Archive for the ‘Sampling’ Category

Sampling procedures

Friday, December 1st, 2023

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.


Sampling containers vary based on the packages we offer. For package choices, please see “Pricing” on the right side of the screen.  All containers can be procured at the laboratory, free of charge. If you have any questions regarding these supplies, please call us at 978-391-4428.

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 aeration screen or other attachments from faucet.
  • If tap cleanliness is in doubt it may be cleaned with either an alcohol prep pad or a weak solution of Clorox bleach.
  • Run hot water first (if available) for 2-3 minutes then turn off. Run the cold water for 2-3 minutes.
  • Reduce water flow to permit filling bottle without splashing.
  • Fill sample container(s) with cold water and recap immediately.
  • Deliver samples to the laboratory as soon as possible.
  • Samples must be received at the laboratory within 24 hours of collection.
  • Place samples in cooler with ice or ice pack if you are dropping off outside of business hours.

Special sampling instructions for radon or volatile organics

If sampling for radon or volatile organic compounds, special vials are required. They must be filled so that there is a solid column of water (no air bubbles or head space) present after capping the vials. Invert the vial after filling and observe for any rising bubbles/air. If there are any bubbles/air, add more water. (Note: Radon in Air has separate instructions included in the kit – please follow those instructions.)


If you are sampling from more than one location, please designate which bottles were taken from which location.

PLEASE NOTE: When sampling for a package, please fill all bottles at the same location.

For example: Our comprehensive package contains 5 bottles; fill all 5 bottles from one faucet, for example, your kitchen faucet.

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.