Flooded streets and residences, overflowing streams, the repercussions of saturated municipal drainage systems are not pretty to see.

In the eyes of the general population, however, it is not the sexiest investment position. With elected officials always having other priorities, funding this infrastructure out of property tax revenues “simply doesn’t work,” said Ontario’s Environmental Commissioner Dianne Saxe in a 2016 report.

At least eight municipalities in the province applied a charge on stormwater runoff at the time. The Ontario government should help others do the same, recommended the commissioner.

This is the model that Mississauga implemented in 2016. This suburban city of some 715,000 inhabitants southwest of Toronto manages more than 1,900 kilometers of storm sewers. “Several are aging and will need to be renewed or replaced in the medium or long term,” summarized a spokesperson for the City by email.

This type of fee is part of the eco-taxation measures planned in Laval, the municipality confirmed to us. “These measures could apply in certain areas of the city where the mineralized areas are more important,” said a spokesperson for the City by email. Mineralized surfaces are in the crosshairs because of their “significant impact on stormwater runoff” and their contribution to “the problem of overflows (discharge of untreated water into rivers)”. In addition, they create “significant heat islands”. It is “still early to [expand] on the subject”, but tax measures could be announced “in the coming months”, said Myriam Legault.

The City of Montreal is also considering adopting a tax on impermeable surfaces, including parking lots1. The measure, mentioned in a consultation document published in mid-March, would aim to fund infrastructure to improve stormwater management.

In Mississauga, the levy is charged to each property, depending on the surfaces considered impermeable (roof, parking, etc.) that it contains.

These so-called “hard” surfaces effectively prevent rainwater and snowmelt from penetrating directly into the ground. They therefore increase the pressure on municipal infrastructures.

For multi-unit buildings and non-residential buildings, which put more strain on the stormwater management system, the City applies a more precise calculation, which takes into account all the hard surfaces of the property. This total impervious area is divided into units of 267 m2, and the number of units is multiplied by an annual rate. At the 2022 rate ($113.40), the owner of a commercial building with 534 m2 of impervious surfaces would have been subject to a royalty of $230.

Many Ontario municipalities have implemented or are considering such a system. Toronto, Canada’s largest city, is holding a consultation in the spring to report back to council in July.

If no Quebec municipality has yet imitated Ontario, it is one of the ecofiscal measures that arouse the most interest among municipal managers, noted Professor Fanny Racicot-Tremblay, of ENAP, during his presentations.

“It’s one of those that raises the most money and has the best impact on the environment,” she explains.

Many municipalities that impose such a fee do in fact provide rebates for good practices.

Mississauga, for example, offers credits to owners of multi-unit and non-residential properties who invest in projects that limit runoff. These credits can erase up to 50% of the royalty.

In the United States, the City of Philadelphia has even created a dating app to connect owners of commercial and institutional buildings with environmental solution providers. Once the right partner has been found, owners can apply for a municipal grant covering up to 100% of the investment.

The interest of adding such a fee depends on the specific context of each city, however warns Professor Tremblay-Racicot. She gives the example of a municipality that would already tax parking spaces. “You can’t collect a parking tax and an impermeable surface charge because it’s the same space, the same unit of assessment. So you have to know which is the most appropriate for the municipality. »