Raccoons do use sewers, but they don't live there permanently

Raccoons travel through sewers regularly, especially in urban and suburban areas, but they don't nest or den in sewer pipes the way they do in attics or chimneys. A sewer is a transit route for them—a way to move between neighborhoods, find food, and access yards without crossing open ground. The pipes are dark, connected to multiple properties, and often lead to places where garbage sits. That makes sewers useful to a raccoon, but not a home.

What matters to you is that raccoons entering your sewer line can mean raccoons entering your home. If your sewer has cracks, loose joints, or a damaged section, a raccoon can squeeze through and end up in your basement, crawlspace, or even inside walls. This is less common than attic entry, but it happens—and it's harder to spot because you don't see the damage until the animal is already inside.

Key Takeaways

  • Raccoons use sewers as travel corridors and to hunt for food, not as permanent dens or nesting sites.
  • A cracked or deteriorated sewer line is an entry point into your home, especially in the basement or crawlspace.
  • Sewer entry is less common than roof or chimney entry, but it is harder to detect because the damage is underground.
  • A sewer camera inspection can show whether your line has gaps large enough for a raccoon to pass through.
  • One-way doors installed at the sewer cleanout can prevent raccoons from entering while allowing waste to flow out.

How raccoons move through sewer systems

Raccoons are excellent swimmers and climbers, and they navigate sewer pipes by following the flow of water and the smell of food. They enter through breaks in the line, at the junction where your sewer meets the main line, or through the cleanout—the access point in your yard where a plumber can snake the line or inspect it with a camera. A cleanout is usually a plastic or metal cap sitting a few inches above ground; if it's loose, cracked, or missing, a raccoon can lift it and drop down into the pipe.

Once inside, a raccoon will follow the line toward your house because that's where the food waste is. Grease, soap residue, and organic matter in household wastewater attract them. They may stop at a low point in the line to hunt for smaller animals or dig through debris, but they keep moving toward the source of the smell. If your sewer line has a break or a section of collapsed pipe, the raccoon can push through or widen the opening and enter your basement or the space under your house.

Signs that a raccoon may be using your sewer

You won't always know a raccoon is in your sewer until it causes a problem. However, a few signs suggest activity: a loose or missing cleanout cap, scratches or bite marks around the cap, or a foul smell coming from the cleanout area that's worse than normal sewer odor. If you notice water backing up into your basement, or if a plumber finds claw marks or fur inside the pipe during an inspection, a raccoon has likely been inside.

Raccoon droppings in your basement or crawlspace, especially near the sump pump or floor drain, are a strong indicator that the animal entered through the sewer. Raccoon feces are larger than rat droppings, often contain undigested food, and have a distinctive smell. If you find them, do not touch them—raccoon droppings can carry parasites and pathogens. Call a wildlife removal professional to inspect your sewer line and remove the animal.

What to do if you suspect sewer entry

Start by having a plumber or sewer specialist perform a sewer camera inspection. This involves feeding a small waterproof camera through your cleanout or a toilet, which sends video to a screen above ground. The camera shows cracks, breaks, tree root intrusion, and collapsed sections—all of which are entry points for raccoons. The inspection usually costs between $300 and $800, depending on the length of the line and your location, and it tells you exactly what you're dealing with.

If the inspection finds damage, you have two options: repair the sewer line itself, or install a one-way door at the cleanout to prevent raccoons from entering while allowing waste to flow out. A one-way door (also called an exclusion door) is a flapper or gate that opens outward only. The raccoon can exit but cannot re-enter. This is a temporary measure while you arrange for sewer repair, or a permanent solution if the damage is minor and the raccoon is the only problem. A plumber can install one in an hour or two.

Preventing raccoons from entering your sewer

Keep your cleanout cap in place and make sure it fits snugly. If the cap is cracked or missing, replace it when ready—this is the easiest entry point for a raccoon. You can also install a locking cleanout cover, which is heavier and harder for an animal to move. These cost $30 to $100 and are available from plumbing supply stores.

Reduce the smell of food waste in your sewer by running cold water after you use the garbage disposal, and avoid pouring grease down the drain—grease solidifies in the pipe and attracts animals. Keep your yard clean of fallen fruit, pet food, and garbage, which draw raccoons to your property in the first place. The fewer raccoons in your neighborhood, the fewer will be traveling through your sewer.

When to call a professional

If you find a raccoon in your basement or crawlspace, or if you suspect one is in your sewer, call a licensed wildlife removal company. Do not attempt to trap or corner the animal yourself. A professional can identify the entry point, remove the raccoon safely, and seal the opening. They can also coordinate with a plumber to repair the sewer line if that's the source of entry.

If a sewer camera inspection shows damage, a plumber should handle the repair. Sewer line repair ranges from spot patching (a few hundred dollars) to full replacement (several thousand), depending on the extent of the damage and whether the line is accessible. Your homeowner's insurance may cover some of the cost if the damage is from a covered cause, though most policies exclude animal damage. Check your policy or call your agent before you commit to repair.

Frequently Asked Questions

Can a raccoon actually fit through a sewer pipe?

Yes. A raccoon's body is flexible and can compress to fit through an opening as small as 3 to 4 inches in diameter. Most sewer pipes are 4 to 6 inches wide, so a determined raccoon can squeeze through if there's a break or loose joint. Larger breaks give them straightforward passage.

What's the difference between a sewer line and a septic tank?

A sewer line carries waste from your home to a municipal treatment plant. A septic tank is a private underground tank that holds and breaks down waste on your property. Raccoons can enter both, but septic tanks are less common in urban areas. The prevention methods are similar: keep access points sealed and have the system inspected regularly.

If I install a one-way door, will the raccoon get stuck inside my sewer?

No. A one-way door allows the raccoon to exit the sewer and move on to another area. It does not trap the animal. Once the raccoon leaves, you can remove the door or leave it in place to prevent re-entry while you arrange for sewer repair.

How often should I have my sewer line inspected?

Most plumbers recommend a sewer camera inspection every 3 to 5 years if your home is older than 40 years, or if you've had backups or slow drains. If you suspect animal activity, have it done right away. A routine inspection can catch damage before a raccoon uses it as an entry point.

Is sewer damage from a raccoon covered by homeowner's insurance?

Most homeowner's policies do not cover damage caused by animals, including raccoons. However, if the sewer line was already damaged and the raccoon straightforward used the existing break, you may have a claim for the underlying damage. Contact your insurance agent with details of the inspection findings.