This post by Gary the Water Guy discusses How to submit a water sample for bacteria testing?

The first step is completing the form
 your daytime telephone number
 the four-line detailed location, including postal code, of your water source
 your public health unit number (see page 2 of water sample submission form)
 an indication of how you wish to receive your results
 the date the sample was collected
 a complete mailing address for results.
Note : Do not submit samples from high-risk water supplies, such as lakes, rivers or streams, unless water has been properly treated first. Consult your Water Stores Group store for treatment options.
Sampling your water for accurate results
1. Get a proper water sample bottle from the local public health unit. Only water collected directly into these bottles will be accepted.
2. Plan to sample your well water when you're sure you can deliver it to the public health unit within 24 hours. Remember that their cut off time is noon on Thursday so plan to submit it before then.
3. The best place to take a sample is from an inside tap with no aerator, such as the bathtub. Don't take a sample from an outside faucet or the garden hose.
4. Disinfect the end of the faucet spout with a dilute bleach solution (1 part household bleach to 10 parts water) before running water to remove debris or bacteria.
5. Turn on cold water and let it run for three to four minutes to remove standing water from your plumbing system.
6. Wash your hands with soap and water before proceeding.
7. Remove the sample bottle lid :
 don't touch the inside of the lid
 don't put the lid down
 don't rinse out the bottle.
8. Fill the bottle to the level that is marked, as described in the enclosed instructions, and close the lid firmly.
9. Fill the same name that is on the forms onto the sticker and stick to the side of the sample bottle being careful not to cover the bar codes.
10. Remove one of the bar code stickers and stick it onto the blue piece of paper and keep the blue paper so you can call in for the results 2 to 3 days after submitting your sample.
11. Return the completed information into the plastic bag and wrap around the bottle held in place with the rubber band.

12. Keep the sample cool (but not frozen) until it's returned to the drop-off location. Again, deliver the sample within 24 hours or it may not be processed. Remember that proper handling will help to make sure that your test results are accurate! Don't store samples in warm places such as your car trunk.
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