Multiple slow drains
Mention whether toilets, showers, tubs and sinks are affected. Several fixtures can share a restricted line.
Mesa Plumbing, Heating & Cooling · Local since 1982
Is Your Main Sewer Line Clogged? Signs & Next Steps
Several drains backing up together can point to a shared drain or main sewer restriction. One slow fixture may have a smaller, local blockage. Neither symptom alone proves that the sewer pipe needs replacement.
Licensed & insured · Veteran owned & operated · Boulder County & nearby communities
At a glance
The short answer
Several drains backing up together can point to a shared drain or main sewer restriction. One slow fixture may have a smaller, local blockage. Neither symptom alone proves that the sewer pipe needs replacement.
Boulder County homeowner guide
A guide for your next decision
By Mesa Plumbing, Heating & Cooling · Published November 12, 2026
This homeowner guide explains questions to ask. An on-site assessment establishes the cause, work and price for your property.
Understand the problem
One slow drain versus a main-line problem
Start with the pattern rather than guessing the cause. A bathroom sink that drains slowly while the shower and toilet work normally may have a restriction near that fixture. Water appearing in a low shower or floor drain when another fixture runs suggests a problem farther along a shared drainage route.
These observations help a plumber plan the visit, but they cannot locate a blockage by themselves. Tell Mesa which fixtures react together, when it started, and whether the problem has happened before.
Understand the problem
Signs worth reporting together
Wastewater at a low fixture
Water returning through a floor drain or tub deserves prompt attention. Stop using affected plumbing.
Gurgling or recurring odors
These can accompany drainage or venting problems. They are clues to investigate, rather than proof of a broken sewer.
If the main symptom is odor without a backup, read possible reasons for a sewer smell before assuming the underground line has failed.
Understand the problem
What to do when wastewater backs up
Stop using water at the affected fixtures and call for service. If several fixtures are involved, avoid running the dishwasher, laundry or additional taps while you arrange help. Keep people and pets away from wastewater and do not enter standing water near electrical equipment.
Do not repeatedly flush to test the line, open a backed-up cleanout, or add chemical drain cleaner. Tell the technician if any product has already been used. Cleanup and plumbing diagnosis may require separate help.
Understand the problem
How cleaning and inspection answer different questions
Drain cleaning aims to remove an obstruction. A sewer camera inspection looks at the accessible pipe interior and can help explain repeated trouble. A heavily blocked or submerged line may need clearing before a useful camera view is possible.
Ask what the technician can actually see, what remains uncertain, and whether locating the affected section is included. Hydro jetting may suit buildup in an appropriate pipe; it does not correct every structural defect.
Understand the problem
A clog does not automatically mean replacement
Roots, buildup, a damaged joint and poor slope can call for different solutions. Ask to see the findings before comparing a localized repair, pipe lining or sewer replacement. Ask how the proposed method addresses the observed cause and what it leaves unchanged.
For a larger proposal, use the sewer replacement scope checklist to compare access, preparation and restoration. An online symptom guide cannot establish the work or price for your property.
Understand the problem
Preparing for a Boulder County service call
Mesa serves Boulder, Longmont and surrounding communities. Share the address, affected fixtures, last normal use and any previous camera footage. Confirm coverage and current availability when you call; submitting a request does not reserve a time.
Keep learning
Related plumbing guides
When Should You Replace an Aging Water Heater? · Can Cold Weather Affect Your Plumbing in Boulder County? · All Mesa guides
Before you book
Questions homeowners ask
Can a main sewer clog affect only one bathroom?
It can, depending on the pipe layout and where the restriction is. A fixture-by-fixture symptom history helps, but diagnosis is needed to identify the affected line.
Will hydro jetting fix a broken sewer pipe?
No. Cleaning can remove suitable buildup, but a structural defect needs its own assessment and repair plan.
Should I keep running water to check the blockage?
No. If wastewater is returning through fixtures, stop using the affected plumbing and arrange service.
Let’s get it fixed
Tell us what is happening. We’ll help with the next step.
Call Mesa with your address, the symptoms and when the problem started. We’ll confirm service availability and help you arrange a visit. An online request is a request for contact, not a confirmed appointment.