The water quality problems described in this fact sheet may be resolved by use of a drinking water treatment unit. There are a wide variety of such devices available for home use. Health Canada works closely with NSF International to develop performance standards for water treatment devices. Consumers are encouraged to purchase products that have been certified to these standards.
If elimination of the source of contamination is not possible after shock chlorine disinfection, consider the installation of a batch or continuous disinfection system or a new water supply. Some suitable devices are described in Table 2.
Table 2: Household Drinking Water Disinfection Devices
|Water treatment method||Uses|
|Distillation||Kills all microorganisms.|
|Ultraviolet light||Kills bacteria and viruses. Use in conjunction with microfiltration to improve inactivation and remove particulate matter, including parasites.|
|Chlorination||Kills bacteria and viruses. Use in conjunction with microfiltration to improve inactivation and remove particulate matter, including parasites.|
|Ozonation||Kills harmful microorganisms. Use in conjunction with microfiltration to improve inactivation and remove particulate matter, including parasites.|
|Ceramic candle filtration||Removes parasites and bacteria. Use in conjunction with chlorination to remove viruses.|
Well water should also be tested for hazardous chemicals whenever contamination is suspected. Chemical analysis of water samples can be provided by commercial testing laboratories. Some provincial health laboratories will analyse water for nitrate, which typically originates from farming activities and seepage from septic tanks. High concentrations of nitrate may cause blue baby syndrome (methaemoglobinaemia), a condition in which methaemoglobin cannot release oxygen to body tissues, and which mostly affects infants under three months of age. Other chemical contaminants of concern include pesticides, heavy metals and volatile organic compounds. Guidelines for Canadian Drinking Water Quality provides a list of maximum acceptable concentrations for these chemicals. If hazardous chemical contaminants are detected, you should consider the installation of a treatment device or a new water supply. Some suitable units are listed in Table 3.
Table 3: Chemical Removal Devices
|Water treatment method||Uses|
|Activated carbon filtration*||Removes organic compounds, including pesticides.|
|Reverse osmosis*||Removes heavy metals and nitrates; often used in combination with activated carbon filters.|
|Distillation||Removes heavy metals and nitrates; often used in combination with activated carbon filters.|
|Ozonation||Removes organic compounds, including pesticides; often used in combination with activated carbon filters.|
* Should not be used with microbiologically unsafe waters or water of unknown microbiological quality.
Hardness, Taste, Odour and Colour
Well water contains naturally occurring minerals, such as calcium, iron and sulphur. Although these minerals are not hazardous to human health, they can alter the hardness, taste, odour or colour of the water when present in excess quantities. Groundwaters may also contain natural organic materials (tannins). Table 4 describes some signs that may indicate the presence of these substances in your well water and some solutions. In order to select the best treatment method, a full testing of the suite of minerals should be conducted prior to the purchase of a device.
Table 4: Common Aesthetic Water Quality Problems and Solutions
|Hard water (scales/deposits in kettles and water heaters)||Excess calcium||Water softeners*
|Rusty (red to brown) staining of fixtures and laundry and/or metallic taste||Excess iron||Chlorination-filtration
|Black staining of fixtures and laundry and/or metallic taste||Excess manganese||Chlorination-filtration
|Rotten egg smell||Hydrogen sulphide||
|Water has laxative effect||Excess sulphates||Reverse osmosis
|Turbidity/grittiness||Mud/silt/clay/sediment in water||Sediment filters|
|Organic (tea) colour||Tannins||Chlorination-filtration
* Individuals on sodium-restricted diets should consult their physician before drinking artificially softened water. Iron and manganese can also be removed by a softener, provided the water is not too hard.
Well Maintenance - Testing Well Water for Microbiological Contamination
Interpreting the Results of Testing
Corrective Action for Water that Does Not Meet the Recommended Guidelines
Water Treatment Devices for Home Use
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