Backed up main line: is it your pipe or the city's?
A sewer backup is an emergency, and our line is open 24/7. While you wait, stop all water use and keep the family out of the affected room. That much stops the problem from growing.
Your house drains into a lateral, a pipe that runs from the foundation toward the street. A blockage inside the house or in that private line is ours to clear. The main sewer in the street is the city's system. Several toilets failing at once, gurgling when another fixture drains, or water in a floor drain are the usual signs of a main-line problem.
Sewage rising: what to do right now
Dirty water in the house carries bacteria, so treat it with caution.
- Stop using every fixture. Do not flush, run the sink, wash clothes or start the dishwasher.
- Keep children, pets and bare feet out of any standing water.
- If water is near outlets, appliances or a panel, do not touch them. Turn a breaker off only if the floor around the panel is dry and you can do it safely.
- Skip chemical drain cleaners. They will not clear a main line and they make it hazardous to work on.
- Call (206) 864-6558, describe which drains are backing up and where the cleanout is.
Call (206) 864-6558 and tell us which fixtures are affected. We answer all hours and give a clear price before work starts.
Who handles which sewer problem
The right contact depends on where the trouble sits.
| What is happening | Whose line | What to do |
|---|---|---|
| Toilets and tubs back up inside the house | Your private line or house drain | Call us at (206) 864-6558 |
| Slow drains and gurgling in one bathroom group | Likely your branch or lateral | Stop water use and call us |
| Sewage or water surfacing in the street or a break in the system | The city's system | Call City Public Works on weekdays, or the county line after hours |
| Water in the floor drain only after heavy rain | Could be either, so we check | Call us and we will look at your side first |
| Sewer smell with no backup | Often a dry trap or a vent issue | Run water in unused drains and call if it stays |
Public Works, the county line and the wet season
For a water or sewer line break in the city system, call Mountlake Terrace Public Works at 425-670-8264, open 7 a.m. to 3:30 p.m., Monday to Friday. After hours, the Snohomish County non-emergency line is 425-407-3999. We can clear and diagnose your private line, but a break out in the street is not ours to fix, so make that call if you see it.
Wet weather matters too. When the ground is soaked from fall to spring, a backup that appears alongside soggy yard patches near the lateral can mean a leak or a break rather than a plain clog. Tell the dispatcher if the yard looks wet, because that changes the plan.
How we clear a main sewer line
We start at the cleanout and send a cable with a cutting head down the line to break through the blockage. Roots are cut back, and grease and debris are pulled loose.
If the cable keeps stalling or the line coats back over quickly, we move to hydro jetting, which scours the pipe wall with high-pressure water. Afterward we run water through the line to confirm the flow. Where the cause is unclear, a camera on a flexible cable shows the pipe, and we can discuss a sewer inspection as a follow-up.
Early warnings before a full backup
The main line often warns you first. These signs mean it is time to call.
- Gurgling toilets. Air is being pushed back through the traps as water struggles to pass.
- Bubbles in the tub or shower when the washer drains. A shared line is slowing down.
- Water around a basement floor drain. The lowest opening is taking the overflow.
- Several fixtures draining slowly. One clog does not do this, but a partial main blockage does.
- A sewer smell that returns. Possible partial blockage or a dry trap.
- Wet patches near the cleanout or lateral. May mean the line is leaking, not just clogged.
What changes the price of sewer line cleaning
Main-line work is priced by what the line needs. These are the factors.
A longer run takes more cable and more time.
Grease and paper clear faster than roots, scale or a collapsed section.
A cable is the simpler option. Jetting costs more but cleans the whole pipe wall.
A good cleanout makes the job simple. Without one, we may need to pull a toilet or work from a vent.
Adding a look inside the pipe takes time but shows the cause.
We give a clear price before work starts, so call (206) 864-6558 for your number. Many homeowners policies cover sudden backup damage only with an added endorsement, and wear or buildup is usually excluded. Check your own policy.
Roots: why a main line clogs again
Roots find the tiny gaps at pipe joints and grow inside the line, because sewer water is a steady source of moisture and nutrients. A cable cuts them back, but they regrow unless the joint is sealed or the pipe is replaced.
If the blockage keeps coming back at the same distance, ask for a camera look. Depending on what it shows, the choice is between regular cleaning and a spot repair.
Living with a blocked main: families, timing and what comes next
A household of several people can fill a blocked line quickly, so the water has to stop. Use another bathroom elsewhere, such as at a neighbor's or a public restroom, until the line is cleared. Do not run the washer or take showers expecting the line to catch up.
We offer same-day appointments when available, and the dispatcher will explain what the visit looks like when you call. For plumbing help just south of us, see our Lynnwood page.
Main line questions, answered plainly
Yes. We answer at (206) 864-6558 around the clock, including nights, weekends and holidays. A backup that started at 2 a.m. is still an emergency, so call, stop using water and we will tell you what happens next. Same-day appointments are offered when available for lines that are slow but not yet backing up.
Look for a capped pipe, usually three or four inches across, near the foundation, in a basement or crawlspace, or in the yard near the front of the house. Do not remove the cap if sewage is backed up behind it. Tell the dispatcher what you found and we will confirm it.
Waste water rises where it can escape, and that is the lowest opening in the house, often a basement floor drain, shower or tub. Backing up there while upper fixtures still drain is a typical sign of a partly blocked main.
A clog inside the house or in your private line is yours to clear. A break or blockage in the city's sewer system is handled by the city. If you are unsure, call us first. If we see signs the problem is outside your pipe, we will say so and point you to the right contact.
Call your landlord or property manager right away, because a main-line backup is usually the owner's responsibility under many leases. Your lease decides. We can speak with the property manager, explain what we find and give a clear price before work starts.
Roots tend to cause repeat blockages at the same spot, and a cable often comes back with fine root fibers on it. A camera on a flexible cable shows them directly. Cutting and jetting clear roots, but they can return.
A sewage ejector pump lifts waste up to the main line. If only that bathroom backs up, the pump or its check valve may be at fault. If the whole house backs up, the main line is the more likely cause. Tell us what you notice and we will sort out which.
Standards and sources
These public references sit behind the rules and checks this page mentions.