Sewage Backing Up Into My House — Who Do I Call?

Right now

1. Stop using water. Every drain, every toilet, the washing machine, the dishwasher. Anything you send down adds to what comes up. Tell everyone in the house.
2. Keep people and pets out. Close the door to the affected area. Sewage is not dirty water; it carries bacteria, viruses, and parasites, and it aerosolises.
3. Cut power to the area at the breaker if sewage is near outlets, the furnace, or the water heater — but only if you can reach the panel without standing in it. If you can’t, call 911.
4. Photograph before you touch anything. Every room, every affected item, the water line on the wall. You will need this whether or not you have coverage.
5. Open windows. Ventilate. Don’t run the HVAC — you’ll distribute contamination through the ducts.

Call the city first. This is the part that saves money.

The instinct is to call a plumber. Call your city or county sewer department’s 24-hour line first.

If the blockage is in the public main, clearing it is the utility’s responsibility and their cost. Many utilities will send a crew to check even when it turns out to be on your side, at no charge. Calling a plumber first can mean paying a call-out plus a camera inspection to discover something the city would have told you for free.

Signs it may be the main rather than your lateral:

• Neighbours are affected at the same time
• Backup appears at the lowest fixtures — basement floor drain, ground-floor shower — with no individual fixture clogged
• It coincides with heavy rain
• Manholes on your street are overflowing or gurgling

Once the city confirms the main is clear, the problem is in your lateral, and now you call a plumber.

Which fixture is backing up tells you where the blockage is

Sewage comes out at the lowest available opening below the blockage, so the pattern of which fixtures are affected is a map of where the problem sits. Walk the house and note what backs up and what still drains normally.

One fixture, and nothing else — a single toilet, one sink, one shower → a local clog in that fixture’s trap or branch. This is not a sewer backup at all. A plunger, a hand auger, or a routine drain call handles it. Don’t call the city.

Everything in one bathroom, or everything on one side of the house → a branch line serving that group. A plumber, and still not the main.

The lowest fixtures in the house — basement floor drain, basement shower, a ground-floor toilet — while upstairs still drains fine → the blockage is downstream of everything, in your main line or your lateral. This is the textbook sewer backup.

A toilet gurgles, or water rises in it, when the washing machine drains or a bathtub empties → a partial main-line blockage pushing air back past itself. This is the early warning, and it usually arrives days or weeks before the flood. Getting a camera in at this stage is the cheapest version of this entire page.

Every drain in the house is slow at the same time → main line or lateral, and close to fully blocked.

Several neighbours affected at once, or manholes on the street surcharging → the public main. Call the utility and stop there. Nothing on your property will fix it.

The timing tells you what the permanent fix has to be, which matters because clearing the clog is not the same as solving the problem:

• Only during or just after heavy rain, then it clears on its own → the public system is surcharging, or groundwater is entering your line through cracks and bad joints. A backwater valve is the fix on your side; another drain cleaning is not.
• Slowly worse over months, then a backup → roots or a bellied section holding water. It will return on the same schedule until the pipe itself is dealt with.
• Suddenly, in dry weather, with no run-up → an object, grease, or a collapsed section.
• Only when the house is full of guests → a marginal line that fails at volume. Same underlying defect, just diagnosed later.
• On septic, worse after laundry day or a heavy-use weekend → a full tank or a saturated drain field, not a clog. Different trade entirely.

The call order, and what each wrong version costs

1. Stop using every drain in the house.
2. Your city or county sewer department’s 24-hour line. On septic, this step is a septic service instead — there is no main to check.
3. A plumber with a sewer camera, once the city confirms the main is clear.
4. Your insurer, before any demolition and before anything is thrown away.
5. A Category 3 certified restoration company, for anything porous that got wet.
6. The camera inspection and permanent fix, once it is clean and dry.

Each way of scrambling that order has its own price:

• Plumber before the city. You pay a call-out, and often a camera inspection, to establish something the utility checks for free — and if it turns out to be their main, you have paid to diagnose their repair.
• Restoration before the line is cleared. Equipment set in a room that is going to fill again. Most reputable crews will decline to start, so you have burned a day.
• Cleaning before photographing. Every argument you might have — with an insurer, a city, a landlord, an HOA — runs on those photos. Once it’s mopped, it’s your word.
• Demolition before the insurer has seen it. The same mistake, one order of magnitude larger.
• Waiting for an adjuster before removing sewage-soaked porous material. The opposite mistake, and just as costly. Contamination and mold don’t pause for a scheduling window. Document thoroughly, then mitigate.
• Pumping a septic tank again and again without establishing why it fills. You are buying the same day repeatedly at a few hundred dollars a time.
• Handling it yourself without protective equipment. This is the one that ends at a doctor rather than at an invoice.

