Taking Well Water Samples

Bacterial testing of water

The Ministry of Health and Long-Term Care, through local public health units, provides free bacteriological water testing to Ontario residents who draw their drinking water from a private well. This service analyzes bacterial levels only. To analyze the water’s mineral or chemical content, contact a private laboratory.

When to take a well water sample

The bacterial stability of water cannot always be determined from a single sample. To establish sample drinking water quality, initially submit 3 samples at least one week apart. If the well shows acceptable coliform/E. coli counts, then sample 4 times a year. Do not send several samples at the same time.

Always test the well water if:

  • You install a new well
  • You notice any changes in colour, odour or taste of the water
  • You suspect a waterborne illness
  • The well has been flooded

How to take well water samples

  1. Obtain a free water-test bottle from the nearest Eastern Ontario Health Unit (EOHU) office. These bottles contain a special preservative to maintain the water until it’s tested. Do not rinse out the bottle before taking the sample.
  2. Before taking the water sample, wash your hands and avoid touching the rim of the bottle or the inside of the cap.
  3. When taking the first sample:
    1. Remove the screen or other attachments from the tap.
    2. Run the cold tap for 2 to 3 minutes.
    3. Disinfect the end of the faucet with an alcohol swab or dilute bleach solution (1 part household bleach to 10 parts water).
    4. Run the cold tap for 2 to 3 minutes more before collecting the sample.
    5. Fill the bottle to the line indicated.
    6. Fill out the laboratory requisition form found on the sample bottle. Make sure the form contains:
      1. Name and return address
      2. Location of the water source, including county identification and the civic number
      3. Date collected
      4. EOHU office number where water sample was collected
      5. The daytime telephone number of the person taking the water sample
      6. Indication of whether you will pick up the report at the Laboratory (see addresses on chart) or if you want the report mailed to you
  4. Refrigerate the bottled water sample until you are ready to leave. If it’s a really hot day, place your sample in a cooler during transportation. Bring it along with the completed laboratory requisition form the same day it was collected to the nearest EOHU office (see Well Water Sample Drop-Off Times). Water samples are then transported to a Public Health Laboratory. Avoid bringing in a sample during extremely cold spells because a frozen sample cannot be analyzed.

Test results

Test results are returned by mail or can be picked up at the laboratory. Only the person whose name appears on the Water Bacterial Analysis Form can pick up the results at the laboratory. If you want another person to pick them up, an appropriate release form must be filled. You can obtain these forms at the Public Health Laboratory (see addresses below), or at the nearest EOHU office.

You can also obtain your results by telephone by calling 1-877-723-3426, three business days after having brought the water sample to the EOHU office nearest you. The automated voice message system allows you to retrieve your results using the numbers from the bar code found on the bottle. See instructions on the blue card available with the Bacteriological Analysis of Drinking Water form.

Public Health Laboratory serving Cornwall:
181 Barrie Street
Kingston, ON K7L 3K2

Public Health Laboratory serving other areas in Eastern Ontario:
2380 St. Laurent Blvd.
Ottawa, ON K1G 5A4

For information on how to interpret test results, see How to Understand the Results of Your Well Water Tests.