TDS means total dissolved solids. Health Canada treats TDS as an aesthetic and operational parameter; a combined dissolved-solids number does not identify each substance in the sample. [8]
Three questions that keep a demonstration useful.
- What exactly does this instrument measure or estimate?
- Which question can this reading answer, and which questions need other tests?
- How does the result connect to the specific equipment being discussed?
TDS, hardness and bacteria are different questions.
On a small screen, swipe the table to see every column.
| Question | What to ask for |
|---|---|
| How much hardness is present? | A hardness measurement, with its units. |
| What does this TDS number represent? | An explanation of the measurement and its limits. |
| Is a named chemical present? | A laboratory test for that parameter. |
| What about bacteria? | Appropriate laboratory microbiological testing. |
Keep the whole report.
Record the sample location, date, whether treatment was bypassed and the method used. If you compare two readings, use consistent sampling conditions. Ask for the complete report before making a purchase decision.
A lower TDS number should not be presented as proof of improved hydration or freedom from all contaminants. A useful recommendation should connect the measurements to a specific, supported treatment goal.
Quick questions
Is 500 mg/L a universal safe/unsafe line?
Health Canada’s TDS value of 500 mg/L is an aesthetic objective, not a single-number safety certificate. [8]
What should I bring to ECW?
Your lab report, any meter readings and a description of what you want to improve.