Sewer Backup: Causes, Fixes & When to Call a Plumber

What Causes Sewer Backup?

• Main sewer line blockage from grease, wipes, or debris
• Tree root intrusion into sewer pipes
• Collapsed or offset sewer line
• Heavy rain overwhelming municipal sewer system
• Improper items flushed (wipes, paper towels, hygiene products)

How to Fix Sewer Backup: Step-by-Step

1. 1
   Stop using all water and toilets immediately
2. 2
   Do not attempt to plunge — this can spread contamination
3. 3
   Keep people and pets away from affected areas
4. 4
   Turn off HVAC if sewage may have entered the air handler
5. 5
   Call a licensed plumber and your insurance company

Frequently Asked Questions About Sewer Backup

What causes a sewer line to back up?

The most common causes are: buildup of grease and non-flushable items, tree roots growing into the pipe, a collapsed or cracked sewer line, or heavy rain overwhelming shared municipal infrastructure.

Is a sewer backup covered by homeowner's insurance?

Standard policies typically exclude sewer backup unless you have a sewer backup rider (add-on). This coverage is inexpensive and highly recommended — a major backup cleanup and repair can cost $3,000–$20,000.

How do I prevent sewer backups?

Never flush wipes, paper towels, hygiene products, or grease. Have your sewer line camera-inspected every 3–5 years to catch root intrusion early. Consider a backwater valve to prevent municipal system backups from entering your home.

Related Plumbing Problems

• Slow Drain Slow drains indicate a partial blockage in the drain line and will worsen over time into a full clog.
• Sewer Gas Smell A sewage or rotten egg smell inside your home can indicate dried P-traps, cracked sewer vents, or sewer line damage.
• Clogged Toilet A clogged toilet that won't clear with plunging may have a blockage deeper in the drain or a foreign object lodged in the trap.