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Private wells

Preventing contamination

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.

If your well water becomes contaminated,

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

Wells

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 dug well

Cross cut image of a drilled well

Cross cut image of a drilled well

Where water comes from

The water we drink generally comes from surface water (above ground) or groundwater (underground). Only about 1% of the Earth's water is surface and groundwater.

The water cycle: Rain or melting snow can take several paths. It can runoff into streams, lakes or rivers. It can seep into the ground to be used directly by plants or to recharge groundwater. It can evaporate and return to the atmosphere. The cycle is complete when water in the atmosphere returns to earth as rain or snow. Groundwater from a deep well may have been in the ground for hundreds or thousands of years. In a shallow aquifer, the water may be a few weeks or years old.

The hydrologic cycle

The Hydrologic Cycle showing how rain or snow runoff pools underground to provide water

The Hydrologic Cycle showing how rain or snow runoff pools underground to provide water

How water moves

Groundwater flows from areas of higher elevation and/or pressure to lower elevation and/or pressure. It can flow horizontally or vertically upward or downward but usually in just one direction. This direction of natural flow can be affected or changed by pumping a well. How fast groundwater moves depends on how porous the soil or rock is, and whether the groundwater surface is sloped. The speed of water movement varies greatly.

The water table: The point at which the ground is saturated determines the water table. This level rises and falls depending on rainfall and local water use. Taking water out of the ground faster than it is recharged by the water cycle will lower the local water table.

Contamination

Is it clean? When an aquifer gets contaminated, the water may be unfit and unsafe to use. Groundwater can become contaminated in several ways:

  • spills on the ground, e.g., fuel and pesticide spills
  • injection into the ground, e.g., septic leaching beds, disposal of waste in wells, contaminated surface water running into poorly constructed or maintained wells
  • improper handling of industrial solvents and chemicals
  • waste leakage, e.g., manure storage, wastewater, septic tanks and landfills
  • leaking underground and above-ground fuel storage tanks
  • groundwater travelling from contaminated to clean aquifers
  • over-application of manure, commercial fertilizers or pesticides

Whether the groundwater gets contaminated depends on:

  • the size or strength of the contamination source
  • the ease with which the contaminant can move into or travel through the soil
  • out how to protect your well from contamination.

Well information

Many residents rely on well systems for their drinking water. The City itself has five well systems and two purification plants to provide drinking water to residents

Find out how to get your well tested, how to prevent contamination and learn about common well problems and solutions. Learn about the City’s well systems and water purification plants and view their annual testing results.

Where water comes from

The water we drink generally comes from surface water (above ground) or groundwater (underground). Only about 1 per cent of the Earth's water is surface and groundwater.

The water cycle: Rain or melting snow can take several paths. It can runoff into streams, lakes or rivers. It can seep into the ground to be used directly by plants or to recharge groundwater. It can evaporate and return to the atmosphere. The cycle is complete when water in the atmosphere returns to earth as rain or snow. Groundwater from a deep well may have been in the ground for hundreds or thousands of years. In a shallow aquifer, the water may be a few weeks or years old.

The Hydrologic Cycle

The Hydrologic Cycle

How water moves

Groundwater flows from areas of higher elevation and/or pressure to lower elevation and/or pressure. It can flow horizontally or vertically upward or downward but usually in just one direction. This direction of natural flow can be affected or changed by pumping a well. How fast groundwater moves depends on how porous the soil or rock is, and whether the groundwater surface is sloped. The speed of water movement varies greatly.

The water table: The point at which the ground is saturated determines the water table. This level rises and falls depending on rainfall and local water use. Taking water out of the ground faster than it is recharged by the water cycle will lower the local water table.

Buying a Home? New Well

New wells must be designed carefully to protect our water resources. Wells must be drilled by a licensed water well contractor, who submits a water well record to the homeowner and the Ministry of the Environment.

Keep well documents safe, as you will need them when you sell your house. Be sure to ask for copies of these records when you are the buyer.

Contacts

Agency Services
City of Ottawa Public Health Tel.: 613-580-2400 Advice, information, sample bottles
Ontario Ministry of Health Laboratory 2380 St. Laurent Blvd. Tel.: 613-736-6800 Well water testing
Ontario Ministry of the Environment Tel.: 1-800-565-4923 Well records, information Tel.: 1-888-396-9355
Local water well drilling companies, consult the yellow pages Servicing, consultation
Ottawa Septic System Office managed by the Rideau Valley Conservation Authority (RVCA) Tel.: 613-692-3571 Septic system inspection

Well water problems and solutions

Common water quality problems, possible causes and treatments

Problem Possible Cause Treatment
Health effects: diarrhea, stomach cramps Bacteria, parasites, viruses
  1. Chlorination/filtration method
  2. Ultra-violet systems
  3. Chlorination - injector units
Methaemoglobinemia (blue baby syndrome) Nitrate Reverse-osmosis units
High blood pressure Sodium Reverse-osmosis units
Scale build-up in kettles and water heaters. Soap scum, bathtub ring. Hardness (hard water) Water softeners
Red to brown slime in toilet tanks; iron staining; unpleasant taste or odours Iron bacteria Chlorination/filtration units
Rusty black stains on fixtures, laundry Iron and/or manganese Filtration; greensand filters; water softeners; chlorination/filtration units
"Rotten-egg" smell and taste Hydrogen sulphide and/or sulphate reducing bacteria Chlorination/filtration units; greensand filters; aeration
Water has laxative effects Sulphate Reverse-osmosis units
Salty taste, corrosive Chloride Reverse-osmosis units
Gassy smell, gas bubbles escaping from water Gases (methane) Aeration; activated carbon filters
Cloudy water Turbidity (clay) Filters; alum treatment

East Ottawa – Champlain Groundwater Study