Sewage Backup in the Basement: What Goes and What Stays

Why Sewage Is Not Ordinary Water

You go downstairs and the floor drain has come up. The water is brown, it smells, and it has reached the carpet in the den. Before you count buckets, ask where the water came from.

Water from a burst supply line starts out clean. Water from a drain or toilet does not. The CDC warns that "floodwater can contain dangerous bacteria from overflowing sewage", and that while skin contact by itself does not pose a serious health risk, eating or drinking anything contaminated with it can cause diseases (CDC, Guidelines for Cleaning Safely After a Disaster). The EPA puts it this way: "Flood water can bring microorganisms, including from sewage and other sources, inside buildings," and exposure during cleanup "can cause allergic or irritant effects, or in some cases even infectious diseases" (EPA, Flood Cleanup to Protect Indoor Air and Your Health).

Both pages are written for floods and natural disasters. We use them here because both name sewage directly, and because they are the public guidance a homeowner can read and check alone. The same logic decides your basement: what the water touched, and whether that material can be cleaned.

The First Hour

1. Get people and pets out of the area. The CDC's advice is to keep children and pets away from the affected area until cleanup has been completed.
2. Stop adding water. Stop flushing toilets and running sinks, the dishwasher or the washing machine until someone has found what is blocked.
3. Leave the HVAC off if it was hit. "If any part of your HVAC system was affected by the flood, do not use it to help dry out your house," says the EPA, which adds that cleaning and drying the system is best done by a professional.
4. Stay out of standing water near power. If water is near outlets, cords or a panel, do not wade in. Wait for someone who can make it safe.
5. Photograph everything before it moves. Angi's guidance is to "document damage with photos for insurance purposes before restoration begins" (Angi).
6. Call your insurer and a restoration company. Angi also advises contacting your insurance company before initiating repairs, because the carrier will want a restoration professional to assess the damage before deciding which repairs it covers.

If you have to go in, the CDC says to wear rubber boots, rubber gloves and goggles if sewage is involved. The order of the rest of the first day is in the first 4 hours after water damage.

The Rule: Does It Soak Up Water?

One test sorts almost everything in the room. The EPA's version: "You can usually clean and dry materials that do not soak up water. You should throw away materials that soak up a lot of water and can't be cleaned and dried" (EPA).

A glass jar sheds sewage. A carpet pad drinks it. Most decisions in a flooded basement come down to which of those two an item is closer to, and whether it can be cleaned and dried before mold has a chance. The EPA's mold guidance gives the target: "In most cases, mold will not grow if wet or damp items are dried within 24-48 hours" (EPA Mold Course, Chapter 4). The CDC's disaster guidance says the same thing in plainer words: clean up and dry your home quickly, within 24 to 48 hours if possible.

What Goes and What Stays

This table puts the CDC and EPA guidance in one place. The right-hand column says which page each line comes from, so you can read it yourself.

Sources: CDC, Guidelines for Cleaning Safely After a Disaster and EPA, Flood Cleanup to Protect Indoor Air and Your Health. The CDC's throw-away list reads "anything that you can't clean or dry quickly", so the test is whether an item can be cleaned and dried, not what it cost. The CDC also says to wash the clothes you wore for the cleanup in hot water and detergent, separately from uncontaminated clothes and linens.

The Judgment Calls

Some things sit between the two ends of the rule. Wood floors, built-in cabinets, subfloor and trim are the usual in-between items. The CDC lists flooring and molding among the surfaces to clean, but neither page says when a wood floor, a cabinet box or a subfloor that soaked up sewage can still be saved. That is a call someone makes after measuring.

Ask for the reasons behind each call. Ask for moisture readings on each of them, what the company plans to do and why, and what would change the plan. Mr. Fresh documents the damage with photos and moisture readings and works with your adjuster.

Walls need a second look even where they seem dry. The EPA's drying advice is to open inside doors and cabinets and remove drawers, shelves and built-in furniture such as cabinets "to allow hidden surfaces to dry" (EPA). If mold turns up behind a wall later, that is its own job, covered in mold behind drywall after a leak and on our mold remediation page.

