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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.

Still looking for more information?

*External requests will require a Data sharing agreement. 

Have you checked out our open data?

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