Septic System Backup Into Your Home: What to Do

If your home is on a septic system, everything that goes down your drains flows to a tank in your yard and then out to a drain field (also called a leach field). When something goes wrong anywhere along that path, the wastewater has nowhere to go, so it comes back up into the house through the lowest drains: a basement floor drain, a basement toilet, a shower or a tub. Septic sewage is raw wastewater. The restoration industry's standard (IICRC S500) treats it as Category 3, "grossly contaminated" water, and it needs to be handled that way. Here's what to do. (Not sure if it's a backup or an overflow? See our guide to sewer backup vs. overflow. For general sewage steps, see our sewage backup guide.)

Septic sewage in your home right now? Call MaxClean Restoration at 732-539-2942 Open 24/7 in Monmouth, Ocean and Middlesex counties. We're usually on site in about an hour near Freehold, and in about 2 hours in Lacey, Stafford, Barnegat and Little Egg Harbor. If you can't be there, someone 18 or older needs to let our technicians in on the first visit.

Signs your septic system is backing up

• Toilets, tubs and sinks drain slowly, or several drains are slow at the same time
• Gurgling sounds in the drains or toilets, especially after flushing or running the washer
• Wastewater coming up through a basement floor drain, the lowest toilet, a shower or a tub
• Water coming up in one place when you run water somewhere else (like the washer making the shower back up)
• A sewage smell inside the house or outside near the tank or drain field
• Soggy ground, standing water or extra-green, fast-growing grass over the tank or drain field
• A high-water alarm going off, if your system has a pump tank or an alarm panel

Step by step: what to do right now

1. Stop using water in the house. No flushing, showers, laundry, dishwasher or running sinks. Every gallon you use has nowhere to go but back into your home. Tell everyone in the house, and turn off an irrigation system if it runs near the drain field.
2. Get people and pets away from the area. Keep kids, pets and anyone pregnant, older, or with a weak immune system or breathing problems out of the affected rooms.
3. Watch for electrical hazards. If wastewater is near outlets, cords, appliances or the electric panel, stay out and call your utility or an electrician. Only turn off a breaker if you can reach the panel without standing in water.
4. Don't touch the water with bare skin. If you have to go near it, wear rubber boots, waterproof gloves and eye protection, and wash up right after.
5. Take photos and video from a safe spot. Show the drain or fixture where the water came up, how high it got, and every room and item it reached. Take a few photos of the yard over the tank and drain field too.
6. Call a licensed septic service. They can find out whether the tank is full, a line is blocked, or the drain field has failed, and they can pump the tank if needed. Ask for a written report that names the cause.
7. Call a sewage cleanup company. MaxClean is an IICRC Certified Firm and handles Category 3 sewage cleanup 24/7: 732-539-2942.
8. Report the damage to your insurance company and write down the claim number.

What NOT to do

• Don't keep flushing or running water "to push it through." It makes the backup worse.
• Don't open the septic tank lid or lean into the tank. Septic tanks hold gases like hydrogen sulfide and methane that can knock a person out in seconds. Tank work is a job for the septic service.
• Don't drive, park or put heavy equipment on the drain field or over the tank. It can crush pipes and pack the soil down.
• Don't pour chemical drain cleaners, bleach or "septic additives" down the drains to fix it. They won't clear a full tank or a failed drain field, and some can harm the system.
• Don't use a household vacuum or shop vac on sewage unless it's set up for wet use, and never run fans in the area. Fans can spread contaminated droplets and odor through the house.
• Don't mix bleach with other cleaners. It can make toxic fumes.
• Don't try to save soaked carpet, pad or upholstered furniture by washing it. Porous items soaked with sewage usually can't be made safe again.
• Don't wait. Sewage soaks deeper into floors and walls the longer it sits, and wet materials can start growing mold in 24 to 48 hours.

Pumping vs. drain-field problems: what's the difference?

A septic backup usually comes from one of three places. Your septic service will figure out which one you have, but it helps to know the difference.

A key clue: if the backup comes back within days or weeks of pumping, the problem probably isn't just a full tank. Ask your septic service to check the drain field. A septic repair or replacement may need a permit; check with your local health department.

How sewage cleanup should be done

Septic sewage is Category 3 water, so cleanup is about removing contamination, not just drying. A proper job, following the IICRC S500 standard, includes:

• Protecting people: technicians wear protective suits, gloves, boots, eye protection and respirators.
• Containment: plastic barriers and air filtration keep contamination and odor from spreading to clean parts of the house.
• Removing the sewage: standing wastewater is pumped and extracted out.
• Removing what can't be cleaned: porous materials that sewage soaked into, like carpet and pad, drywall, insulation, and often baseboards and some wood trim, are cut out and thrown away. Soaked porous contents, like mattresses, upholstered furniture, stuffed toys and cardboard boxes, are usually discarded too. Food, medicine and cosmetics that touched sewage should be thrown out.
• Cleaning and disinfecting: hard surfaces like concrete, tile, framing and metal are cleaned first to remove the residue, then treated with an antimicrobial.
• Drying: dehumidifiers and air movers dry the structure, with moisture readings taken every day until the materials are back to normal.
• Checking the result: the area is inspected before rebuilding starts so contamination isn't sealed inside the walls.

