Category 3 water damage: what it means, and what to do about a sewage backup.

You may have seen “Category 3” on an estimate, or heard it from an adjuster or a restoration crew. Or you may just have sewage on your basement floor and want to know what to do. This guide covers both.

Our sources are the Kent County Health Department, the CDC, the EPA, Michigan’s insurance regulator and the City of Grand Rapids. Where they disagree with each other or with restoration companies, we say so.

What category 3 water damage means

The restoration industry sorts water into three categories by how contaminated it is. The categories come from a standard called IICRC S500. That standard is a paid document we have not read in full, so the descriptions here come from magicplan and Servpro, which quote it or similar guidance. Category 3 is described as grossly contaminated, able to contain “pathogenic, toxigenic or other harmful agents.”

Three things catch people out:

• Looks do not decide it. A toilet backflow from beyond the trap is category 3 regardless of visible content or color. Clear-looking water can still qualify because of where it came from. As a rough guide, the City of Ann Arbor says sewer backups are grayish and usually smell, while storm or snowmelt water is typically clear, but that is no test.
• Water can get worse. The category can change. magicplan, citing S500, lists contact with building materials, mixing with soil, elapsed time and heat as reasons. You will see companies say 48 hours, but the S500 wording we could read gives no fixed number. Treat it as “sooner is better,” not a countdown.
• Higher is not always right. Calling water a higher category than it is can mean unnecessary expense and disruption. Allied Public Adjusters adds that insurers may push back if the paperwork does not support it. Ask your contractor why they chose the category they did.

Sewage backing up right now? Do this first

1. Stay out of the water until the power is safe. Genoa Township, Michigan calls electrocution or explosion a greater danger than disease. The CDC says to turn off the main power only if you can reach it from a dry location. If you would have to step into water, call an electrician. Kent County says not to touch the fuse box, plugged-in cords or appliances until the power is off.
2. If you smell gas, leave. The CDC says to turn off the main gas valve if you can, open the windows and get out. Call the gas company or fire department, and do not do anything that could cause a spark.
3. Stop using all water. The sewerage district in Madison, Wisconsin, explains that anything you send down a drain goes into the backed-up pipe and comes out in the basement. That means no flushing, showers, dishwasher or laundry.
4. Keep people out. Kent County says to keep children, the elderly, people with weakened immune systems and pets away from the contaminated area.
5. Report it. Call your city or sewer utility so they can check the main. In Grand Rapids, call 311 or (616) 456-3000. If you are on a septic system, the EPA says to contact your local health department for guidance. The number on Kent County’s fact sheet is (616) 632-7100.
6. Take photos and video of the water line and everything it touched. Michigan’s regulator says not to get rid of damaged items until your insurer tells you to.
7. Call your insurer, and choose your words. The regulator says to report water damage and ask what coverage you have. Do not simply call it a flood, because a sewer backup may be treated differently.
8. Get the line cleared. The city normally clears a blocked main. If the main is fine, the blockage is likely in your own line, and you will need a plumber or sewer cleaner.

Can you clean up a sewage backup yourself?

Sometimes. You will get different answers on this. BELFOR, a national restoration company, says it is not safe. Public agencies are less absolute. Genoa Township recommends a professional restoration firm but gives steps for a small event, and Kent County’s health department publishes home cleanup steps too. We sell this service, so here is our honest line:

How to clean up a small backup

These steps come from Kent County’s fact sheet. It is dated 2013, and we checked it against current CDC and EPA pages. The steps agree, except on bleach strength.

1. Gear up. Rubber gloves, goggles and boots at all times. The CDC says to put a waterproof bandage on any cuts. Avoid tracking sewage into clean areas.
2. Remove the water. Drain or pump it out. Use shovels and a wet vacuum for soil and sewage, then clean and sanitize the tools. Only use electric equipment once an electrician has said the power is safe. Madison says extracted wastewater has to go into the sanitary sewer, once the drain is flowing again.
3. Remove what soaked it up. Bag carpet and padding, mattresses and upholstered furniture, and label them as contaminated with sewage. Photograph them first for your claim.
4. Wash everything it touched. Walls, floors and surfaces, using clean water and a low-suds detergent. Rinse with warm water. Have saturated drywall and insulation inspected to see if they need to come out.
5. Sanitize. Kent County says to rinse surfaces for 15 minutes with 8 tablespoons of chlorine bleach per gallon of water.
6. Dry it out. Open windows and run fans and dehumidifiers. Madison says not to use heat to dry closed spaces, and that fully drying can take weeks. The EPA says not to use the area until it has been completely dry for at least 24 hours.
7. Clean yourself up. Launder your clothes, and wash your hands and body with soap and warm water.

