What is the acceptable TDS level for drinking water?

The acceptable limit is 500 mg/L. In the absence of an alternate source, a permissible limit of 2000 mg/L is allowed (Table 2).

Is E. coli allowed in drinking water?

No. E. coli must be absent in any 100 ml sample (Table 5).

What is the acceptable pH range for drinking water?

The acceptable range is 6.5 to 8.5, with no relaxation allowed (Table 1).

What is the maximum permissible limit for Fluoride?

The permissible limit is 1.5 mg/L, while the acceptable limit is 1.0 mg/L (Table 2).

IS 10500

: 2012

Drinking water specification (second revision)

CurrentEssentialSpecificationEnvironmental · Water Supply and Plumbing

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This standard specifies the essential quality requirements for drinking water in India. It defines two levels of limits for various physical, chemical, bacteriological, and radiological parameters: an 'Acceptable Limit' and a 'Permissible Limit' for use only when no alternative water source is available.

Specifies the acceptable limits for various physical, chemical, and microbiological parameters of drinking water quality.

Quick Reference Values

pH Value6.5 to 8.5 (No relaxation)

Total Dissolved Solids (TDS) Acceptable Limit500 mg/l

Total Dissolved Solids (TDS) Permissible Limit2000 mg/l

Total Hardness (as CaCO3) Acceptable Limit200 mg/l

Total Hardness (as CaCO3) Permissible Limit600 mg/l

Iron (as Fe) Acceptable Limit0.3 mg/l

Fluoride (as F) Permissible Limit1.5 mg/l

Residual Free Chlorine (Minimum)0.2 mg/l

Practical Notes

A key distinction is between the 'Acceptable Limit' (desired level) and the 'Permissible Limit' (maximum allowable level in the absence of an alternate source). Using water with parameters in the permissible range may have adverse health effects over time.

This standard applies to piped public water supply and water from other sources, but not to packaged drinking water, which is covered by IS 14543.

Testing for residual chlorine (min 0.2 mg/L) at the consumer end is crucial to ensure disinfection has been effective throughout the distribution network.