Mississauga’s Stormwater Charge for Homeowners: How the Rooftop Tiers Work, Who Qualifies for a Subsidy and How to Request a Review

A small line on the Region of Peel water bill, set by the size of your roof. Here is how the City sorts houses, condos and businesses, and what relief exists.

I’m Arthur Zhao, a Toronto real estate Broker. Picture a family in Mississauga with two listings open side by side: a semi-detached house and a mid-sized detached house a few streets apart. They have already lined up the mortgage payment, the property tax estimate and the hydro and gas history. One cost that never shows up in a listing is the City’s stormwater charge, and it is set by something a listing does not spell out: the footprint of the roof.

It is a small number. It is still worth understanding before you move in, because it is calculated differently for a house than for a condo, it arrives on a bill you might not expect, and there is a subsidy and a review process that some owners will want to know about. Below: what the charge pays for and who pays it, how houses are tiered, where it appears, the subsidy, and how a review works.

What the charge pays for, and which properties pay it

According to the City of Mississauga (2026), all properties in the city that drain into the City’s stormwater management system are subject to the charge. The logic is runoff: a property with more hard surface (roof, driveway, patio) sends more rainwater into the system. The City describes the money as a dedicated source of funding, used exclusively to deliver stormwater services and programs, keep the system in working order and set aside funds for future upgrades and repairs.

How your share is worked out depends on what kind of property you own. Houses are handled with the rooftop tiers in the next section. For residential buildings with multiple units (apartment buildings and condominiums) and for commercial and industrial buildings, the City measures the hard surface of the entire property, divides that total by one billing unit of 267 square metres, and multiplies the result by the current stormwater rate.

A building owned and operated by a condominium corporation receives one assessment. The City’s page says the condominium board or the property manager decides how that charge is divided among the individual unit owners, and that the board or property owner is responsible for administering and collecting the payments.

How houses are sorted into five rooftop tiers

For detached, semi-detached, freehold townhomes and row houses, the City does not trace every driveway and patio. It uses rooftop area as a predictor of total hard surface. The City’s explanation is that it studied a sample of residential properties, measured all their hard surfaces (rooftops, driveways, patios and others), and found rooftop area to be a reliable predictor of the total.

The five tiers, with the property types the City’s table lists beside each one and the annual fees the page shows as estimated for 2025 and 2026:

Smallest (rooftop 26.7 to 99 m²; freehold townhomes and row houses): $61.95 estimated for 2025, $64.45 estimated for 2026.
Small (99.1 to 151 m²; semi-detached, linked and small single detached homes): $86.73 for 2025, $90.23 for 2026.
Medium (151.1 to 194 m²; medium single detached homes): $123.90 for 2025, $128.90 for 2026.
Large (194.1 to 242 m²; large single detached homes): $148.68 for 2025, $154.68 for 2026.
Largest (242.1 m² and above; very large single detached homes): $210.63 for 2025, $219.13 for 2026.

The page says each house falls into a tier based on rooftop area; the property-type column is the City’s description of what sits in each band. The stormwater charge estimator on the City’s site shows the daily and annual charge for a specific address.

Back to the family comparing two houses. If the semi’s roof sits in the Small band and the detached house’s roof in the Medium band, the gap between the two estimated 2026 fees is $128.90 minus $90.23, or $38.67 a year. That is useful to know when you total up carrying costs. It is not, on its own, a reason to prefer one house over the other.

Which bill it shows up on, and why the amount moves

The stormwater charge is a City of Mississauga charge, but it does not appear on the property tax bill. The City’s page says it appears on your Region of Peel water bill.

The annual amount is converted into a daily rate. Each water bill shows the stormwater charge for the number of days since the previous bill, so the dollar figure can differ from one bill to the next even though your tier has not changed. To compare against the tier table, add up a full year of bills rather than reading a single one.

If you rent, the line rides on the water bill. The City’s page does not address tenants, so whether you pay it comes down to what your lease says about who pays water.

Relief for homeowners: the stormwater charge subsidy

For residential properties, the relief the City describes is a subsidy. According to the City’s page, low-income seniors and persons with disabilities may be eligible for a subsidy to help pay the stormwater charge, and anyone who qualifies for the City’s tax assistance for residents automatically qualifies for the stormwater subsidy. No separate application is needed.

So the practical question for a homeowner is not about the stormwater program at all; it is whether you qualify for the City’s residential tax rebate, which the City describes as available to seniors or people with disabilities with low incomes. I have not reproduced the income or age criteria here, because they sit on a separate City page and policy and can change. Check them directly with the City or through 311.

The City also runs a stormwater credit program, but it is open only to businesses (non-residential properties) and multi-residential properties that have put stormwater management best practices in place to reduce runoff.

Requesting a review of your assessment

If you believe the hard surface on your property was measured incorrectly, the City lets you request a review online. You look up your assessment on the stormwater estimator, give the street address and provide an email address. There is also a downloadable Request for Review Form that can be sent by email to stormwater@mississauga.ca, by mail to the City’s Transportation and Works, Environmental Services office at 300 City Centre Drive, Mississauga, Ontario L5B 3C9, or by fax to 905-615-3405.

What the review looks at: whether your rooftop or impervious area has been mapped accurately, using the most recent aerial imagery available to the City. Site visits are not part of the process, and results are sent by email.

What it does not look at: soil type; the ratio of hard surface to total lot area; proximity to creeks, rivers or ditches; and private stormwater measures such as disconnecting downspouts or using rain barrels. The City lists these as outside the assessment scope.

The City’s page also states that a review does not guarantee a lower charge: the charge may be raised, lowered or unchanged.

Houses versus condos, apartments and businesses

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