Water Coliform Sample Compliance

Audit water-sample coliform observations against a supplied per-sample allowance, retaining tested volumes; nondetection is not guaranteed sterility.

Description

Water-sample compliance is a comparison with an explicit allowance for each observed sample.

Water-sample compliance is a comparison with an explicit allowance for each observed sample. Tested volume remains important because nondetection in a small aliquot is not evidence that all water is sterile.^[1]

Audit water-sample coliform observations against a supplied per-sample allowance, retaining tested volumes; nondetection is not guaranteed sterility.

When to use Water Coliform Sample Compliance

Use this tool to audit water-sample coliform observations against a supplied per-sample allowance, retaining tested volumes; nondetection is not guaranteed sterility.

Prepare the sample, count, growth or assay measurements requested by this tool. Confirm units, sampling periods and reporting bases; supply independently established comparison criteria where requested.

How to use Water Coliform Sample Compliance and understand its results

Prepare the sample, count, growth or assay measurements requested by this tool. Confirm units, sampling periods and reporting bases; supply independently established comparison criteria where requested.
Enter sampleIds, coliformCounts, testedVolumesMl, maximumAllowedCount using the field table and calculation rules, then run the tool.
Read nonconformingSamples, totalTestedVolumeMl, allObservedSamplesConform. The explanation below defines the units, signs, ordering and any flags or placeholder values.
If the tool reports an input issue, correct the values and run it again. Apply the stated assumptions when interpreting a successfully returned result.

Input field	Meaning	Value type; see rules below	Requirement
sampleIds	Sample ids	list of string	Required
coliformCounts	Coliform counts	list of number	Required
testedVolumesMl	Tested volumes ml	list of number	Required
maximumAllowedCount	Maximum allowed count	integer; minimum: 0	Required

Enter distinct sample IDs with aligned nonnegative integer counts and positive tested volumes in mL, plus a nonnegative integer count allowance. The tool returns IDs exceeding the allowance, total tested volume and a flag true when none exceed it. Equality passes. Counts are compared per sample without volume normalization.

Paired lists must be nonempty and have equal lengths.

nonconforming if observedCount > maximumAllowedCount

Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.

Output field	Meaning	Value type
nonconformingSamples	Nonconforming samples	list of string
totalTestedVolumeMl	Total tested volume ml	number
allObservedSamplesConform	All observed samples conform	boolean

json

{
  "input": {
    "sampleIds": [
      "A",
      "B"
    ],
    "coliformCounts": [
      0,
      1
    ],
    "testedVolumesMl": [
      100,
      100
    ],
    "maximumAllowedCount": 0
  },
  "output": {
    "nonconformingSamples": [
      "B"
    ],
    "totalTestedVolumeMl": 200,
    "allObservedSamplesConform": false
  }
}

Limitations and assumptions

The caller supplies the applicable policy and sampling design. This does not identify organisms, assess representativeness, establish drinking-water safety or convert counts to a common-volume concentration.

Numeric inputs must be finite. Follow the calculation-specific rules for overflow, underflow and exceptional cases. Lists are limited to 100,000 entries; the rules above may require smaller limits. Missing required fields, extra fields, wrong value types and violations of the calculation rules are input errors. A successfully returned false flag is an evaluated outcome; its meaning is explained above.

Alternative or Complementary methods

Use Tube Design MPN Estimate: Fit a Poisson tube-positivity MPN by maximum likelihood using actual inoculum volumes, replacing a fixed three-tube lookup table. For a complementary task, use Food Three Class Sampling Plan: Evaluate an n/c/m/M-style three-class food plate-count plan using caller limits, not a universal food-safety determination.

References

Water Coliform Sample Compliance — tool.io

Similar or alternative tools

Tube Design MPN Estimate
Fit a Poisson tube-positivity MPN by maximum likelihood using actual inoculum volumes, replacing a fixed three-tube lookup table.
Food Three Class Sampling Plan
Evaluate an n/c/m/M-style three-class food plate-count plan using caller limits, not a universal food-safety determination.