Water Quality Reports - Decew

The Decew Falls Water Treatment Plant provides water to St. Catharines and portion of Thorold, Lincoln and Niagara-on-the-Lake.

Current Status

The values below represent the water quality leaving the water treatment plant on the date indicated with the exception of pH which is for distribution water.

These values are updated on a monthly basis and measured by a laboratory that is certified by the Ministry of Environment, Conservation and Parks.

Parameter	Value	Sample Date	Range	Target in Range
Alkalinity	88 mg/L	April 13, 2026	30 - 500 mg/L	Safe and within our expected range
Hardness	123 mg/L	April 13, 2026	100 - 150 mg/L	Safe and within our expected range
pH	7.35	May 11, 2026	6.5-8.5	Safe and within our expected range
E. Coli	Not detected	May 4, 2026	0 counts/100 mL	Safe and within our expected range
Total Coliforms	Not detected	May 4, 2026	0 counts/100 mL	Safe and within our expected range
Lead	Not detected	Feb. 25, 2026	0-0.01 mg/L	Safe and within our expected range
Chloride	23.5 mg/L	April 13, 2026	0 - 250 mg/L	Safe and within our expected range
Sodium	17.4 mg/L	Feb. 25, 2026	0-20 mg/L	Safe and within our expected range
Sulphate	37.5 mg/L	April 13, 2026	0 - 500 mg/L	Safe and within our expected range
Fluoride	0.07 mg/L	April 13, 2026	0 - 1.5 mg/L	Safe and within our expected range
Vinyl Chloride	Not detected	Feb. 25, 2026	0-0.001 mg/L	Safe and within our expected range
Calcium	35.1 mg/L	April 13, 2026		No current standards or guidelines for this parameter
Magnesium	8.6 mg/L	April 13, 2026		No current standards or guidelines for this parameter

For more information about the quality of water in your local distribution system, contact your area municipality.

Reports

Under Ontario Regulation 170/03, Niagara Region and the area municipalities are responsible for providing water quality reports.

Water Quality Reports - Decew

Current Status

Reports

2025

2024

2023

2022

Water

Water Quality Reports