Sewer backup: what to do in the first hour

01 /What should you do in the first ten minutes of a sewer backup?

Your first job is to keep people safe and stop the backup getting worse. Property can be dealt with after that. If you want to tick the steps off as you go, the Sewer Backup Checklist follows the same order and records the time of each step for your insurer.

1. Keep out of the water if electricity is involved

   If water is near outlets, extension cords, the furnace, a water heater, a sump pump plug or the electrical panel, stay out of the area and call your electric utility or an electrician to cut the power. Only switch off basement circuits yourself if the panel is in a dry area you can reach without crossing wet floor, and you are confident doing it.

2. Stop all water use

   Tell everyone in the house to stop flushing, showering, running taps and appliances such as the washer and dishwasher. In a duplex or multi-unit building, tell your neighbours too; in a condo, tell the property manager. Wastewater from above drains down to the lowest opening, which is where the backup is.

3. Move people and pets away

   Children, pets, older adults, pregnant people and anyone with a weakened immune system should stay out of the affected area. Anyone who does go in should wear rubber boots and waterproof gloves.

4. Leave cleanouts and valves closed

   Do not open a cleanout cap while the line is under pressure; it will release sewage onto the floor and onto you. If you have a backwater valve, look at it only if you can reach it safely, and do not open it while water is standing above it.

5. Ventilate if safe

   Open windows if you can do so without entering contaminated water. Do not plug in fans or heaters in the wet area.

6. Shut off gas appliances only if safe and you know how

   If water has reached a gas furnace or water heater, contact your gas utility for advice. Do not relight any appliance that has been under water.

02 /Is it your line or the city's sewer?

Where the blockage is decides who you call. A blockage in your private building drain or lateral is your responsibility. A surcharged municipal main, often during heavy rain or snowmelt, can push sewage back into many homes at once.

If you suspect a municipal problem, call your city. In Calgary that is 311; many Canadian cities use 311 or a public works line. The city may check its main and the portion of the service connection it maintains. If the problem is on your side, you will need a private sewer cleaner, and you can request quotes through this network. The full list of causes, and how rain overloads city sewers, is in what causes sewer backup.

03 /What should you document for insurance before cleaning up?

Document before you clean, because photos taken after cleanup cannot show the extent of damage. Insurers generally expect you to prevent further damage, but they also need evidence of what happened.

• Take wide photos and video of each affected room, then close-ups of the water line on walls, flooring, furniture and stored items.
• Photograph the floor drain, the cleanout and any fixture where sewage came up.
• Note the date, time the backup started, which drains overflowed, the weather, and any calls you made, with names and times.
• Call your insurer or broker and record the claim number.
• Make a list of damaged items with approximate age and value; keep receipts where you have them.
• Keep damaged items, or photos of them, until your insurer says otherwise; some adjusters want to see samples of flooring or carpet.
• Save every invoice from the sewer cleaner, including camera findings that state the cause.

What the endorsement usually covers, how it differs from overland flood coverage, and how condo and tenant policies fit in are explained in sewer backup insurance.

04 /How do you protect your health during cleanup?

Sewage carries bacteria, viruses and parasites. The main exposure routes are hand-to-mouth, cuts in the skin and splashes to the eyes. Treat everything the water touched as contaminated until cleaned or discarded.

• Wear waterproof boots, heavy rubber gloves and eye protection. A disposable coverall helps for larger cleanups.
• Cover any cuts or scrapes before starting, and wash exposed skin promptly with soap and clean water.
• Do not eat, drink or smoke in the affected area.
• Do not mix cleaning chemicals. Bleach combined with ammonia or acid-based cleaners produces toxic gases.
• Wash work clothes separately in hot water.
• Seek medical advice if you develop fever, diarrhoea, vomiting or an infected wound after exposure.

The illnesses sewage can cause, what the smell means and when it is harmful are covered in is sewer backup dangerous?.

05 /What can be cleaned and what has to be thrown out?

Non-porous items can usually be cleaned and disinfected. Porous items that soaked up sewage are usually discarded, because contamination gets into the material itself. Health authorities in Canada, including Alberta Health Services, publish flood and sewage cleanup guidance; follow your provincial authority where it differs from this summary.

Dry the space quickly. Moisture left in framing, subfloor and concrete supports mould growth within days. Dehumidifiers, fans and open windows help once the electrical system has been confirmed safe. The full procedure, material by material, is in how to clean up after a sewer backup.

06 /What should the sewer cleaner do once the backup has stopped?

The sewer cleaner's job is to open the line, confirm it is open to the city connection, and tell you why it blocked. Ask for a camera run once the line is flowing. Without a cause, you are likely to repeat the whole experience.

Common causes of private-side backups include root intrusion, grease, wipes caught on a defect, and sags that collect solids. Each has a different fix, described in the main sewer line cleaning guide. For a step-by-step view of the visit, see what happens during a sewer cleaning visit.

07 /How do you stop it from happening again?

Prevention after a backup has two parts: remove the cause in the pipe, and protect the house if the municipal system backs up.

1. Fix or schedule the private-side cause identified on camera: root control, grease habits, a repair at an offset joint, or scheduled cleaning of a sag.
2. Consider a backwater valve if you do not have one, and maintain it if you do. See backwater valve installation and the backwater valve maintenance guide.
3. Review your insurance for sewer backup coverage and its limits.
4. Keep valuables and important papers off basement floors, in raised or waterproof storage.
5. Set a maintenance interval with the Sewer Maintenance Planner and follow the preventive schedule.

Each of those layers, from keeping your lateral clear to managing downspouts and storm-day water use, is laid out in how to prevent sewer backups.

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