DRINKING WATER

More and more people are beginning to realize the importance of a safe and wholesome drinking water supply. Modern technology has allowed man to tap into the abundant groundwater supplies of Ontario. Much of the water that is used by man is used for wastewater production as opposed to actual drinking water.

There are two fundamental types of water supplies used in Ontario, groundwater and surface water. To understand the benefits and risks of each type of supply, a brief explanation of each is included. First:

Surface Water

Relatively easy to access, surface water supplies are water bodies of water that are visible on the surface of the earth. Whether this type of supply is bucketed to the house or pumped via mechanical means, the water quality of surface water is generally poorer than groundwater supplies. Pollution is washed into surface water with rain and snow, and pollutants such as animal wastes, organic matter and spilled chemicals are flushed into these water bodies during spring melt or rain storms.

Once pollutants enter a water system, it is difficult to assess how much pollutant is present or how long it will remain. Bacteria, viruses, protozoa, and chemical contaminants all have the potential to affect human health. Understanding this, anyone who consumes surface water without some form of filtration and disinfection system is at risk of disease or illness.

Groundwater Supplies

Commonly referred to as an aquifer or water table, the water supply is contained in a porous sand or gravel layer beneath the earths crust. Groundwater supplies are divided into two broad categories, shallow and deep supplies. Shallow supplies are generally those water tables or aquifers which are less than than 6 meters (20í) from the surface, and deep supplies are any supplies beyond 6 meters.

Groundwater supplies are better protected against the pollution sources that affect surface water supplies. However, the proximity of the shallow groundwater table to industrial, agricultural or pollutant source makes these supplies more vulnerable than the deeper aquifer. Fertilizers or poorly operating septic systems in porous soils can leach pollutants which contaminate shallow aquifers.

To assess the water quality and level of contamination, there are two fundamental tests that can be performed. The first is a bacteriological test and the second is a chemical sample. The bacteriological test is simply a screening test for coliforms and fecal coliforms to determine if there is any bacteriological activity in the water supply. The chemical test is a more intensive screening of the water supply for multiple parameters (minerals, volatile organic compounds, pH, etc). The results are then compared to the water quality objectives set out in provincial or federal drinking water guidelines.

Most health units will provide bacteriological testing and sample interpretation, however chemical sampling of private supplies must be done through an accredited laboratory (See Water Testing Page).