WC148 MayJune 2026 - Magazine - Page 30
WATER MANAGEMENT
From Permits to Policy
What Ontario’s open water data reveals about
water use, groundwater, and future policy
BY SIMA SAADI AND CAROLYN JOHNS
N ONTARIO, most water takings above 50,000
litres a day require a Permit to Take Water under the
Ontario Water Resources Act. Over the past decade
Ontario, like many jurisdictions, has moved to making water data open and publicly accessible. This
includes Ontario’s open Permit to Take Water (PTTW)
and Reported Water Use (RWU) datasets which provide
researchers with a window into Ontario’s water use system: who is authorized to take water, and what permit
holders report using. The increasing availability of open
water data presents opportunities for new research and
exploration that can offer useful insights such as, where
water demand is concentrated, which sectors depend on
permitted water, how patterns have changed over time,
and where more policy attention is needed.
Drawing on PTTW data from 1960 to 2022 and RWU
data from 2020, the most recent datasets available when
we conducted the analysis, our research recently published
in Canadian Water Resources Journal, asked several basis
research questions. Who holds water permits in Ontario?
Where? Which sectors rely on surface and groundwater?
What can the data tell us about the relationship between
permitted and actual reported use? And, what broader
lessons does analysis of open data offer for water governance
and policy in Ontario and beyond?
however, permit activity has risen much more consistently, with
some notable peaks around 2005 and 2015. Open data cannot
explain every driver of increasing number of permits being issued
on its own, but the pattern clearly links water permitting to
broader shifts in development, population, regulatory changes,
infrastructure expansion, and resource demand.
I
FIGURE 1. NUMBER OF WATER PERMITS BY ISSUED DATE, 1960-2022.
Mapped across the province, the pattern is clear: permits cluster
heavily in southern Ontario, especially around the Great Lakes
and the province’s main population and economic corridors, including Toronto, Hamilton, Niagara, Ottawa, and areas extending
toward the Quebec border. That concentration reflects where
people live, where agricultural and industrial activity is located,
and where municipal and development-related demand is highest.
What the historical permit record shows
Across the 1960 to 2022 period, Ontario issued 66,003
permits. At time of data collection in September 2023,
8,991 permits were active. This allows for time series and
trend analysis. Permit activity was modest in the earliest
years of the dataset, when the modern regulatory regime
was still taking shape. A sharp jump appears in the early
mid-1960s when permits started to be required, followed by
several decades of consistent annual issuance. Through the
1970s-1990s permit issuance incrementally increased but
was consistently below 500 permits annually. Since 2000,
Sima Saadi is the inaugural recipient of the
Geoffrey F. Bruce Postdoctoral Fellowship at
Toronto Metropolitan University.
Carolyn Johns is a Professor at Toronto Metropolitan
University in the Department of Politics and Public
Administration. She is also the Chair of the Geoffrey Bruce
Fellowships Program in Canadian Freshwater Policy.
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WATER C AN ADA • M AY/JUNE 2026
FIGURE 2. GEOSPATIAL DISTRIBUTION OF ONTARIO WATER PERMITS BY WATER
SOURCE TYPE, 1960-2022.
WAT E R C A N A D A . N E T
