128IOC Sample Collection – Things to Remember
Sample instructions should be supplied with the sample containers from the laboratory. If the
laboratory fails to include sample instructions, contact the laboratory and request sample
instructions.
Some general practices to remember:
- Samples should be collected at the entry point to
the distribution system after all treatment (finished
water) - Select a sampling faucet that does NOT have an
aerator (sampling must be done with
minimum aeration - Run the water until the temperature is as cold as it
gets - Just before sample collection, adjust to a very low
flow. Do not change the flow while
collecting the sample - Routine nitrate and nitrite samples should be
collected on a Monday or a Tuesday - When filling sample bottle, tip bottle slightly so that
water flows down the side wall of the container.
Bring bottle to an upright position as it fills - Call the laboratory if bottles are received broken
(or break while collecting samples) - The owner or operator of a water supply must maintain chemical analysis reports (results) or a
summary of those reports for at least 10 years.
Chain of Custody Procedures
Because a sample is physical evidence, chain of custody procedures are used to maintain and
document sample possession from the time the sample is collected until it is introduced as
evidence. Chain of custody requirements will vary from agency to agency.
However, these procedures are similar and the chain of custody outlined in this manual is only a
guideline. Consult your project manager for specific requirements.
If you have Physical possession of a sample, have it in view, or have physically secured it to prevent
tampering then it is defined as being in “custody." A chain of custody record, therefore, begins
when the sample containers are obtained from the laboratory. From this point on, a chain of custody
record will accompany the sample containers.