Total dissolved solids in Drinking-water. Background document for development of WHO Guidelines for Drinking-water Quality.
Originally published in Guidelines for drinking-water quality, 2nd ed. Vol. 2. Health criteria and other supporting information. World Health Organization, Geneva, 1996.

The presence of dissolved solids in water may affect its taste. The palatability of drinking water has been rated by panels of tasters in relation to its TDS level as follows:

Excellent - less than 300 mg/litre (300ppm)
Good - between 300 and 600 mg/litre (300 to 600ppm)
Fair - between 600 and 900 mg/litre (600 to 901ppm)
Poor - between 900 and 1200 mg/litre (901 to 1201ppm)
and unacceptable greater than 1200 mg/litre (1201ppm)

Water with extremely low concentrations of TDS may also be unacceptable because of its flat,insipid taste.
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