Who will tell you this isn’t their job

Sewage crosses more trade boundaries than almost any other household emergency, and most of the frustration comes from calling the wrong one first.

• The city will decline your lateral. They check the main, and if it’s clear, they leave. That is the correct outcome and it cost you nothing — which is exactly why they’re the first call.
• A plumber will decline a septic system. “I called a plumber and he told me I need a septic company” is the single most common wasted call here. A plumber clears pipes; a full tank, failed baffle, or saturated drain field needs a septic contractor with a pump truck.
• A drain-cleaning outfit without a camera will decline the diagnosis. They will clear the blockage and leave, and they won’t tell you why it formed. If you want the cause, book the camera inspection explicitly — it is a separate service.
• A restoration company without Category 3 certification will decline sewage. Use the word “sewage” on the phone, not “water”. Hesitation on the other end is your answer; hang up and call the next one.
• A restoration company will also decline to start before the plumbing is fixed. Drying a room that is about to flood again is money set on fire, and a good crew will say so.
• A plumber will decline the cleanup. They clear the line and go. Contaminated carpet, drywall, subfloor, and insulation are a different trade with different equipment and different insurance.
• Carpet cleaners and general handymen will decline black water, and the ones who don’t are the ones to avoid. Category 3 water cannot be shampooed out of a porous material.
• Your landlord’s maintenance staff are not equipped for this. If you rent, treat it as a habitability issue rather than a maintenance ticket: report it in writing the same day, keep the photos, and escalate if nobody arrives.

The line that nobody knows they own

The pipe from your house to the sewer main is the lateral, and in the common arrangement, you own it. The utility maintains the main under the street; you maintain everything from your foundation to the connection.

Where exactly your responsibility ends varies significantly. Some cities take ownership of the portion under the public right-of-way and leave you only the part on your property. Others hold you responsible all the way to the main, including the section under the street — which is why a lateral replacement can involve permits, traffic control, and a bill several times what a homeowner expects.

Ask your utility where the line of responsibility is. Do it now, in writing if you can, not during a backup.

For what it’s worth in planning terms: Fixr puts clearing a main sewer line clog at $350 to $650 with a national average of $475; a camera inspection at $100 to $800; drain and sewer line repair at $400 to $1,500 typically and up to $5,000; and repairs under a slab at $500 to $4,500.

Treat it as a biohazard, because it is

Restoration professionals classify water in three categories. Sewage is Category 3, “black water” — presumed to contain pathogens. That classification is not a formality; it dictates what can be saved.

The working rule: non-porous surfaces can be cleaned and disinfected. Porous materials that absorbed sewage get removed and replaced. That means carpet and pad, drywall to a set height above the water line, insulation, particle board, upholstered furniture, and mattresses. Solid wood, tile, concrete, and metal are usually salvageable after proper cleaning.

If you handle any of it yourself: nitrile gloves, rubber boots, sealed eye protection, an N95 or better respirator, and long sleeves. Wash thoroughly afterwards. Do not let children into the space until it has been remediated and dried, and if anyone develops fever, vomiting, or diarrhoea in the following days, mention the exposure to a doctor.

The professional numbers, per Fixr: sewage backup remediation at $2,000 to $10,000 per project, Category 3 black water cleanup at $6.25 to $7.25 per square foot, and a Category 3 basement flood commonly landing at $10,000 to $15,000.

The insurance endorsement worth ten minutes of your time

Standard homeowners policies commonly exclude sewer and drain backup. The coverage exists, but as a separate endorsement you have to have bought.

Call your insurer today and ask two questions: Do I have sewer or water backup coverage, and what is the limit? Typical endorsement limits are modest relative to the numbers above, so ask whether a higher limit is available.

If the answer is no, you are paying for this event out of pocket — and the useful thing you can still do is add the endorsement before the next one. It cannot be applied retroactively, and backups repeat: the conditions that caused this one (roots, a bellied line, a surcharging main) are still there.

Stop it happening again

Once the immediate mess is dealt with, get a camera inspection before you accept “it’s cleared.” A clog that formed once formed for a reason — roots, a collapsed section, a sag holding water, grease, or a main that surcharges in storms. Fixr puts root removal at $100 to $600 and trenchless lining or pipe bursting at $50 to $250 per foot.

If the cause is the public main surcharging in heavy rain, the fix on your side is a backwater valve — a one-way gate on your lateral that closes when flow reverses. Many municipalities run rebate or cost-share programmes for installing one, precisely because it’s cheaper for everyone than the alternative. Ask your utility whether yours does.