Clean First, Then Disinfect, Then Dry

Order matters more than the product. The EPA's guidance runs in this sequence (EPA):

1. Clean gently with water and detergent. "First, you should use clean water and detergent to physically remove contaminants from surfaces." The EPA also says to avoid stirring up dust or scrubbing surfaces, and that "the first time you clean a surface, clean it gently to remove loose dirt and microorganisms."
2. Disinfect only clean surfaces. An EPA-registered disinfectant or sanitizer can be used on some clean surfaces that do not absorb water. "These products do not work on surfaces that have not been cleaned," and many are not intended for surfaces that absorb water, like fabrics or unfinished wood.
3. Never mix bleach with anything. The EPA says not to mix bleach with other chemicals such as ammonia or chemicals brought in by the flood water. The CDC says the same: never mix bleach with ammonia or any other cleaner.
4. Dry everything completely. Open doors and cabinets, and use fans, dehumidifiers or heaters if you have power. The EPA says to wait to start fans until you have gently cleaned any visible mold once, so the fans do not spread it.
5. Do not close up early. Do not seal wall cavities that were flooded, and do not paint or seal any wet surface "until you are sure the materials are completely dry on the inside."

On flooded houses the EPA is candid about time: "Drying can take a long time, usually several days to weeks." That is guidance for flood damage in general, not a schedule for your basement, so ask the company that measures it for an estimate in writing. More on how drying is judged is in how long water damage restoration takes.

Doing It Yourself or Calling Someone

The EPA calls flood cleanup "difficult and dangerous work" and says "it may be best to get help from experienced and qualified professionals if you can." It also says who should stay out of it altogether: people with breathing problems like asthma, people with weakened immune systems, children and pregnant people (EPA).

If you do it yourself, the EPA's gear list is an N-95 respirator, goggles without vent holes, gloves, pants, a long-sleeved shirt and boots or work shoes. The CDC adds rubber boots, rubber gloves and goggles where sewage is involved.

If you hire someone, the EPA's advice is to "ask about qualifications, training, and experience and check references." It also notes that the EPA has no certification program and keeps no list of flood cleanup contractors. One check you can run alone is the IICRC Global Locator, which connects homeowners with certified firms and technicians.

Mr. Fresh is a family-owned business that has served Solano County and the Bay Area since 2013, with IICRC-certified technicians and honest, upfront pricing with no surprise fees. It offers water damage restoration and emergency water extraction with 24/7 dispatch from Fairfield to Vacaville, Suisun City and the rest of the area. To compare companies on scope as well as price, read how Fairfield restoration companies compare.

Insurance: Check Before You Assume

Find out what your policy says about sewage before you assume either way. Triple-I, the Insurance Information Institute, says sewer backups "are not covered under a typical homeowners insurance policy, nor are they covered by flood insurance," and that the coverage has to be bought as a separate product or as an endorsement to a homeowners policy (Triple-I). Policies differ, so yours may read differently.

The California Department of Insurance tells consumers to read the exclusions in their insurance contract and to ask their agent or broker about available endorsements to extend coverage (CDI, Residential Insurance guide). Do that before anything is thrown out, and keep the photos you took in the first hour.

If there is a claim, California's Residential Property Insurance Bill of Rights says "a consumer is also entitled to select a licensed contractor or vendor to repair, replace, or rebuild damaged property covered by the insurance policy," and lists "an itemized, written scope of loss report prepared by the insurer or its adjuster within a reasonable time period" (California Insurance Code 10103.5). That is what the statute text says, not legal advice. Ask the adjuster how a contractor you pick will be paid, and get the answer in writing.

Whatever the policy says, keep a record of the loss: photos before cleanup, the written scope, the moisture readings and the receipts.

What It Costs Nationally

Angi's 2026 cost data says "contaminated water from sewage or flooding requires more extensive cleanup," and its per-square-foot averages rise with the type of water (Angi, water damage repair costs):

For basements, Angi says restoration costs "range from $500 to $1,500 for an inch of clean water from a burst pipe, up to $2,800 or more for two feet of sewage backup." Its national average for a water damage restoration job is $3,868, with most homeowners paying between $1,383 and $6,369.

These are Angi's national figures, not Mr. Fresh's price, and Angi publishes no Fairfield or Solano County row. A real number for your basement comes from someone who has seen it. For what moves the bill, see what drives water damage cost in Fairfield.

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