Drains Backing Up? How to Tell If It's the Main Line
Modern Perspective Plumbing, licensed plumbing contractor in Grover Beach, serving San Luis Obispo County
If one sink or tub is slow, it's probably a local clog. If several fixtures back up, or flushing a toilet makes a shower gurgle or back up, suspect the main line. Stop using water and call.
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What to do first
- Stop running water, flushing and using the washing machine or dishwasher.
- Notice which fixtures are affected, and whether it's the lowest drains first.
- Keep people and pets away from any sewage.
- Avoid pouring chemical drain cleaner into a drain that's backing up.
Call right away if
- Sewage is coming up in a tub, shower or floor drain
- More than one fixture is affected
- The same line backs up again within weeks of being cleared
We answer Monday–Friday 8AM–5PM. After hours, we take your details and call back first thing the next business morning, or Monday morning on weekends. No crew goes out overnight.
What usually causes it
- Local clog. Hair, grease or soap in one branch line usually affects one fixture.
- Main line blockage. Roots, grease or debris in the main line affect several fixtures, often lowest first.
- Damaged line. A low spot, offset joint or crack can keep catching waste, and a camera shows it.
Coming out to look is free, and you get the price before any work starts. Learn more about our drain cleaning.
Common questions
Why does my shower gurgle when I flush the toilet?
That often points to a blockage or a venting problem, so it's worth checking before it backs up.
Why does it back up during the first big rain?
Roots and cracks can let water into older sewer lines, and rain can push a marginal line over the edge.