Published: November 20, 2002
Last Revision: January 30, 2008
NOTE: For a printable copy of this information, download the brochure in Acrobat Reader format.
 Bacteria in my water supply?
Why Test?
How Often?
Bacteria Quality!
Where should I collect the water sample?
Testing for Bacteria in Your Water Supply
How do I collect a sample of water for
bacteria testing?
NOTICE ~ Bacteria Only Water Samples
Bacteria in my water supply?
The presence of bacteria such as coliform bacteria in drinking water would indicate the water is not safe for drinking and cooking. If you drink water which has coliform bacteria present, you could become ill. Pathogenic (disease causing) organisms present in water are capable of causing gastrointestinal disease.
Why Test?
- To determine the bacteria quality of your water for drinking and cooking.
- To ensure your water is free from harmful bacteria that could possibly cause disease.
How Often?
It is recommended that you have your water tested for bacterial quality every six months.
Bacteria Quality!
To check the bacterial quality of your water, it undergoes a presence/absence
test for
total coliform and E. coli.
Coliforms are a group of bacteria commonly found in soil and in the intestines of animals and humans.
The ABSENCE of either coliform or E. coli bacteria means that the water is suitable for drinking {PASSES}. The PRESENCE of either indicates that it is unsuitable {FAILS}.
Where should I collect the water sample?
The location for sampling should be the same location that you normally use to get your drinking water. In the majority of homes, this would be the kitchen cold water tap.
Taking water samples for bacteria analysis direct from the well is not recommended unless the proper sampling equipment is used. Simply lowering a bottle into a well on a string or using a dipper to collect the sample has a greater risk of becoming contaminated with bacteria and showing incorrect results.
TESTING FOR BACTERIA IN YOUR WATER SUPPLY
How do I collect a sample of water for bacteria testing?
A proper container must be used to collect the sample. These can be obtained from any Nova Scotia Department of Agriculture field office. The cost of the container and a presence/absence analysis is $12.82 + Disposal fee + HST. An MPN analysis (count) is available for $19.22 + Disposal fee + HST.
- To collect all samples, a sterile microbiological sample container, which contains 1-sodium thiosulphate pill (to neutralize chlorine) should be used.
- Sample containers should be kept clean and free from contamination before and after collecting the sample. They should not be opened prior to collecting the sample.
- At locations where the sample must be collected from a tap, inspect the outside of the faucet. If water leaks around the outside of the faucet, select a different sampling site. Remove any aerators, strainers, hose attachments, mixing type faucets, and purification devices from the tap.
NOTE: Sampling points will not normally be flamed. In some circumstances the tap can be flamed or disinfected at the sampler’s discretion.
- Run the cold water for at least three minutes before sample collection.
- Reduce the tap flow rate before taking the sample. The flow rate should be low enough to ensure that no splashing occurs as the container is filled. At sampling points where water runs continuously, do not adjust flow rate.
- Identify all containers and complete the corresponding requisition. All raw water samples are to be identified.
- While holding the sample container at the base, carefully flip the top cover up, (there will be some resistence), using the tab, hold the flip lid back from the water source. Be careful not to touch the edge, the underneath of the flip lid or the top and/or inside of the sample container. If the sample container is cracked or appears dirty or if you suspect there are any other conditions which places the quality of the container in doubt, it is to be rejected and replaced with another sample container.
Care is to be exercised to prevent breathing directly on the inside of the flip lid and also the container.
- The sample container is to be filled over the
"100 mL fill line", not under
which leaves enough air space in the container to allow
for mixing by shaking in the lab. The flip lid is carefully
replaced and the security string is inserted, this will
secure the tab and flip lid in place.
- Samples shall be transported to the laboratory within 24 hours. It is recommended that samples be kept at <10oC (in a refrigerator or cooler with ice packs) until delivered to the lab.
(Nova Scotia Department of Environment and Labour official guidelines, “Appendix A”. October 2000), amendments made for sample container.
If your water sample tests present for E. Coli, the lab will contact you directly (after 4:00 p.m. the following day) with your result.
If your water tests absent for E. Coli, you will receive notification by mail only. In this case, all precautionary measures need to continue until you receive your laboratory report indicating the status of total coliforms (which could be present or absent) in your report.
NOTICE
BACTERIA ONLY WATER SAMPLES
Laboratory Services will only accept water samples for bacteria analysis from Monday to Thursday. See Hours of Operation for specific times.
A cheque or money order made out to the Nova Scotia Department of Agriculture must accompany your sample. If you are mailing the sample, please address your package to the address below.
Sample drop-off location
176 College Road, Harlow Institute
Truro, NS B2N 2P3
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Priority analysis is available for a Rush fee which will be assessed when sample is received.
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For questions or comments, please contact: Laboratory Services
If you plan to drop off your sample see our Hours of Operation.
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