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Coliform Sample Siting Plan

Coliform Sample Siting Plan. Ken Morin, P.E. BLM National Applied Resource Sciences Center. Coliform Sampling 40 CFR 141.21(a)(1).

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Coliform Sample Siting Plan

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

  2. Coliform Sampling40 CFR 141.21(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. • These plans are subject to State review and revision.

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

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

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

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

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

  8. 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)] • Public Notification Requirements [141.21(g) and 141.32] • Two positives in one month exceeds MCL [141.63(a)(2)] • Failure to monitor for coliforms [141.21(g)(2)]

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

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

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

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

  13. Sampling Following a Positive - 1 Tap • 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

  14. Sampling Following a Positive - 1 Tap [concluded] • Five “Increased” Routine Samples [141.21(b)(5)] • Routine samples must be taken in month following the positive [40 CFR 141.21(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

  15. Sampling Following a Positive - 2 Taps • 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)]

  16. Sampling Following a Positive - 2 Taps[concluded] • 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

  17. Sampling Following a Positive - 3 Taps • 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)]

  18. Sampling Following a Positive - 3 Taps[concluded] • 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

  19. Sampling Following a Positive - 4 Taps • 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)]

  20. Sampling Following a Positive - 4 Taps [concluded] • 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

  21. Sampling Following a Positive - 5 to 7 Taps • 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)]

  22. Sampling Following a Positive - 5 to 7 Taps[concl’d] • 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

  23. Sampling Following a Positive 8 or More Taps • Four Repeat Samples to be Taken per 141.21(b)(2) • 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

  24. Repeat Sample Collection • 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)] • Repeat Sample Locations [141.21(b)(2)] • All Repeats to be Taken on Same Day [141.21(b)(3)]

  25. Repeat Sample Collection • If 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 141.63 [141.21(b)(4)] • State May Still Require Additional Sampling

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

  27. “Increased” Routine Sample Collection • 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)] • Except 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)]

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