Well Water Safety

Water Treatment Devices

Method

Uses

Limitations

Comments

Chlorination

Kills bacteria and viruses

Can be used to remove some forms of iron, as long as water is filtered after chlorination

Needs filtration to remove microbes shielded or embedded in dirt particles, including parasites

Needs careful handling of chlorine, testing of chlorine levels, and maintenance of dosing pump

Ultra-Violet

Kills bacteria and viruses

Needs filtration to remove microbes embedded in dirt particles, including parasites

Needs very fine (5 micron pre-filter), slow water flow, UV lamp must be kept clean

Filters

Use ceramic candle filters to remove bacteria and parasites, but not viruses

Use other filter types to remove sand, sediment, rust and particles

Use specially rated filters to remove very small particles

Need chlorination in addition to ceramic candle filters to remove viruses

Need regular maintenance and replacement for proper operation

Reverse Osmosis

Removes nitrates, sulphates, hardness, most microbes, dirt particles and small amounts of some pesticides

Can result in plugged membranes due to hard water

Is costly because of need to replace membrane

Needs pre-filtration and softening of hard water

Ozonation

Kills most microbes, but not cryptosporidium

Removes organic compounds, including pesticides

Can be used in combination with activated carbon filters

Needs filtration to remove microbes embedded in dirt particles, including parasites

 

Varies in effectiveness depending on application and manufacturer

Activated Carbon Contactors

Remove small amounts of some chemicals

Used for removing tastes and odours, and reducing trace levels of organic chemicals (e.g., pesticides)

Are not suitable for removing minerals, or larger amounts of chemicals

Must be replaced regularly but hard to know when contactors are exhausted

Can become a dangerous source of bacteria, taste and odour problems

Distillation

Kills all microbes by heat

Removes heavy metals and nitrates

Often used in combination with activated carbon filters

Can remove only chemicals (e.g., fluoride, iron, nitrate) with a higher boiling point than water

Needs regular de-scaling and weekly disinfecting with bleach or heat

Can concentrate chemicals(with boiling points lower than water) in distilled water (e.g., ammonia)

Softeners

Reduce hardness that produces lime deposits on dish-washed items, and gives a starched effect on laundry

Need periodic replacement of softener salt and disposal of concentrated salty water

Needs periodic replacement of softener salt and disposal of concentrated salty water