What are my legal obligations to properly decommission an old, unused well on my Ontario property?

An old, unused well left open or improperly capped is generally treated as a hazard and a compliance obligation for an Ontario property owner, since an abandoned well can act as a direct pathway for surface contaminants to reach groundwater, and can also pose a physical safety risk if it isn't properly secured. Ontario regulation governs how wells must be constructed and, when no longer in use, properly plugged and sealed by a qualified well technician using approved materials, rather than simply capped or left as-is.

Because well decommissioning done incorrectly can create ongoing environmental and liability exposure, this isn't a do-it-yourself project; it should be carried out by a licensed well contractor following the applicable technical requirements. If you're buying a rural property with a known old well on the land, whether abandoned decades ago or recently replaced by a newer well, ask directly whether it was ever properly decommissioned, and if not, budget for the work and treat it as a due diligence item before closing rather than an afterthought, since responsibility for an improperly decommissioned well generally follows the current owner of the land.