Sampling procedures

The accuracy and integrity of your results can be greatly influenced by sampling technique. Following these simple instructions will help ensure high quality results.  Please make sure you are using the appropriate bottles that correspond with the testing package you have chosen.


Sample bottles may be obtained from us at no charge.  If you are not sure what containers to use please contact the lab.  Typically our testing packages require 2 containers: 4-ounce sterile specimen cup and a 500ml plastic bottle.  Both of these containers must be filled.  Alternatively, you may procure a sterile specimen cup (like at the doctors office) from a local drug store for the bacteria analysis. It must be pre-sterilized as boiling bottles at home does not sterilize and increases the likelihood of a false positive. Bottles for chemical parameters may be any clean pint-sized container made of glass or plastic. If you are to test for volatile organics or radon you must get special vials from us.

Prior to sampling

When the sample is collected for bacteria or inorganic chemical parameters, sufficient air space (1/2 inch) should be left in the top of the bottle to facilitate shaking prior to analysis. Keep sample bottles closed until they are to be filled and be careful not to contaminate inside surfaces of containers. Fill containers without rinsing and cap immediately.

Sampling procedure

  • Remove the aeration screen or other attachments from the faucet. Some older faucets may require pliers to remove the screen.
  • If tap cleanliness is in doubt, it may be cleaned with either an alcohol prep pad or a mild solution of Clorox bleach.
  • Run the hot water first (if available) for 2-3 minutes, followed by cold water for 2-3 minutes.
  • Reduce the water flow to permit filling bottle without splashing.
  • Fill the sample container(s) and recap immediately.
  • Label the samples (see below)
  • Place samples in cooler with ice or ice pack and deliver to the laboratory as soon as possible.

Special sampling instructions for radon or volatile organics

If sampling for radon or volatile organics, special vials are required and available from us free of charge. They must be filled so that there are no air bubbles present after capping the vials. This is really easier than it sounds and is best achieved by topping off the vial under a slow, steady stream of water to fill it as much as possible. After filling and capping the vial, invert it and observe for any rising air bubbles. If there are bubbles, just add some more water.


Label bottles with your name, address, date and time sampled.

Common improper sampling techniques

Do not take bacteria samples from a hose as they will almost certainly fail. Use a faucet that has been cleaned properly.

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