Blue planet, green ideas | Tax impermeable surfaces

Torrential rains in record time, aging drainage systems: climate change is putting municipal infrastructure to the test. To fund them, more and more Ontario cities are imposing charges on asphalt and concrete surfaces, which prevent stormwater from being absorbed into the ground. A measure that arouses interest in Quebec, especially in Laval.

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

In the eyes of the general population, however, it is not the sexiest investment position. Since elected officials always have other priorities, funding this infrastructure from property tax revenues “simply does not work”, concluded Ontario’s Environmental Commissioner, Dianne Saxe, in a report published in 2016.

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 City spokesperson by email.

The stormwater runoff charge (stormwater charging) grossed 45.5 million in Mississauga last year. A quarter of the sum was used to finance the day-to-day management of rainwater, including work to curb the erosion of the banks. The rest (34.4 million) was transferred to a reserve fund.

This type of fee is part of the eco-fiscal measures envisaged in Laval, the municipality confirmed to us. “These measures could apply in certain sectors of the city where the mineralized areas are more important,” indicated a spokesperson for the City by email. Mineralized surfaces are in the line of fire 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 for [s’étendre] on the subject”, but tax measures could be announced “in the coming months”, affirmed 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 finance infrastructure to improve the management of runoff water.

On the surface of the customer

In Mississauga, the levy is invoiced to each property, according to the surfaces considered impermeable (roof, parking, etc.) that it comprises.

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

For single-family residences, Mississauga has created five flat rates tied to roof area. In 2022, the bill ranged from almost $60 (roofs under 100 m²) over $190 (over 242 m²).

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 impermeable 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 comprising 534 m² of impervious surfaces would have been subject to a $230 charge.

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.

Interest in Quebec

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 allows you to collect the most money and have 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 subsidy 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 cannot collect a tax on parking lots and a fee on impermeable surfaces because it is the same space, the same unit of assessment. So you have to know which is the most appropriate for the municipality. »