Pickering Water Hardness & Quality Report (2026)

Pickering's drinking water is managed by the Region of Durham, drawing from Lake Ontario at the Pickering Water Treatment Plant (Ajax/Pickering lakeshore area). The distribution zone in Pickering incorporates a significant proportion of local Ordovician limestone groundwater in addition to Lake Ontario surface supply, producing water at 261 mg/L (15.2 gpg) — classified as very hard by Health Canada, with a TDS of 710 mg/L reflecting the deep dolostone aquifer contribution. All supply is treated and meets Guidelines for Canadian Drinking Water Quality (GCDWQ) standards.

Pickering's distribution zone sits above Ordovician Trenton Group limestone and dolostone — highly productive carbonate aquifers that underlie the Ajax–Pickering–Whitby corridor. Groundwater from these formations is very hard and calcium-sulphate rich, producing a significantly higher hardness and TDS than Lake Ontario surface water alone. The blend of Lake Ontario supply and deep Ordovician aquifer groundwater in Pickering's distribution system accounts for the very high 261 mg/L hardness — consistent with the Whitby and Ajax zones in the same regional supply area.

At 261 mg/L, Pickering homeowners face aggressive scale build-up on kettle elements, showerheads, and in hot water tanks — descaling every one to two weeks is common. Hot water tank elements accumulate heavy scale deposits within one year; annual inspection, descaling, and flushing are strongly recommended. A whole-home ion-exchange water softener is considered essential for protecting appliances and plumbing in Pickering — the very high hardness makes softener installation a cost-effective investment for any household seeking to reduce maintenance costs and extend appliance lifespan.