A new report says Canada is the only G7 nation that leaves unprepared homeowners on the hook financially for losses from severe flooding.

The study, released by Swiss Re Canada, said floods have made up half of Canada's natural disasters since 1970. The international wholesale insurance provider said flooding is expected to remain a major concern as such disasters become more frequent.

Christoph Oehy, of Swiss Re Canada, said residential homes in Canada are either totally vulnerable or only marginally protected from flooding losses. While insurance can be purchased for some water-related perils in Canada, comprehensive residential flood policies were not available until recently.

The way things are right now, Oehy said homeowners and government end up paying the majority of flood-related damage. It leaves many families without the necessary funds to rebuild their lives and delays economic recovery in the affected areas.

"We believe traditionally about 40 per cent of the flood risk each year is insured and about 60 per cent of the flood risk is uninsured," he said.

The report comes just days before the third anniversary of the 2013 southern Alberta floods, which forced 100,000 people from their homes, primarily in Calgary and High River, and caused an estimated $6 billion in damage.

The high water damaged 14,000 homes, 80 schools and 10 health facilities and forced the closure of nearly 1,000 kilometres of highway.

Calgary Mayor Naheed Nenshi, reacting to the report, agreed that the lack of flood insurance is a problem for many.

"It is very true that we have not yet solved the insurance issue in Canada on overland flooding, though a number of insurance companies are now offering overland flood insurance, which was never offered before," he said.

Nenshi advised Calgarians to check their insurance policies for overland flood coverage and to be ready for an emergency by having a 72-hour emergency kit prepared.

Comprehensive flood insurance lacking

The report said insurance covered only about one-third of the economic losses suffered as a result of the Alberta floods and about $1 billion of the almost $1.5 billion in total losses from a flood that submerged roads, railways and basements in Toronto a few weeks later that same year.

Swiss Re used a flood model to calculate the cost of one-in-200-year flood disasters province-by-province. The report

estimates a major disaster in Ontario could cost $6.4 billion in damages but only $2.5 billion would be covered. In Alberta, the projection would be $4.3 billion while only $1.8 billion would be insured.

Widespread flood insurance may not be far off but Oehy said it requires the co-operation of government, the insurance industry and homeowners. Four years ago, Oehy said there were questions about how to assess the risks without flood zones or models.

"That has definitely changed a lot and the flood in 2013 has certainly provided a lot of momentum to really get that work done."