Sewer backup clean-up in Toronto: why it is not an ordinary leak

A sewer backup is wastewater from the drain system coming back into the house, usually up a basement floor drain, toilet or shower. It is contaminated water. Do not wade in it or try to mop it, stop using water in the house, keep children and pets away, and get it extracted, the soaked materials removed and the structure disinfected and dried.

If the water came from a pipe or an appliance instead, start with the flooded basement guide.

How do you know it is a sewer backup?

If water is coming up through a floor drain, a basement toilet or a shower drain, it is a backup, whatever it looks like. Other signs are a sewage smell, cloudy or dark water and debris around the drain. A backup often follows heavy rain, when the sewers are carrying more than they were built for.

Groundwater from a failed sump pit or a leaking wall is not sewage, though it is not clean either. When there is doubt, we treat the water as the worse of the two.

Why is sewer water different from a clean water leak?

The restoration trade sorts water into three categories, and sewage is Category 3, the most contaminated. Clean water from a supply line is Category 1. The category, not the volume, decides what can be dried and kept, what has to be removed, and how the people doing the work protect themselves.

	Clean water leak	Sewer backup
Typical source	Supply pipe, water heater, appliance hose	Floor drain, basement toilet or shower
Carpet and underlay	Often dried in place if caught early	Removed and discarded
Drywall and insulation	Dried, or opened at the bottom	Removed where the water reached
What the work is	Extract and dry	Remove, clean, disinfect, then dry

Is it safe to clean up sewage yourself?

For anything beyond a small puddle on bare concrete, no. Sewage carries bacteria and other organisms that can cause illness, it soaks into porous materials you cannot clean, and the basement often holds the electrical panel and outlets near the floor. The City of Toronto suggests considering a professional cleaning company familiar with sewage contaminated basements.

If you have to go down, the City's list is full-length clothing, gloves, eye protection, rubber boots and a mask. Keep children and pets out until the area has been cleaned.

What should you do, and not do, in the first hours?

Make it safe, stop adding water, report it, and record it before anything moves. The City of Toronto advises contacting Toronto Hydro to have the power shut off if water is near outlets or the panel, and not using toilets and sinks unless absolutely necessary while a backup is suspected.

Do:

• Report the flooding to the City through 311, and call your insurer early.
• Photograph the water, the drain, the line on the walls and every damaged item.
• Call the 24 hour line on 647-697-7435.

Do not:

• Run the washing machine, the dishwasher, a shower or the toilet.
• Use a household vacuum or carpet cleaner on it.
• Throw out damaged belongings before they are photographed and listed.
• Run fans across it before it has been extracted.

What does professional sewer backup clean-up involve?

Extraction of the standing water, removal of everything porous it reached, cleaning and disinfecting what remains, and then drying. Drying comes last on a sewage job, because drying contaminated material in place leaves the contamination behind.

The work area is closed off with plastic sheeting. Carpet, underlay, baseboard, the lower drywall and wet insulation come out and are bagged. Concrete, tile and framing are washed and disinfected, and then dehumidifiers and air movers run until the readings show the structure is dry. Upholstered furniture, mattresses, cardboard and soft toys that sat in it are usually not worth keeping, and we say so plainly.

What does sewer backup clean-up cost?

AllCleaner's published water damage bands apply: a single small area is $1,500 to $3,500, a whole room flood is $4,000 to $7,500, and a full basement is $5,000 to $25,000. Sewage jobs tend to sit higher in their band than clean water jobs of the same size, because more material has to come out.

We look before we quote, and the price is confirmed before work starts. The cost of water damage restoration goes through the bands in more detail.

What should you document for the insurance claim?

Photographs before anything moves, a list of damaged items, receipts for emergency work, and a record of what was removed and why. Call your insurer early, and check your policy wording, because sewer backup cover is often an optional part of a home policy rather than a standard one.

We document the damage for an insurance claim as part of the work: the water at its height, the drain it came from, and the materials removed. We are not adjusters, and does home insurance cover water damage in Ontario explains the usual distinctions.

Does the City of Toronto help prevent the next one?

Yes, for eligible homes. The City's Basement Flooding Protection Subsidy Program pays up to 80 per cent of the invoiced cost of devices such as backwater valves and a sump pump, to a maximum of $6,650 per property at the time of writing.

It is open to registered owners of single-family homes, duplexes, triplexes and fourplexes. Conditions include disconnected downspouts, a contractor with a City of Toronto business licence, and a permit and inspection for a backwater valve. It pays toward prevention, not clean-up. The City's basement flooding page explains how to report flooding and how to submit a claim to the City.

Where we do this work

Sewer backup clean-up is part of our water damage cleaning and restoration service, and the emergency line is answered 24 hours. We work across Toronto, North York, Scarborough, Etobicoke, Vaughan, Mississauga, Markham, Richmond Hill and Brampton.