Last month I was asked to review an offer to purchase a $1.2 million waterfront cottage on Lake Simcoe. The experience underscored how important it is, especially in cottage transactions, to determine the exact size and location of the property being purchased with a land survey.

The would-be buyer was having trouble determining the size of the lot, and was concerned whether it was large enough to install a swimming pool between the cottage and the beach.

Back in 1972, a large parcel of land was subdivided into several hundred building lots, some of which — including this cottage property — were located on the waterfront. The plan of subdivision, which forever determines the lot size and location, showed the cottage lot dimensions as 50-by-150 feet.

The Geowarehouse database, used by many real estate agents, incorrectly gave the lot size as 50 feet wide by a depth of 218 feet on one side and 243 feet on the other.

Even more puzzling was a 1974 survey showing the cottage on a lot with depths of 203 feet on the north side, and 213 feet on the south side.

Understandably, my client sought my help to determine how much land he would be buying for $1.2 million.

I began by explaining that the current owner only had legal title to the original subdivision lot with a depth of 150 feet. Sometime in the past, it was clear that the front lawn had been extended many feet into Lake Simcoe, probably by artificial landfill. Everything between the original 1972 waterfront and the current shoreline was sitting on the bed of the lake, which is owned by the Ontario government.

The seller did not own, and could not legally sell, any land beyond the original 150-foot depth.

What I did not understand was how a 1974 survey could show a considerably larger property depth than what was shown on the original plan of subdivision. I turned to two experienced surveyors:

Sasa Krcmar, of Krcmar Surveyors Ltd. in Thornhill, and Derek Graham, of Graham Surveys in Elora.

Both suggested landfill, and that it would be necessary to check with the Lake Simcoe Region Conservation Authority to see if a landfill permit had been issued prior to 1974.

Krcmar noted that the shorelines of many of the cottages up and down the shore in the area of the cottage my client wanted to buy were generally consistent with the apparent depth of this lot. This, he said, would lead to the belief that the growth of the lots was either natural, “or everyone was in on the man-made (land) filling.”

If the expansion of a waterfront lot is caused by the ebb and flow of the lake, or by the lowering of the lake water level, then in some circumstances a cottage owner may be entitled to the “new” land — according to the legal principle of accretion.

In the final analysis, only an experienced professional surveyor can make a judgment call to determine the actual boundaries of a waterfront lot.

When my client realized that he probably would not get legal title to the larger lot size, he reluctantly backed out of the deal. This case offers an important lesson about buying waterfront property.