Wait until the septic system is fixed, or at least pumped and working, before cleanup and drying start. Otherwise the next flush can undo the work.

Claim notes for a septic backup

• Document before cleanup starts. Photos and video of the water, the drain or fixture it came from, how high it got, and every room and item it reached.
• Get the septic service's written report that names the cause: a full tank, a blocked or broken line, roots, or a failed drain field. Keep the invoice too.
• Describe the cause as you know it, and say so if it isn't confirmed yet. A septic backup is a different event from a toilet or fixture overflow, and your insurance company reviews a claim based on what caused the damage. Our sewer backup vs. overflow guide explains why the difference matters.
• Check your policy and declarations page, and look for words like "water backup" or "sewer backup." Policies vary, and we can't tell you what yours covers. Talk to your insurance agent.
• Keep damaged items until they've been photographed and your adjuster says it's OK to throw them away, unless they're a health hazard. If something has to go right away, photograph it first.
• Keep your septic records, like past pumping receipts and inspection reports. Your insurance company may ask about the system's maintenance.

Working with your insurance

Our IICRC-certified technicians document the source and cause of the water with photos and moisture readings before and during the work, so your adjuster can see what happened.

We send the invoice to your insurance carrier on your behalf, but the invoice is still the homeowner's responsibility. That includes your deductible and anything your carrier doesn't pay.

In New Jersey, homeowners usually have the right to choose their own restoration contractor. We specialize in working with both homeowners and insurance companies to make sure the work is properly documented for your claim, so your home gets back to its pre-loss condition.

Learn more on our sewage cleanup page or our insurance claims page.

This guide is general information, not legal or insurance advice.

Printable checklist

Septic System Backup Into Your Home: Checklist

• ☐ Everyone stopped using water (no flushing, showers, laundry or dishwasher)
• ☐ Kids, pets and at-risk people kept away from the area
• ☐ Power off to wet areas (only if the panel is safe to reach)
• ☐ No bare-skin contact; boots, gloves and eye protection if you must go near it
• ☐ Photos and video of the water, source, rooms and yard
• ☐ Licensed septic service called; written report of the cause requested
• ☐ Septic tank lid left closed; nothing parked on the drain field
• ☐ Insurance claim reported and number written down
• ☐ Someone 18 or older ready to let technicians in on the first visit
• ☐ MaxClean Restoration 24/7: 732-539-2942

Frequently asked questions

Why is septic sewage coming up my basement drain? When the septic tank is full, the line to it is blocked, or the drain field can't absorb any more water, wastewater backs up toward the house and comes out of the lowest openings first, usually a basement floor drain, toilet, shower or tub.

Will pumping the septic tank fix the backup? If the tank was simply full, pumping usually fixes it. If the line is blocked or the drain field has failed, pumping only helps for a short time. If the backup comes back soon after pumping, ask your septic service to check the line and the drain field.

Can I use my water while I wait for the septic service? No. Stop all water use in the house, including flushing, showers, laundry and the dishwasher, until the septic service says the system is working again. Anything you send down the drains can come right back up.

Is septic backup water dangerous? Yes. Septic sewage is treated as Category 3, grossly contaminated water under the IICRC S500 standard. It can carry bacteria, viruses and parasites. Don't touch it with bare skin, keep kids and pets away, and leave the cleanup to trained technicians.

Can I clean up a septic backup myself? We don't recommend it. Sewage soaks into carpet, drywall and wood, and those materials usually have to be removed. Proper cleanup needs protective gear, containment, disinfection and drying with moisture readings, following the IICRC S500 standard.

Does homeowners insurance cover a septic backup? Policies vary. Check your policy and declarations page for words like "water backup" or "sewer backup," and talk to your insurance agent. We send the invoice to your insurance carrier on your behalf, but the invoice is still the homeowner's responsibility. That includes your deductible and anything your carrier doesn't pay.

What if I can't be home when you arrive? Someone 18 or older needs to let our technicians in on the first visit. We're usually on site in about an hour near Freehold, and in about 2 hours in Lacey, Stafford, Barnegat and Little Egg Harbor.

Need help right now? Call MaxClean Restoration at 732-539-2942 Open 24/7 in Monmouth, Ocean and Middlesex counties. We're usually on site in about an hour near Freehold, and in about 2 hours in Lacey, Stafford, Barnegat and Little Egg Harbor.

Related guides: Sewage backup in your home · Sewer backup vs. overflow · Flooded basement or sump pump failure · The insurance claim process, step by step · Found mold in your home · Sewage cleanup services · All guides

MaxClean Restoration, 11 Bannard Street, Freehold, NJ · IICRC Certified Firm · NJ HIC #13VH12188600 Open 24/7 across Monmouth, Ocean and Middlesex counties. Usually on site in about an hour near Freehold, and in about 2 hours in Lacey, Stafford, Barnegat and Little Egg Harbor.