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Print | YORK REGION>Services>Water>Water Quality |
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Water Hardness in Treated Water | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Water & Wastewater | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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The concept of water "hardness" is typically used to refer to the ability of the water to make a lather from soap. Water is said to be "hard" if it is difficult to make soap suds. The two minerals that are most responsible for hardness are calcium and magnesium carbonate. Water hardness can also result in the scaling on pipes and appliances (hot water tanks, dishwashers). The following table gives an example of terms used to refer to relative water hardness and the corresponding range in chemical tests:
Relative Hardness Description Hardness Range (mg/L CaCO3) Grains/Imp. gallon Soft 0-60 0 – 4.2 Moderately Hard 61-120 4.2 – 8.4 Hard 121-180 8.4 – 12.6 Very Hard More than 180 More than 12.6 The average hardness in the water supplies in York Region is summarized in the following table: (equivalent grains per imperial gallon are also included in the table)
*Conversion factor from Hardness (mg/L) to Grains/Imp gallon: 0.07016
** Annual CaCO3 averages based on 2011 water sampling
The water in York Region is typically Hard to Very Hard. These results show that groundwater is typically "harder" than surface water. This occurs because the groundwater has travelled slowly through the sediments that are rich in calcium and magnesium which dissolve over time. This is typical of the majority of groundwater supply in all southern Ontario.
Surface water typically has a greater component of direct runoff from precipitation and therefore has less opportunity to dissolve high concentrations of minerals. Note that the water obtained from Lake Simcoe and Lake Ontario is also considered to be "hard" in terms of the relative scale provided above.
The degree of hardness that a person can tolerate is a matter of personal preference. The hardness of water is not known to have any specific health-related effects. Many people choose to install a water softener in their home to reduce the formation of scale in their water system and make washing easier. Water softeners work by exchanging the calcium and magnesium minerals with sodium or potassium (supplied in salts). In locations where softeners are installed it is recommended to maintain a separate unsoftened water supply for drinking.
Last Updated: February 2012 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
