Ontario One Call handles the notification for almost all of the buried infrastructure on public property (exceptions could include some first nations, provincial and federal entities.) This infrastructure is owned and maintained by organizations like public utility companies and runs through the public right of way and on to some private property up to a demarcation point, that varies from each utility owner. Public property lines differ per municipality, make sure to check your local rules.
All other buried infrastructure (including buried infrastructure beyond the demarcation point) on private property is the responsibility of the property owner to have marked.
Examples could include:
This image shows some examples of properties with public infrastructure shown in solid lines and private infrastructure shown in dashed lines.
To get your private lines marked, a competent private locator must be hired.