Reading a Water Report

A laboratory report becomes useful when the numbers, units, sample details and application are read together. This lesson teaches a repeatable way to organize a report before Puroxi reviews treatment options.

Learning objectives

Confirm that the sample represents the correct source and date.
Recognize results, units, detection limits and laboratory flags.
Group parameters into physical, chemical and biological information.
Connect results to symptoms without treating correlation as proof.
Identify missing information before choosing treatment.

Step 1 — Confirm the sample identity

Check the customer or site, sample point, source, collection date and time, sampler, preservation, laboratory receipt and analysis dates. A kitchen-tap sample does not necessarily represent a raw well, and a shoreline sample does not necessarily represent a deep reservoir or process return line.

Step 2 — Read the number and its unit

A number without its unit is incomplete. Results may be reported as mg/L, µg/L, ppm, ppb, CFU, MPN, NTU, µS/cm or another unit. Do not compare two values until their units and basis are the same. “Less than” results normally mean the substance was not detected above the stated reporting limit—not necessarily that none exists.

Laboratory scientists testing water samples and recording environmental analysis results

Step 3 — Separate results into groups

Physical: temperature, colour, turbidity, solids and odour observations.
General chemistry: pH, alkalinity, hardness, conductivity and total dissolved solids.
Metals and minerals: iron, manganese, calcium, magnesium and application-specific metals.
Nutrients and nitrogen: ammonia, nitrite, nitrate and phosphorus.
Biological: total coliforms, E. coli, algae identification and other requested organisms.
Process indicators: dissolved oxygen, ORP, COD, BOD or other application-specific measurements.

Step 4 — Compare with the correct objective

A drinking-water guideline, crop sensitivity limit, aquaculture target, equipment specification and wastewater discharge limit are not interchangeable. The report must be evaluated against the intended use, applicable jurisdiction and the customer’s defined treatment objective.

Step 5 — Look for relationships

Parameters can influence one another. Temperature affects oxygen solubility. pH and alkalinity influence chemical behaviour. Hardness and alkalinity may contribute to scale potential. Ammonia, nitrite, dissolved oxygen and temperature interact in aquaculture and biological treatment. These relationships help form questions; they do not justify a treatment recommendation without the rest of the system information.

Step 6 — Record what is missing

Mark absent parameters, unclear units, old samples, unusual sampling conditions and results that should be confirmed. Ask whether peak demand, seasonal water, untreated source water and treated water have all been represented.

Knowledge check

Why is “5” not a usable result without a unit?
What does a “less than” symbol usually tell you?
Why can a result be acceptable for one use and unsuitable for another?
What sample information should be confirmed before reviewing treatment?

ANSWERS

1) The scale and meaning are unknown.

2) The analyte was below the stated reporting/detection limit.

3) Applications and regulatory criteria differ.

4) Source, sample point, date/time, collection method and laboratory handling.

PUROXI PRINCIPLE

Understanding Always Comes Before Recommendation.