Digging in Ontario: request a free locate first, and arrange private locates yourself

Deck footings, fence posts, a new downspout trench or an addition's foundation all start with a shovel or an auger. Hitting a gas line or a buried cable is dangerous and expensive, and in Ontario the law says the locate must come first. The common renovation failure is not skipping the call entirely, but assuming the free locate marked everything.

Who must call, and when

Ontario Dig Authority's homeowner page says anyone planting a tree, building a fence or deck, landscaping or doing a larger excavation must request a public utility locate before digging, on public or private property. Single-address projects need at least 5 business days' notice, and locates are to be completed within 5 business days. Multi-address or large projects need at least 10 business days' notice. The person doing the excavation should submit the request; if you hire a contractor, confirm that they have done it. The service is free.

What the free locate does not cover

Locators from each buried infrastructure owner mark their own lines. Lines that belong to the property are not marked by Ontario Dig Authority, and the property owner must arrange a private locate. The page lists examples: gas lines to barbecues or pool heaters, electrical lines to sheds, detached garages, lights or signs, sewer and septic systems, and telecom or electrical lines feeding security cameras. On renovation jobs these private lines are exactly what gets hit, because the house has grown over the years and nobody kept a drawing of the cable to the old garage.

Wait for every response

The page says to wait until all locate responses are received before digging. A locate package can include clearances from some owners and marks from others; starting when the first paint appears is how crews end up digging over a line from an owner whose response has not arrived. Follow the instructions in the complete locate package, and keep the markings visible while the work goes on.

When the plan changes

If the project changes, for example the deck grows or the trench moves, request a new locate. A locate covers the area that was described, not wherever the work ends up. On additions, ask the contractor to keep the locate sheets in the job file so the excavator, the foundation crew and the landscaper all work from the same papers.

Before clearing a blocked sewer

Ontario Dig Authority also warns that before clearing a blocked sewer with mechanical equipment, you should confirm that no natural gas line runs through the sewer pipe. Gas lines installed by boring can cross a sewer lateral, and a cutting tool can break them. The page offers a free sewer safety inspection request for this situation.

Prevention Checklist

• Submit the locate request at least 5 business days before digging (10 for large or multi-address work).
• If a contractor digs, ask for the locate ticket number before work starts.
• Arrange a private locate for lines you own: sheds, garages, barbecue or pool heater gas, cameras, septic.
• Do not dig until every owner has responded.
• Request a new locate if the dig area changes.
• Check for gas lines before mechanically clearing a sewer.

References

1. Ontario Dig Authority (formerly Ontario One Call). Homeowners, Web page, Legal requirement, notice periods, private lines, waiting for responses, new locate if project changes, sewer warning, free service. Accessed 2026-11-03.

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