Correct Way to Take a Water Sample

  1. Wash your hands thoroughly with soap and water before you collect the water sample.
  2. Water sample bottles can be obtained from the listed Water Sample Bottle Pick-Up Locations. Unused water sample bottles can be kept as long as they have not been opened.
  3. DO NOT un-cap the sample bottle until you are ready to take the sample.
  4. DO NOT remove the white powder or rinse the bottle.
  5. Disconnect or by-pass all water treatment devices (e.g., water softeners and carbon filters). Consult the manufacturer’s instructions for the correct procedure.
  6. If possible, remove the aerator and washer from the end of the tap. Clean the end of the tap and threads with either a bleach and water solution or rubbing alcohol. If you are unable to remove the aerator from the end of the tap, submerge the end of the tap with a container filled with a bleach and water solution for ten minutes.
  7. Run the COLD WATER tap for five minutes.
  8. Unscrew the cap from the water sample bottle.  Be sure not to contaminate the inside of the cap or the neck of the sample bottle by touching these areas or placing the cap on the counter. If you accidentally touch the inside of the lid or the neck of the bottle it must be discarded and a new sample collected.
  9. Fill the bottle to the 200ml waterline and replace the cap.  Remember to re-install the aerator and washer on the tap and check for proper operation. Clean and disinfect the aerator prior to reattaching it to the tap.

  10. Complete the form provided by the Ministry of Health Provincial Laboratory (attached to bottle), including your telephone number with area code.  Water will not be tested if this form is not completely and accurately filled in.

  11. Water samples must be kept cold.  Keep the filled bottle refrigerated until you are ready to bring it to the appropriate drop-off location.  When ready, place the filled bottle in an insulated cooler with ice packs and transport to the nearest drop-off location.  Submit your water sample the same day that you obtain it or within 36 hours at the latest.  Late submissions (water more than 48 hours old) will not be tested.


  • Water samples are shipped to the Regional Public Health Lab in London from the St. Thomas Site on Tuesdays and Thursdays; Water Samples from the Woodstock Site are shipped Monday - Friday (note Friday cut-off is 11:00 am). Please check the different drop-off times at the various locations. Samples will not be accepted on Fridays or the last day before a long weekend.
  • The Lab will not test water samples containing high levels of chlorine. It is advisable to wait at least one (1) week if you have recently chlorinated your well.
  • Results of your drinking water samples may be picked up at the lab in London at 850 Highbury Avenue, 5th Floor, phone 519-455-9310. The lab will not fax sample results to you.
  • Visit the MOE list of Licensed Laboratories for testing of chemicals and particulates.

Public Health Ontario: Water Testing