Treatment of Public Water Supplies

Treatment system requirements for public water are dependent upon the source of the water.  For example, treatment systems in northern Saskatchewan most commonly include filtration to 1 micron absolute and chlorine disinfection for a surface water source.

To ensure the treatment system is working adequately, appropriate testing equipment is required.  For example UV disinfection systems require an alarm that measures transmittance of UV and that warns the operator when the bulb needs to be replaced or sleeve needs to be cleaned.

If using chlorine disinfection a chlorine test kit for drinking water is required and daily monitoring of free and total chlorine needs to be conducted and recorded.  Testing should be done at the furthest point in the distribution system to ensure adequate treatment is reaching the furthest tap.

In order for any type of disinfection to be effective turbidity (a measure of organics in the water) must be ≤ 1NTU (Nephelometric Turbidity Unit).  This is often achieved through the use of filters.

Maintenance records are also requirement to show that the system is properly maintained in working order.

To ensure your treatment system is working as it should, testing equipment for the above-mentioned parameters is required.  Testing should be done twice daily and recorded. See example charts below.

Water Testing Records Chart (Monthly)

Maintenance Records Chart 

Minimum treatment requirements follow the 4-3-2-1-0 approach:

  • 4 log reduction in viruses;
  • 3 log reduction in cryptosporidium and giardia lamblia;
  • 2 treatment barriers minimum (example chlorine + filtration);
  • ≤ 1 NTU turbidity;
  • 0 total coliforms & fecal coliforms (bacteria)

Water quality should also meet the Canadian Drinking Water Quality Guidelines, which can be found here:

All new public water supply applicants need to submit initial bacteriological and chemical analysis to determine water treatment options, and to determine if the water meets the Canadian Drinking Water Quality Guidelines.