That’s likely overly cautious. https://www.hammerpedia.com/frost-line-map/
That said, municipality’s will often be overly cautious and they do need to consider property siting abandoned.
That said, municipality’s will often be overly cautious and they do need to consider property siting abandoned.
I'm not in the country shown on your map. The area of Canada I'm in would be somewhere roughly around the 90" line on that map. It's between the 2000 and 2500 lines on this map [1] (the seasonal property is around a 1500 contour)
The municipalities pay for the main to be installed. They wouldn't spec it to be 8' (2.4m) deep if it didn't need to be.
edit: the contours in my source are not mm of freezing depth, but degree-days of freezing. However, 2500 DDOF corresponds[2] with 70" of frost penetration, while the 1500 DDOF corresponds with 55". So the required bury depths are slightly but not significantly conservative
[1] https://www.urecon.com/applications/images/canadian_map_lrg....
[2] 1962 source: https://nrc-publications.canada.ca/eng/view/ft/?id=15f6f5eb-...
I don’t know much about how Canada does things.