Sampling Scenarios Municipal Water
SAMPLE CATEGORY
DESCRIPTION
Routine
RAW & DISTRIBUTION samples
collected on a routine basis with
designated or alternate site #’s or
addresses. These designated areas are
issued directly from the IEPA
Replacement
Samples collected to replace a sample that
was: received past the 30 hr hold time,
previously or currently frozen, received in
a broken bottle, received w/out the dates
& times collected, received but suffered a
laboratory accident
Samples taken because of low water main
pressure (below 20 PSI) or the EPA issued
your facility a boil order
Boil Order
New Construction
Need New Construction
Permit #
Samples collected for new water main
construction, water tower construction &
new well construction. New hydrants &
hydrant replacements are NOT considered
new construction
Other/Checks
Samples collected for situations not listed
on the COC such as well/tower repairs,
customer requests, any hydrant work,
service line work, well pump work, etc.
Repeat & Finished Samples
ROUTINE & Finished samples that
confirm POSITIVE for coliform
Can only have one sample per month.
If you take 40 samples or more then you
can have up to 5 % of your samples bad
Ex. 5% of 40 = 2/month
(Upon receipt of a resample, because the
previous routine sample was positive for
coliform, the REPEAT box MUST be
checked on the COC followed w/ the
previous POSITIVE lab sample #)
PLEASE CHECK W/ LABORATORY
PERSONNEL WHEN DROPPING
OFF A REPEAT SAMPLE TO
INSURE THE PAPERWORK IS
FILLED OUT PROPERLY W/ THE
CORRECT SAMPLE NUMBER
FROM THE PREVIOUS POSITIVE
DAY !!
Invalid Sample Replacements
ROUTINE samples collected that have
>200 colonies but confirms NEGATIVE
for coliform
(Upon receipt of a replacement, because
the previous routine sample was invalid,
the INVALID box MUST be checked on
the COC followed w/ the previous
INVALID lab sample #)
SAMPLING / RESAMPLING
PROCEDURES
For samples that confirm POSITIVE for
coliform SEE the REPEAT category. For
samples that have GREATER than 200
colonies but confirm NEGATIVE for
coliform SEE the INVALID
REPLACEMENT category
Only ONE replacement sample is
required if needed. The sample must be
taken from the same site or address that
the first sample was taken from
For a chlorinated system take ONE set of
samples & for an unchlorinated system
take TWO sets. If the boil order is a
system wide order then the set should
consist of 5 DISTRIBUTION samples. If
it is a partial system order then 1
distribution sample for every 1200 ft. of
water main affected should be collected.
Samples CAN have < 200 colonies but
must confirm NEGATIVE for coliform
Samples are collected as follows: 1 set of
samples is taken after main chlorination.
Zero colonies = done. Each site that has
colonies must be resampled twice a
minimum of 24 hrs apart. Each sample
MUST have 0 colonies to PASS. Each
site must be resampled until 2
consecutive samples pass from each site
sampled. Need NC #
If samples confirm positive for coliform
or are invalid because of >200 colonies a
follow-up sample should be collected.
This follow-up sample will also be
marked OTHER on the COC.
If a ROUTINE RAW sample is
POSITIVE for coliform only 1 sample
must be collected from the same site until
it passes. If a ROUTINE
DISTRIBUTION sample is POSITIVE
for coliform, 3 REPEAT samples should
be collected for each sample that is
POSITIVE. 1 of the 3 is collected from
the same site. The 2nd is collected
upstream & the 3rd is collected
downstream each w/in 5 service
connections. If a Finished is positive
collect the same site and 2 downstream. If
you collect ONLY 1 distribution sample
per month then you will need to collect 4
REPEAT samples. For supplies
collecting < 5 dist./month, then the
following month they need a total of 5
distributions and the normal raw samples
they collect.
One replacement sample must be
collected. Samples must be collected until
a good sample result is achieved.
However, if the invalid replacement
sample has < 200 colonies & confirms
POSITIVE for Coliform NOW it must be
treated as a POSITIVE ROUTINE
sample – SEE REPEAT sampling
procedure