Section 465.370  Sample Collection, Handling and Preservation

When the laboratory has been delegated responsibility for sample collection, handling, and preservation, there shall be strict adherence to correct sampling procedures, complete identification of the sample, and prompt transfer of the sample to the laboratory as specified in "Standard Methods for the Examination of Water and Wastewater."  In addition, the following standards for sample collection, handling, and preservation of potable water samples shall be met:

a)         In order for the sample to be representative of the potable water system, the sampling program shall include examination of the finished water at selected sites that systematically cover the distribution network.

b)         Minimum sampling frequency shall be as specified in 35 Ill. Adm. Code 611, Subpart L (Microbiological Monitoring and Analytical Requirements).

c)         Water shall be sampled from cold water taps that are free of aerators, strainers, hose attachments, and water purification devices.  Prior to sampling, a steady flow of water shall be maintained from the tap for 2 to 3 minutes to clear the service line.

d)         The sample bottle shall be filled allowing at least ¼ inch of air space from the top to provide space for mixing.  A minimum sample volume of 100 ml shall be collected.

e)         The sample report form shall be completed in indelible ink immediately after collecting the sample and shall contain the following information: name of system (public water system site identification number, if available); sample identification (if any); date and time of collection; sample site location; sample collector's name and organization (if not the water system); persons transporting the samples from the system to the laboratory (if not the sampler); transportation condition (e.g., <10º C, protection from sunlight); sample type (e.g., routine, repeat); and total chlorine residual (if applicable).

f)          Sample bottles shall be of at least 120 ml capacity, of sterile plastic or hard glass, wide mouthed with glass stopper or screw cap (metal or plastic), and capable of withstanding repeated sterilization.  Presterilized plastic bags, with or without a dechlorinating agent, may be used.  Metal caps with exposed bare metal on the inside shall not be used.  When samples are to be collected from chlorinated water supplies, sodium thiosulfate shall be added to the sample bottles in an amount sufficient to provide an approximate concentration of 100 mg per liter of sample prior to sterilization of the sample bottles.  As an example, 0.1 ml of a 10% sodium thiosulfate solution is required for a 120 ml sample bottle.

g)         When the sample is delivered to the laboratory:

1)         The following information shall be added to the sample report form:

A)        Date and time of sample arrival;

B)        Name of carrier; and

C)        Name of the person receiving the sample for the laboratory; and

2)         Each sample shall be assigned a laboratory number.  In the event of a repeat or replacement sample, the number assigned to the original sample shall also be recorded.

h)         Records necessary to establish chain-of-custody of the samples shall be maintained.

i)          Samples shall be analyzed on the day of arrival in the laboratory, preferably within 30 hours after collection.  If a sample is run after the 30 hour limit, the laboratory must indicate on the report form that the results may be invalid due to excessive delay before processing.  Without exception, samples arriving more than 48 hours after collection shall be refused and a new sample requested.

j)          Samples of potable water for heterotrophic plate count analysis shall be refrigerated and delivered to the laboratory within 6 hours after collection, and analyzed within 2 hours after receipt in the laboratory.

k)         Source water samples shall be held at <10º C and time of initiation of analyses shall not exceed 8 hours from time of collection.