Your Sewer Backed Up. Here Is What Is Happening and What to Do.

Sewage is coming up through your bathtub, shower, floor drain, or toilet. You have a sewer backup inside your home.

Treat it as a health hazard. Sewage can carry bacteria such as E. coli, viruses such as hepatitis A, and parasites (Delaware Division of Public Health). Acting quickly limits the damage.

Step 1: Stop Using Water

• Do not flush toilets
• Do not run sinks, tubs, or showers
• Do not use the washing machine or dishwasher

Water sent down any drain has nowhere to go and adds to the backup. If someone might forget, turn off the main water supply, as Orange County's sewage spill guide suggests (H2OC).

Step 2: Keep People and Pets Away

Keep children and pets out of the area until cleanup is finished. Do not switch power on or off, or use electric tools or appliances, while standing in water. Open doors and windows to air the space out (CDC).

Step 3: Find Out Whether the Blockage Is Yours

Your home connects to the public sewer main through a pipe called the lateral. In general, the lateral is the property owner's job and the main is the public agency's:

• In unincorporated LA County and the cities its sewer maintenance districts serve, LA County Public Works says the owner is responsible for the entire lateral, including the part under the street (LA County Public Works).
• In the City of Los Angeles, LA Sanitation says owners must maintain and repair their entire private lateral (LA Sanitation).
• Orange County's property owner guide, developed with local sewer agencies, also puts the lateral on the owner, including sections under the sidewalk and street (H2OC).

Some cities split it differently (Riverside, for example, maintains the street portion), so check your city's rules (City of Riverside).

If you are not sure whether the problem is in your lateral or the public main, or sewage is spilling from a cleanout or manhole outdoors, call your city or sewer agency. In LA County's sewer maintenance districts, that is LA County Public Works at 1-800-675-4357 (LA County Public Works FAQ). In the City of Los Angeles, LA Sanitation's 24/7 Customer Care Center is 1-800-773-2489. Elsewhere, call your city's public works department or local sewer district. If the public main is flowing, the blockage is in your lateral and you need a licensed plumber.

Step 4: Find the Cleanout, but Leave the Cap On

A cleanout is an access point to the lateral. It usually looks like the end of a pipe with a cap on it, often within a few feet of the house (City of Carlsbad). Some homes also have one near the property line.

Do not take the cap off to relieve the backup. Carlsbad's sewer page warns that doing so causes a sewer spill and is a health violation. When the plumber opens it, keep everyone back, because a backed-up line can spill as soon as the cap comes off.

Step 5: Hire a Licensed Plumber With Main Line Equipment

You need a plumber with a power auger (a motorized cable machine for the main line) and ideally a sewer camera. Look up the contractor's license on the CSLB website before work starts. CSLB also suggests getting a written contract and not paying far ahead of the work (CSLB tips).

What Causes Sewer Backups

Tree roots and grease. In the City of Los Angeles, LA Sanitation says tree roots and poured fats, oils, and grease cause more than half of sewer backups (LA Sanitation). Roots seek moisture and grow into laterals through cracks and breaks. Grease sticks to pipe walls and hardens, and running hot water after it does not help (LA County Public Works). Sagging or collapsed pipe. Old lines can sag or collapse. Sewage collects in the low spot or cannot get past the break. Wipes and other items. Wipes (even ones labeled "flushable"), paper towels, diapers, and sanitary products do not break down in the sewer line (San Bernardino County Special Districts, LA County Public Works). Flush only toilet paper.

Typical Cost to Fix a Sewer Backup

These are typical estimated ranges for licensed plumbers in LA and Orange County, not quotes.

Repair	Typical estimated range
Snaking the main line (cleanout to street)	$200 to $450
Hydro jetting the main sewer line	$500 to $900
Sewer camera inspection	$150 to $350
Spot repair of a damaged section (5 to 10 feet, excavated)	$1,500 to $4,000
Full lateral replacement (trench or trenchless)	$5,000 to $15,000
Trenchless pipe bursting	$6,000 to $12,000
Emergency surcharge for a backup into the home	Adds $75 to $150

Sewer line replacement requires a permit and inspection, and work in the street may need a separate permit (City of Torrance).

Cleaning Up Safely

The CDC's guidance for cleaning up sewage (cleanup guidelines, cleanup tips):

• Wear rubber boots, rubber gloves, and goggles, and cover any cuts with a waterproof bandage.
• Throw away anything you cannot clean or dry quickly, such as carpet, mattresses, and upholstered furniture. Remove drywall and insulation that sewage has soaked.
• Clean hard surfaces with hot water and laundry or dish detergent.
• If you use bleach, open doors and windows first, and never mix it with ammonia or any other cleaner.
• Wash with soap and water when you finish.

After the Line Is Cleared

Ask the plumber to run a camera through the line to see why it backed up.

Simple blockage: The line is clear. Focus on prevention. Roots: Cleaning removes them, but they can grow back through the same cracks. Your options are periodic cleaning or repairing or replacing the damaged pipe. Damaged pipe: A cracked, sagging, or collapsed section needs a spot repair or a full replacement. Trenchless methods avoid digging up the whole yard.

Preventing Another Backup

• Flush only toilet paper, and put cooled grease in the trash.
• Do not plant trees or large shrubs above or within several feet of your lateral (H2OC).
• If roots have been a problem, schedule periodic cleaning. The City of Carlsbad, for example, recommends professional cleaning once a year and a camera inspection every three to five years.
• Check whether you need a backwater valve. The California Plumbing Code requires one if any drain sits lower than the cover of the next upstream public sewer manhole (LA County Sanitation Districts). Installing one may need a permit, and upkeep is the owner's job: LACSD suggests a yearly inspection and says never to use the valve as a cleanout.

Not sure what you are looking at? Upload a photo to PlumberNearMe.ai for a free AI diagnosis and a typical cost range.

Sources

• Delaware Division of Public Health: Sewage FAQ (2023)
• H2OC: Sewage Spill Reference Guide for Private Property Owners
• CDC: Guidelines for Cleaning Safely After a Disaster
• CDC: Clean Up Safely After a Natural Disaster
• LA County Public Works: Sewer Maintenance Customer Information
• LA County Public Works: Sewer Maintenance FAQs
• LA Sanitation: Managing and Protecting LA's Underground Sewer System
• H2OC: Property Owner's Guide to Private Sewer Laterals
• City of Riverside: Home Sewer Line Maintenance brochure
• City of Carlsbad: Sewer information for property owners
• CSLB: What You Should Know Before You Hire a Contractor
• CSLB: Check a contractor license
• LA County Public Works: Sewer Maintenance Districts newsletter, 8th edition (2013)
• San Bernardino County Special Districts: Wipes flyer
• City of Torrance: Sewer Lateral Policy
• LA County Sanitation Districts: Backup Valves