On bleach: agencies give different strengths. Kent County says 8 tablespoons per gallon, the EPA and Madison say about one part bleach to nine or ten parts water, and a CDC flood graphic says 1 cup per gallon. Follow the label, work with the windows open, and never mix cleaning products. Bleach also has limits. One utility warns that a bleach and water solution does not work in all situations, which is why soft, soaked materials go rather than get bleached.

What to do with your belongings

• Carpet and padding, mattresses, upholstered furniture: remove them. Bag or label them as contaminated.
• Clothes, blankets, sheets and towels: discard them unless washed and sanitized. Kent County says hot water, detergent and non-chlorine bleach, then clean the machine with 1 cup of chlorine bleach on a hot rinse.
• Pillows and stuffed animals: discard them.
• Food: throw away anything it touched, including food in paper, cardboard, screw caps or home-canned jars. Undamaged commercial cans and sealed pouches can be kept if scrubbed, then soaked for 15 minutes in 1 tablespoon of unscented bleach per gallon of safe water, and air dried. Relabel them.
• Well water: if your well flooded, do not use it until it has been tested. Kent County’s health department laboratory has sample bottles.

Is sewage dangerous?

Yes, in several ways. Kent County says sewage contains disease-causing organisms, and the EPA says to avoid contact because of harmful pathogens. One utility names dysentery, salmonellosis and hepatitis A. BELFOR adds E. coli, norovirus and rotavirus. If you get sick after a backup, tell your doctor you were exposed to sewage.

Is sewage smell in the house dangerous?

It can be, and it is worth taking seriously. The New York State Department of Health lists sewers and septic systems as sources of hydrogen sulfide, the gas with the rotten egg smell. It says that at low levels it can cause headaches and nausea, and that higher or longer exposure can bring more serious eye and breathing irritation, dizziness and vomiting. It may also worsen asthma. Most symptoms ease in fresh air or once the source is gone.

• Open windows to ventilate, as Washington’s health department advises.
• Do not trust your nose. Washington says that at extremely high levels you can temporarily lose your ability to smell the gas. It can also collect in low, enclosed, poorly ventilated spaces.
• Find the source. The EPA says a blocked or frozen vent can cause odors on a septic system, and that you should call a plumber or septic provider.
• If someone is dizzy or struggling to breathe, get them to fresh air and call 911.

What a professional cleanup involves

BELFOR describes the usual stages. The crew assesses how far the water went and seals off the area, using plastic barriers, protective gear and HEPA-filtered air machines. Then they remove the water and anything that cannot be saved, and apply disinfectant. Finally they dry the structure and repair it.

BELFOR says most cleanups take 3 to 7 days, while Allied Public Adjusters says a few days to several weeks. It depends on the size of the area and how much has to come out. Rebuilding comes on top of that. For costs, see our pricing guide and our Grand Rapids sewage cleanup page.

You may hear that the standard “requires” removing certain materials. That is a reasonable thing to ask about. Have the contractor show you what is wet, what they plan to remove and why, and make sure your adjuster sees it before it goes.

Does insurance cover category 3 water damage?

What matters is the source of the water, not the category. A sudden burst pipe may be covered even if the water became contaminated. A sewer backup or flood usually is not, without extra coverage.

• Sewer backup needs an add-on. Michigan’s regulator says endorsements offer limited coverage for water or sewer backup. Triple-I says most providers offer it for a nominal cost. Check whether you have it and what the limit is.
• Flood is separate. The regulator says flood damage is not covered under a standard homeowners policy.
• Your sewer line is yours. Triple-I says homeowners are responsible for the lateral, the pipe between the house and the city main, including any part under the street.

More detail is in our guide to what insurance covers when a basement floods.

If you live in Grand Rapids: 45 days

If you think the city’s sewer caused your backup, the City of Grand Rapids says sewer backup claims must be filed within 45 days of the backup or of when you first discovered it. Photos are required, and filing does not guarantee payment. The city’s Risk Management office is at (616) 456-4670. It also strongly encourages residents to carry insurance covering sewer overflows. Our Grand Rapids sewage page explains the rules and the city’s hardship program.

How to prevent the next one

• Install a backwater valve. It lets sewage out but not back in, and the CDC also suggests backflow valves. Use a qualified plumber. Madison says to inspect it at least twice a year, because these valves can stick open. In Grand Rapids, call 311 to ask about the city’s backwater valve program, as we could not confirm its current funding.
• Look after your lateral. Consider having it cleaned and inspected every few years. Tree roots, grease and sediment can plug it.
• Watch what goes down the drain. Triple-I names cooking grease, paper towels, wipes and feminine products.
• Check your connections. Triple-I says it is illegal to connect French drains and sump pumps to your sanitary sewer. See our guide to checking your sump pump.
• On a septic system, the EPA says to inspect it every 1 to 3 years and pump the tank every 3 to 5 years, or as needed.

Frequently Asked Questions