The pipe in question is the sanitary sewer lateral: one pipe, usually 100 mm (4 inches), that carries everything from your toilets, sinks and floor drain out under the front yard to the main in the street. In older GTA neighbourhoods it is often clay or cast iron, and tree roots find the joints. When it blocks, water comes up at the lowest drain, usually the basement floor drain.
Is it the main line or just one drain?
If only one sink or toilet is slow, it is that fixture's own drain, which is private plumbing. If water rises in the basement floor drain when you run a tap or flush upstairs, or several fixtures gurgle at once, the lateral is blocked. Stop using water right away; every flush adds to what ends up on the basement floor.
Who do I call in my town?
Each municipality runs its own process, and some charge if the blockage turns out to be yours.
| Town | Call first | What happens | If the blockage is on your side |
|---|---|---|---|
| Toronto (incl. North York) | 311 | Toronto Water investigates, checks the street sewer and cameras the city side through your cleanout | You hire a licensed plumber; if there is no usable cleanout you may need one installed first |
| Newmarket | Town, 905-895-5193 (after hours, press 3) | The Town's contractor attends; you must first book a free sewer safety inspection through Ontario One Call | Your cost; the Town pays if evidence such as camera footage shows it caused the blockage |
| Aurora | Town, 905-727-1375 | The Town can flush and camera its sewer | The pipe to the property line is yours to maintain |
| Markham | Waterworks, 905-477-5530 (after hours 905-477-7000) | City staff investigate; only City staff may work on City property | You pay for inspection and repairs on private property |
| Richmond Hill | City, 905-771-8800, at any hour | The City sends its drain contractor after you sign a sewer servicing agreement | You pay a $754 call fee, with HST added, and hire your own plumber |
| Vaughan | A licensed plumber | The plumber books the Ontario One Call safety inspection; send the City any camera video | Your cost; if you call the City first, you pay a deposit of $744 on weekdays, refunded only if the fault is the City's |
Does the city pay if tree roots are in my sewer?
Only for the part it owns. Roots from a city tree can still block your side of the pipe, and each town treats that as the owner's problem. What matters is where the blockage sits, which is why a camera inspection that records the distance from the cleanout is the evidence towns ask for. Keep the video file and the plumber's written report.
What does a plumber do for a main line clog?
They clear it from the cleanout, usually in the basement near the front wall, with a sewer cable sized for a 100 mm line, then run a camera to find the cause and location. Toronto plumbing firms publish typical ranges of about $350 to $650 to cable a main line and $250 to $650 for a camera inspection. Replacing a collapsed private lateral is a different job, often several thousand dollars depending on depth, length and what sits on top.
On Doyo, drain cleaning is $259.60, the full price shown before you book, done by a 306A plumber Doyo has checked. If the plumber finds a main-line job that needs more, the new price has to be put to you in the order chat and agreed before it is charged.
Questions people ask
Sources
- City of Toronto — Blocked or backed-up basement drain · toronto.ca
- Town of Newmarket — Sewer blockage · newmarket.ca
- Town of Aurora — Basement flooding · aurora.ca
- City of Vaughan — Sewer backup · vaughan.ca
- City of Richmond Hill — Sewer backups · richmondhill.ca
- City of Markham — Basement flooding and sewer backup prevention · markham.ca
- City of Toronto — Basement Flooding Protection Subsidy Program · toronto.ca