Everything depend son the municipality and province you live in. I can't speak for Halifax area, but on Lake of the Woods and surrounding unincorporated area, Ministry of Ontario is the governing body. Floating docks do not require a permit, but for the most part, you aren't allowed to modify the shoreline, except under direct permission from Ontario and/or the Department of Fisheries (Federal). You are allowed to build boat houses on land (with permits), or by driving pipe into the ground, as that minimizes damage to the shore.

The ministry will do periodic inspections of land, and will investigate complaints. The property we purchased had all vegetation removed from the shoreline to expose the natural sand beach. The owner was fined, and forced to lay down landscaping fabric and crushed granite to cover it in order to reduce erosion. The matter was strictly dealt with by Department of Fisheries.

As for septic, you're required to build a field, but permits are easily obtainable. Same goes with putting buildings; permits are (usually) required, but usually attainable relatively easily.