Coliform Sample Siting Plan Ken Morin, P.E. BLM National Applied Resource Sciences Center

Coliform Sampling 40 CFR (a)(1) Routine monitoring. Public water systems must collect total coliform samples at sites which are representative of the water throughout the distribution system according to a written sample siting plan.Routine monitoring. Public water systems must collect total coliform samples at sites which are representative of the water throughout the distribution system according to a written sample siting plan. These plans are subject to State review and revision.These plans are subject to State review and revision.

Coliform Sample Siting Plan Plan elements are not defined in the regulations.Plan elements are not defined in the regulations. Very brief guidance is available from some States.Very brief guidance is available from some States. New BLM Drinking Water Manual will provided detailed requirements.New BLM Drinking Water Manual will provided detailed requirements.

Recommended Elements in Sample Siting Plan Map showing the following:Map showing the following: –Distribution system –Storage –Treatment –Taps –Identification name/number for each tap

Recommended Elements in Sample Siting Plan [continued] Break Distribution System into Zones if it is Looped or has Different Pressure Zones.Break Distribution System into Zones if it is Looped or has Different Pressure Zones. Alternate Samples Between ZonesAlternate Samples Between Zones Focus Samples At:Focus Samples At: –Dead ends –Heaviest use taps

Recommended Elements in Sample Siting Plan [continued] Routine Sample ScheduleRoutine Sample Schedule – Sample to be taken early in month/quarter – Quarter defined as Jan. - March, etc. Sampling ProceduresSampling Procedures How to Fill Out Lab FormHow to Fill Out Lab Form

Recommended Elements in Sample Siting Plan [continued] Description of Sampling that Must be Done if a Routine Sample Tests Positive [141.21(b)(2)]Description of Sampling that Must be Done if a Routine Sample Tests Positive [141.21(b)(2)] Do Not Disinfect Following a Positive Routine SampleDo Not Disinfect Following a Positive Routine Sample Actions to be Taken if a Repeat Sample Tests Positive [ (b)(4)]Actions to be Taken if a Repeat Sample Tests Positive [ (b)(4)]

Recommended Elements in Sample Siting Plan [continued] “Increased” Routine Samples Must be Taken Regardless of Whether Any Repeat Sample Tests Positive [141.21(b)(5)]“Increased” Routine Samples Must be Taken Regardless of Whether Any Repeat Sample Tests Positive [141.21(b)(5)] Public Notification Requirements [141.21(g) and ]Public Notification Requirements [141.21(g) and ] –Two positives in one month exceeds MCL [141.63(a)(2)] –Failure to monitor for coliforms [141.21(g)(2)]

Recommended Elements in Sample Siting Plan [continued] Disinfection Procedures for:Disinfection Procedures for: –Well –Storage tank –Distribution system

Recommended Elements in Sample Siting Plan [continued] Water System Startup ProceduresWater System Startup Procedures –Opening and closing which valves –Disinfection procedures for storage and distribution –Satisfactory coliform result prior to opening Operational Testing FrequencyOperational Testing Frequency

Recommended Elements in Sample Siting Plan [continued] Water System Shutdown ProceduresWater System Shutdown Procedures –Opening and closing which valves –Draining distribution and storage –Equipment to be brought back from the field

Recommended Elements in Sample Siting Plan [concluded] Recordkeeping RequirementsRecordkeeping Requirements State Reporting Requirements for:State Reporting Requirements for: –Positive repeat coliform result –Public notification postings –Operational testing results State Certification RequirementsState Certification Requirements

Sampling Following a Positive - 1 Tap One Repeat Sample [141.21(b)(3)]One Repeat Sample [141.21(b)(3)] –Four 100 mL samples: –first taken early in morning –second taken 2 or 3 hours later –third taken 2 or 3 hours after second –fourth taken 2 or 3 hours after third –Refrigerate or ice samples awaiting shipment to lab

Sampling Following a Positive - 1 Tap [concluded] Five “Increased” Routine Samples [141.21(b)(5)]Five “Increased” Routine Samples [141.21(b)(5)] –Routine samples must be taken in month following the positive [ 40 CFR (b)(5)] –Routine samples must be taken at regular time intervals throughout the month [141.21(a)(4)] –Therefore a sample must be taken every 5 or 6 days

Sampling Following a Positive - 2 Taps Four Repeat Samples [141.21(b)(2)]Four Repeat Samples [141.21(b)(2)] –One sample from each tap taken early in morning –One sample from each tap taken as late as possible the same day –Repeat samples must be taken on the same day [141.21(b)(3)]

