Who is responsible if buried construction debris is discovered on a property after I buy it in Ontario?

Buried construction debris, such as old foundation material, demolished building remnants, or fill containing waste, is generally the current owner's responsibility to address once discovered, consistent with Ontario's general approach that responsibility for a property's environmental condition follows current ownership rather than only the party who originally buried the material. This can include the cost of proper removal and disposal, and, if the debris has caused soil contamination or drainage problems, any related remediation.

Recovering these costs from a seller depends on whether the seller actually knew about the buried debris and whether it created a hazardous or otherwise seriously problematic condition that should have been disclosed; buried debris a seller genuinely didn't know existed, perhaps because it predates their own ownership, generally won't support a claim against that seller. Buyers who encounter unusual soil conditions, fill inconsistencies, or unexpected material while doing any excavation or landscaping work should document what's found, get a qualified opinion on whether it poses an environmental or structural concern, and avoid simply covering it back over, since improperly addressing buried debris can create its own compliance problems down the line.