Guelph’s water supply

Guelph’s groundwater

Guelph is the largest Canadian city to rely almost exclusively on groundwater for its drinking water supply.

Groundwater comes from rain and melted snow that seeps into open spaces and cracks in soil and rock. Groundwater is found almost everywhere underground but there usually isn’t enough for an entire city’s water supply. Fortunately, Guelph is located above two aquifers which provide the city with high-quality water.
Guelph Aquifers

The aquifer is formed by limestone/dolomite bedrock formations extending across Southern Ontario between the Bruce Peninsula and Niagara Falls. These particular bedrock formations are good aquifers because they have large open spaces and cracks in some of the layers of rock. Wells drilled into this aquifer can provide sufficient water for individual houses, farms, businesses or for large municipalities like Guelph.

Most of Guelph’s water comes from a permeable zone called the “production zone”. In places, the bedrock is overlain by overburden deposits – clays, silts and sands placed by glaciers. Rain and snow filters through these formations before it reaches the bedrock. Some of these layers are aquitards—less permeable formations of clay or shale—which can act as barriers and protect deeper groundwater resources.

Naturally occurring fluoride

The City of Guelph does not add fluoride to our drinking water—we never have. Our groundwater sources contain low levels of naturally occurring fluoride well below standards set out in Ontario’s Safe Drinking Water Act. Detailed information about naturally occurring fluoride levels are included in Guelph’s annual water testing reports.

If you have questions about oral hygiene, or health-related questions about fluoride, please contact Wellington-Dufferin-Guelph Public Health.

Protecting our water

Under the Clean Water Act, there are 22 threats to our drinking water in Guelph; hazardous materials and chemicals and winter salting are the top two threats. When we use salt on our driveways and roads, and when we pour chemicals down the drain, we threaten the quality of our drinking water. Even a small amount of a chemical, like your pool water or the run-off from washing your car in the driveway, can contribute to a toxic level of contamination in our drinking water. It’s important that residents and businesses use chemicals and winter salt responsibly, and store these materials properly as well, to keep our groundwater safe.

Check out these rebate programs to learn how you can save water and money and learn how to dispose of hazardous materials and chemicals properly.

Municipal wells and water collection systems

Guelph has 21 operational groundwater wells and a shallow groundwater collector system called the Glen Collector System. The Glen Collector System is a series of underground perforated pipes that collect shallow groundwater from the Arkell Spring Grounds in the Township of Puslinch. Each year, between April and November, we pump water from the Eramosa River into an engineered infiltration pond and trench where it soaks into the ground to replenish groundwater supplies.

The water from the wells and collector system are treated and distributed to the community. The City supplies water to homes, businesses, fire hydrants and water storage facilities including our three water towers and our underground storage reservoirs.

Guelph’s water quality is excellent. The ground acts as a natural filter, and the City uses ultraviolet technology and chlorine as additional protection to ensure the safety of the water as it travels from the source to your tap.

Managing water services as our community grows

Guelph works with neighbouring communities to protect and preserve local groundwater resources.

Guelph’s water supply is a key consideration when the City reviews proposed development applications. Policies in Guelph’s Official Plan restrict or prohibit development where municipal water services may be insufficient.

Residential well owners

Well Aware is a guide to caring for your residential well.

As a private water well owner, it is your job to be well aware — to understand the basics of well maintenance and operation, and to take the necessary actions to keep your water wells in safe running order.

For more information visit

Get a rebate when you decommission your well and septic system

For more information

Water Services
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