Private Wells


 How well water gets contaminated
Your well water can be contaminated by:
  • openings in the well seal
  • improperly installed well casing
  • well casing not deep enough
  • well casing not sealed
  • a source of contamination not related to well construction (e.g. your septic system, pet waste or livestock waste, agricultural or road chemicals)
 Preventing Contamination
  • do not allow liquids or wastes from garbage and manure piles to drain towards the well casing
  • do not locate dog runs around the well casing
  • do not treat the area around the well with pesticides or fertilizer
  • do not flush oils, detergents, paints, solvents or other chemicals down the toilet

Proper installation and maintenance includes ensuring

  • sanitary seal or well cap is securely in place and watertight
  • cap is at least 30 cm above the ground
  • joints, cracks and connections in the well casing are sealed
  • surface drainage near the well is directed away from the well casing
  • surface water does not pond near the well
  • well pump and distribution systems are checked regularly
  • changes in the quantity and quality of water are investigated immediately
  • well water is tested for bacteria three times a year and after major plumbing work
  • wells are chlorinated and tested after any major repairs

Abandoned wells should be carefully sealed to prevent pollution of groundwater and any safety hazards. Hiring a qualified well contractor to seal the well is strongly recommended. 

 Other sources of drinking water
Bottled water

While bottled water available in Canada is generally of good quality, it is not necessarily safer or healthier than water from municipal supplies.

The sale of bottled water is not licensed in Canada. However, the federal Health Protection Branch makes spot checks from time to time of both domestic and foreign bottled water. In addition, local health units do regular bacterial testing on all bottled water distribution located in their district.

Municipal water supplies are checked for 350 or more substances. Only three substances must be checked in bottled water. These are bacteria content, fluoride and total dissolved solids (magnesium, iron, sodium).

Bottled water may contain naturally occurring bacteria, which under improper and/or prolonged storage conditions, could increase in numbers to levels that may be harmful to health. Refrigeration is a good way to reduce the growth of these bacteria.

Storage of bottled water may provide an opportunity for bacteria to grow, particularly if the containers were not sterile.

Water from cisterns

The water in cisterns usually comes from rainfall collected off the roof. It is stored in concrete tanks (reservoirs) in the basement or attic.

The water collected can be contaminated from many sources (especially bird droppings) and thus is not safe for drinking.

If a cistern supply exists or is planned, it is recommended that no connections be made between the main water supply and the cistern. Colour coding of the water pipes is also a good idea to ensure that a separation exists.

The use of a cistern supply is not recommended for human bathing or drinking water. Cistern water should only be used for such uses as lawn and garden watering and washing cars.

Sources of well water
There are over 50,000 private wells in the Ottawa area. Well owners are responsible for ensuring that water from their wells is safe to drink, and that their wells are not contaminating the groundwater. Wells must be properly designed and maintained to ensure that drinking water is safe.

Common types of wells: Dug and bored wells (with casings 60 to 120 cm/24 to 48 in.) are less expensive to install than drilled wells. Like sand point wells, dug/bored wells are prone to near-surface contamination and shortages. Drilled wells (casings 10 to 20 cm/4 to 8 in.) cost more but penetrate deeper aquifers.


Cross cut image of a dug well


Cross cut image of a drilled well

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