Sampling Following a Positive - 2 Taps [concluded] Five “Increased” Routine Samples [141.21(b)(5)]Five “Increased” Routine Samples [141.21(b)(5)] –Routine samples must be taken at regular time intervals throughout the month [141.21(a)(4)] –one sample from each tap at the beginning of the month –one sample from each tap at the middle –one sample from original positive tap at the end of the month

Sampling Following a Positive - 3 Taps Four Repeat Samples [141.21(b)(2)]Four Repeat Samples [141.21(b)(2)] –One sample from each tap taken early in morning –One sample from the original positive tap taken as late as possible the same day –Repeat samples must be taken on the same day [141.21(b)(3)]

Sampling Following a Positive - 3 Taps [concluded] Five “Increased” Routine Samples [141.21(b)(5)]Five “Increased” Routine Samples [141.21(b)(5)] –Routine samples must be taken at regular time intervals throughout the month [141.21(a)(4)] –One sample from each tap at the beginning of the month –One sample from original positive tap and any other tap at the middle of the month

Sampling Following a Positive - 4 Taps Four Repeat Samples [141.21(b)(2)]Four Repeat Samples [141.21(b)(2)] –One sample from each tap –Repeat samples must be taken on the same day [141.21(b)(3)] –Samples are to be taken within 24 hours of notification of positive [141.21(b)(1)]

Sampling Following a Positive - 4 Taps [concluded] Five “Increased” Routine Samples [141.21(b)(5)]Five “Increased” Routine Samples [141.21(b)(5)] –Routine samples must be taken at regular time intervals throughout the month [141.21(a)(4)] –One sample from each tap at the beginning of the month –One sample from original positive tap at the middle of the month

Sampling Following a Positive - 5 to 7 Taps Four Repeat Samples [141.21(b)(2)]Four Repeat Samples [141.21(b)(2)] –One sample from original positive tap –Other samples from any three different taps –Repeat samples must be taken on the same day [141.21(b)(3)] –Samples are to be taken within 24 hours of notification of positive [141.21(b)(1)]

Sampling Following a Positive - 5 to 7 Taps [concl’d] Five “Increased” Routine Samples [141.21(b)(5)]Five “Increased” Routine Samples [141.21(b)(5)] –Systems that serve < 4,900 persons may collect all required samples on a single day if they are taken from different taps [141.21(a)(4)] –One sample from original positive tap at the beginning of the month –Four other samples any four different taps

Sampling Following a Positive 8 or More Taps Four Repeat Samples to be Taken per (b)(2)Four Repeat Samples to be Taken per (b)(2) Five “Increased” Routine Samples Taken From 5 Different Taps on the Same Day [141.21(b)(5) & (a)(4)]Five “Increased” Routine Samples Taken From 5 Different Taps on the Same Day [141.21(b)(5) & (a)(4)] –One of the samples should be taken at the original positive tap

Repeat Sample Collection Four Repeat Samples Must be Taken [141.21(b)(1)]Four Repeat Samples Must be Taken [141.21(b)(1)] Samples to be Taken Within 24 Hours of Positive Result Notification [141.21(b)(1)]Samples to be Taken Within 24 Hours of Positive Result Notification [141.21(b)(1)] Repeat Sample Locations [141.21(b)(2)]Repeat Sample Locations [141.21(b)(2)] All Repeats to be Taken on Same Day [141.21(b)(3)]All Repeats to be Taken on Same Day [141.21(b)(3)]

Repeat Sample Collection If Any Repeat Tests Positive Another Set of Repeats Must be Taken; [141.21(b)(4)] orIf Any Repeat Tests Positive Another Set of Repeats Must be Taken; [141.21(b)(4)] or Notify the State that the Coliform MCL has been Violated per [141.21(b)(4)]Notify the State that the Coliform MCL has been Violated per [141.21(b)(4)] State May Still Require Additional SamplingState May Still Require Additional Sampling

Repeat Sample Collection System with One Tap May Collect One Repeat Sample Each Day for Four Days; orSystem with One Tap May Collect One Repeat Sample Each Day for Four Days; or Collect a Single 400 mL Sample [141.21(b)(3)]Collect a Single 400 mL Sample [141.21(b)(3)] –This should be a composite sample

“Increased” Routine Sample Collection Five “Increased” Routine Samples Must be Taken in the Month Following a Positive Sample [141.21(b)(5)]Five “Increased” Routine Samples Must be Taken in the Month Following a Positive Sample [141.21(b)(5)] Collect Samples at Regular Time Intervals Throughout the Month [141.21(a)(4)]Collect Samples at Regular Time Intervals Throughout the Month [141.21(a)(4)] Except Systems that Serve < 4,900 PersonsExcept Systems that Serve < 4,900 Persons –May collect all required samples on a single day if they are taken from different taps [141.21(a)(4)]