the faucet. It is awkward to obtain water samples form fire hydrants and drinking
fountains. Ordinarily, nothing is gained by sampling a tap on the dead and of a
distribution system.
b. Procedure for Collecting and Forwarding Water Samples.
(1) Select a suitable cold-water faucet that has no leakage. Open the tap
and let the water flow long enough to pull in water from the water main, serving that
particular building. A flow for 3 to 5 minutes should be sufficient.
(2) Determine the chlorine residual and pH and record this information on
DO Form 686 (Fluoride/Bacteriological Examination of Water) while waiting for the
water to run before collecting the sample. The number of copies required of this form
varies from one installation to another. The original and at least one copy must be
submitted with the water sample. The original is returned to report the laboratory
findings. The laboratory will advise as to the exact number of copies needed. Other
copies may be routinely required by the surgeon, the post engineer, and other
interested activities.
(3) Close the water tap and flame the outside and inside lip of the tap with a
candle or alcohol lamp to destroy any live organisms that might be present.
(4) Reopen the tap and let the water flush out the soot and other
combustion products that resulted from flaming. Then adjust the tap to produce a
gentle, easy, smooth flow of water, thus preventing splashes and contaminated water
from getting into the sample bottle.
(5) Remove the hood and screw cap from the sample bottle and hold them
together to prevent the cap from becoming contaminated. Place the sample bottle
under the flowing tap and fill it to the neck.
(6)
Replace the cap and hood on the sample bottle while they are still
together.
(7) Close the water tap and record information pertaining to the sample on
DO Form 686 (see figure 3-1). Record the sample number on the sample bottle at this
time also.
(8)
Complete DO Form 686 carefully. Each block on the form serves an essential
purpose. For example, it is important to identify the collection point and the specific tap
from which the sample was obtained. The water from this tap must be checked further
if it is found to contain coliform group organisms. Any special requirements should be
entered in the space labeled "Remarks." Leave blank those blocks to be completed in
the laboratory.
MD0160
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