Water quality, water hardness and water data
We take the responsibility of providing clean, safe water to Calgarians very seriously. Conversely, we must also ensure that the water returning to our rivers, via our stormwater or our wastewater, is equally clean and safe.
The City’s subject matter experts in Water Quality & Regulatory Assurance support all aspects of water within Calgary. Together we work to protect public health, infrastructure and our environment by monitoring, testing and tracking water quality data, trends and environmental performance. The City has four four externally accredited laboratories that maintain the ISO 17025 standard (through CALA) – providing confidence to Calgarians about the quality and safety of our water.
2019 | 2020 | 2021 | 2022 | 2023 | |
---|---|---|---|---|---|
Number of tests completed for drinking water line of service |
112489 | 112819 | 127136 | 142206 | 137456 |
Water hardness
Calgary's water is considered hard because of the amount of calcium and magnesium in the water from the Bow and Elbow Rivers.
What is water hardness?
Water hardness is caused by calcium and magnesium in the ground and surface water. These minerals come from rock such as limestone that dissolves in our river system. The results of having hard water can include difficulty making lather or suds while washing and/or a build-up of minerals on taps and other fixtures.
How hard is Calgary's water?
The hardness of Calgary's water varies seasonally and by location:
- The Bow and Elbow Rivers each have different hardness levels
- The lowest hardness levels are typically during spring snowmelt and the highest hardness levels are between December and February.
Generally, people in the northern half of the city receive water from the Bow River through the Bearspaw Water Treatment Plant. Residents in the south receive most of their water from the Elbow River through the Glenmore Water Treatment Plant.
Water Hardness, mg/L CaCO3
December to February | March to May | June to September | October to December | |
---|---|---|---|---|
Bearspaw range | 184-198 | 140-186 | 126-159 | 144-173 |
Glenmore range | 248-262 | 181-256 | 182-213 | 187-220 |
*ranges for 2023
Are there health issues with water hardness?
There are no known health effects associated with calcium and magnesium minerals in drinking water. However, conventional water softening systems (those that use salts) may not be suitable for people on sodium-reduced diets.
We recommend that consumers thoroughly research the various water softener systems available before deciding whether or not to soften their water.
For more information on water hardness please see the Canadian drinking water quality guidelines.
Water Quality Summaries
Treated Water from the Treatment Plants.
Key Drinking Water Quality Parameters 2023
Basic Water Chemistry
Water Quality Parameter | Units | Drinking Water Results | Limit | Major Source |
---|---|---|---|---|
Color | TCU | <2 |
≤15a |
Erosion of natural deposits in watershed. |
Hardness as CaCO3 |
mg/L | 126 - 262 | No limit | Erosion of natural deposits in watershed. |
pH | pH Units | 7.3 – 7.8 |
7.0-10.5b |
Influenced by the dissolved minerals in the water, temperature, and water treatment processes. |
Temperature | °C | 1.1 – 22.0 |
≤15°Ca |
River water temperature. |
Total dissolved solids | mg/L | 155 - 334 |
≤500a |
Erosion of natural deposits in watershed. |
Turbidity | NTU | <0.05 – 0.09 | <1.0 | Suspended particles in water. |
Inorganic Substances
Water Quality Parameter | Units | Drinking Water Results | Limit | Major Source |
---|---|---|---|---|
Aluminum | mg/L | 0.010 – 0.124 |
0.1b, c |
Water treatment process |
Arsenic | mg/L | <0.0005 | 0.01 | Erosion of natural deposits in watershed. |
Barium | mg/L | 0.026 – 0.083 | 2.0 | Erosion of natural deposits in watershed. |
Cadmium | mg/L | <0.0005 | 0.007 | Erosion of natural deposits in watershed. |
Calcium | mg/L | 32 - 69 | No limit | Erosion of natural deposits in watershed. |
Chlorine residual, free | mg/L | 0.85 – 1.33 | ≥0.2 | Plant treatment. |
Chromium | mg/L | <0.0005-0.006 | 0.05 | Erosion of natural deposits in watershed. |
Copper | mg/L | <0.0005 - 0.0006 |
≤ 2 ≤1a |
Erosion of natural deposits in watershed. Leaching may occur from plumbing (pipes and brass fittings). |
Fluoride | mg/L | 0.09 – 0.28 | 1.5 | Naturally occurring. |
Iron | mg/L | <0.010 – 0.017 |
≤0.3a |
Erosion of natural deposits in watershed. |
Lead | mg/L | <0.0005 | 0.005 | Erosion of natural deposits in watershed. Leaching may occur from plumbing (pipes, solders, and brass fittings). |
Magnesium | mg/L | 11 - 22 | No limit | Erosion of natural deposits in watershed. |
Manganese | mg/L | <0.0005 -0.0012 |
≤0.12 ≤0.02a |
Erosion of natural deposits in watershed. |
Mercury | mg/L | <0.0000019 | 0.001 | Erosion of natural deposits in watershed. |
Nickel | mg/L | <0.0005 -0.0006 | No limit | Erosion of natural deposits in watershed. Leaching may occur from plumbing (pipes, solders, and brass fittings) |
Nitrate as Nitrogen | mg/L | <0.005 – 0.19 | 10 | Erosion of natural deposits in watershed. |
Nitrite as Nitrogen | mg/L | <0.005 | 1 | Erosion of natural deposits in watershed. |
Potassium | mg/L | 0.4 - 1.1 | No limit | Erosion of natural deposits in watershed. |
Sodium | mg/L | 3.4 – 16.7 |
≤200a |
Erosion of natural deposits in watershed. |
Sulfate | mg/L | 43 – 92 |
≤500a |
Erosion of natural deposits in watershed. |
Zinc | mg/L | <0.0030 -0.017 |
≤5.0a |
Erosion of natural deposits in watershed. Leaching may occur from galvanized pipes, hot water tanks and brass fittings. |
Microbiological Parameters
Water Quality Parameter | Units | Drinking Water Results | Limit | Major Source |
---|---|---|---|---|
E. coli |
MPN/100 mL | <1 | 0 | Domestic animals, wildlife and human waste. |
Total Coliform | MPN/100 mL | <1 | 0 | Soil, domestic animals and wildlife. |
Limit specified by Guidelines for Canadian Drinking Water Quality (Health Canada Sept. 2022) or Alberta Government operating approval for aesthetic, health, and operational rationale.
TCU = True Colour Units.
NTU = Nephelometric Turbidity Units, a measure of water clarity.
MPN = Most-Probable Number.
mg/L = milligrams per litre, or parts per million (ppm)
(a) Aesthetic objective
(b) Limit based on annual average
(c) Operational guidance objective.
Drinking water data summaries
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