two can look similar inside the house, but dry weather does not rule out a blockage already inside the line. Here is what to observe, what to do right now, and how an inspection can help identify the cause.

Quick answer

Dry weather does not rule out a sewer backup. A blockage can still come from grease or wipes, roots entering at a joint, a sagging or broken section, or material near the cleanout. If more than one drain backs up, stop using water and call. Stay away from sewage. A camera inspection shows what is actually in the line before anyone digs.

Signs it is the main line, not one drain

A single slow sink or shower can still be a local clog. These patterns point further down the shared line:

• The lowest drain in the house backs up first, often a basement floor drain, a first-floor shower, or a basement toilet.
• More than one fixture is slow, gurgles, or backs up around the same time.
• A toilet gurgles when a sink drains or the washing machine empties.
• You notice a sewage odor near a drain or in the yard over the line.

If only one fixture is affected and others still drain normally, the restriction may still be close to that fixture. If several fixtures are involved, treat it as a main-line issue until a plumber shows otherwise.

What can cause a backup when it has not rained

Stormwater is not required for a sewer line to fail. Common inside-the-line causes include:

• Grease, wipes, and other debris that do not break down in the pipe. Products sold as flushable wipes, and paper other than toilet paper, can collect and catch more material over time.
• Roots entering at a joint or crack and then catching grease and paper.
• A sagging section, sometimes called a belly, or a broken, offset, or collapsed piece of pipe that lets waste collect.
• A blockage at or near the cleanout.

These are possibilities, not a diagnosis for your house. The City of Marietta's water and sewer FAQ states that nearly all service-line blockages result from material entering the sewer from the building or from root intrusion near the service line on private property (Marietta Power & Water FAQs). What is actually in your line is something a camera can show.

If backups line up with storms instead of dry weather, see our guide to sewer backups after heavy rain.

What to do right now

1. Stop adding water. Pause laundry, dishwashers, showers, and extra flushing so you do not push more sewage into the house.
2. Keep people and pets away from sewage. The CDC advises staying out of floodwater and sewage when you can. If you must clean, it recommends rubber boots, waterproof gloves, and goggles, then washing with soap and clean water (Floodwater safety; Cleaning safely after a disaster).
3. Do not pour chemical drain cleaner into a main line. Corrosive formulas can burn skin and eyes and can leave caustic liquid in the pipe (What's in drain cleaner; Caution with caustics).
4. If you know where the sewer cleanout is, note it for the plumber. Do not open a cleanout if sewage is already overflowing or you are not sure how to cap it again. Our guide to sewer cleanout access explains what that fitting is for.
5. Note which drains were affected and when it started.

How a camera inspection finds the cause

Guessing from the symptoms alone can send a repair in the wrong direction. A camera inspection runs a video head through the line so the plumber can see whether the problem is a blockage, roots, a sag, a break, or something else, and roughly where it sits. Our guide to how much of a sewer line a camera actually inspects covers what that visit typically shows.

Cleaning versus repair

If the camera shows a blockage in pipe that is still structurally sound, cleaning may be the next step. A cable can clear some obstructions. Stubborn grease or root masses may need a different method. Our comparison of hydro jetting and drain snaking explains when each is used.

If the camera shows a broken, offset, sagging, or collapsed section, cleaning alone will not make the pipe whole. Repair or replacement may be needed. See sewer line repair or replacement.

Questions people ask

Is a sewer backup an emergency?

Sewage in the home is a health concern, not just a mess. Stay out of it, stop using water, and request service. Ask the office about current availability.

Can I use a chemical opener on a main line?

No. Chemical drain openers are not a safe way to clear a main sewer line, and they can leave a hazardous liquid for whoever opens the pipe next (Poison Control articles linked above).

Who is responsible for the line from the house to the street?

It depends on which utility serves your address, so confirm with them rather than assuming one rule covers every Marietta-area home.

For customers of Marietta Power & Water, the city's FAQ says it is the property owner's responsibility to remove a service-line blockage even if the blockage is in a road right-of-way or a sewer easement. The Water and Sewer Department may help remove a blockage in a public right-of-way or a BLW easement if you have hired a licensed plumber or contractor who cannot restore service. The line must be exposed and the contractor present. If pipe failure in those public areas caused the blockage, the department repairs the line there (Marietta Power & Water FAQs).

For customers of Cobb County Water System, county wastewater rules state that property owners are responsible for construction and maintenance of the service line from the premises served to the point of connection with the county service lateral (Cobb County Code, general use of public water and wastewater facilities). The county's pipe-ownership page also explains that a county sewer line in a permanent recorded easement is owned and maintained by the county (Pipe ownership).

Request a sewer line inspection

If more than one drain is backing up on a dry day, request sewer line service from bluefrog Plumbing + Drain of Marietta. Tell us which drains are affected, when it started, and whether there is sewage in the house or yard.