What Should Be the TDS of Drinking Water? A Simple Chart

What should be the TDS of drinking water?

For drinking water, BIS IS 10500 sets an acceptable total dissolved solids (TDS) limit of 500 mg/L. It also specifies a permissible limit of 2,000 mg/L in the absence of an alternate source. That higher allowance is conditional—not a preferred target for everyday drinking water.

There is no single TDS number that proves water is safe. TDS describes the overall concentration of dissolved substances, including salts and minerals; it does not identify each substance or reliably detect harmful microbes. Water below 500 mg/L can still contain contaminants requiring treatment.

For a household in Kanpur, the practical answer is to assess TDS alongside source-water testing and the purifier’s model-specific guidance, rather than chase an arbitrary “ideal” reading.

A simple drinking-water TDS chart

This chart uses the BIS limits rather than unsupported labels such as “perfect,” “healthiest,” or “unsafe” based only on TDS. Readings are expressed in mg/L; many handheld meters display ppm, which is approximately equivalent for ordinary dilute water samples.

• Up to 500 mg/L: Within the BIS acceptable TDS limit. This does not confirm microbiological safety or compliance with limits for individual chemicals.
• Above 500 to 2,000 mg/L: Above the acceptable limit, but within the permissible TDS limit only in the absence of an alternate source. Assess the water’s composition and other quality parameters before deciding on treatment.
• Above 2,000 mg/L: Exceeds the BIS permissible TDS limit. Arrange laboratory assessment and seek advice on a suitable drinking-water source or treatment system.
• Very low readings: Not automatically healthier, and not enough to diagnose a problem. Review the source-water report and purifier manual rather than deliberately adding untreated water.

Safe checks you can make at home

A handheld TDS meter is useful for tracking changes, but most estimate TDS from electrical conductivity. Calibration, temperature and the meter’s conversion setting can affect the displayed result. Small differences between meters may not represent a meaningful change.

• Follow the meter manual for calibration, rinsing and measurement. Use a clean container without soap residue.
• Measure normally dispensed water, allow the reading to stabilise, and repeat an unexpected result.
• Record the date, sample point and reading. Comparing the same outlet under similar conditions is more useful than comparing unrelated samples.
• Check for changed taste, odour, colour, reduced flow, leaks or warning lights. Neither their presence nor absence establishes safety.
• If there is leakage near electrical components, avoid contact and seek professional help. Do not open powered or pressurised purifier housings.

When a laboratory or technician is needed

Use a competent water-testing laboratory when contamination is suspected, the supply source changes, or water develops unexplained changes. Ask the laboratory which microbiological and chemical tests fit the source and concern. A TDS-only test cannot answer whether bacteria, arsenic, fluoride or other specific contaminants meet relevant limits.

A technician is appropriate for persistent output changes, unusual operation, leaks, reduced production or repeated alarms. Diagnosis should consider feed-water quality, operating conditions, filter condition and the manufacturer’s specifications—not just one outlet reading.

Do not adjust a blending or TDS-control arrangement simply to reach a preferred number. Mixing untreated water into treated water can reintroduce contaminants. Any adjustment must follow the model’s design and preserve the treatment needed for the tested source.

Choose maintenance by condition, not a universal schedule

Follow the model manual for inspection, sanitation and replacement requirements. Usage, source-water quality, performance and service indicators affect maintenance needs; a universal replacement interval or TDS target is not suitable for every purifier.

For equipment-related help, Aqua Life Guard is an independent multi-brand provider at 302 Barra-II Main Rd Sector 4 Barra 2, Kanpur, open 24 hours. It is not an authorised brand service centre or a brand customer-care service. Equipment servicing does not replace laboratory confirmation of water quality.