QUALITY REQUIREMENTS OF DRINKING WATER

Parameters Requirements (desirable limits) Undesirable effects when taken outside the permissible limits Permissible limit in absence of alternative source

essential feature

pH 6.5 – 8.5 Water beyond this limit will affect the mucous membrane and/or the water supply system no rest
color (hazen units), max 6.5 – 8.5 Above 5, consumer acceptance decreases 25
‘odor indisputable
Taste Agree
Turbidity, NTU, Max 5 Above 5, consumer acceptance decreases 10
Total Hardness (as CaCO.)3), Max 300 mg/L Encroachment in water supply infrastructure and adverse effect on domestic use 600 mg/L
Iron (as Fe), Max 0.30 mg/L Beyond this limit taste/appearance is affected, domestic uses and water supply structures are adversely affected, and iron promotes bacteria 1.0 mg/L
Cl, Max. as chloride 250 mg/L Taste, spoilage and palatability are affected beyond this limit. 1000 mg/L
residual free chlorine, min 0.20 mg/L

desirable traits

dissolved solids, max 500 mg/l In addition, taste is reduced and may cause gastrointestinal irritation. 2000 mg/l
Calcium (as Ca), Max 75 mg/l Encroachment in water supply infrastructure and adverse effect on domestic use 200 mg/l
Magnesium (as Mg), Max 30 mg/l 100 mg/l
Copper (As Cu), Max 0.05 mg/l astringent taste,

discoloration and

corrosion of pipes,

fittings and utensils

would cause

beyond

1.5 mg/l
manganese

mn), max

0.1 mg/l beyond this limit

taste/appearance

are affected,

adverse effect on

home use and

water supply

structures

0.3 mg/l
sulfate (as

therefore4), Max

200 mg/l beyond

gastrointestinal tract

jealous when

Magnesium O

400 mg/l
NO. as nitrates3 45 mg/l Also methane-moglobinemia occurs 100 mg/l
Fluoride, Max 1.0 mg/l Fluoride can be kept as low as possible. High fluoride can cause fluorosis 1.5 mg/l
alkalinity, max 200 mg/l beyond this limit the taste becomes unpleasant 600 mg/l

Reference

IS: 10500 – 1992 – Drinking water [SPECIFICATION]

Er. Mukesh Kumar

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Er. Mukesh Kumar is Editor in Chief and Co-Funder at ProCivilEngineer.com Civil Engineering Website. Mukesh Kumar is a Bachelor in Civil Engineering From MIT. He has work experience in Highway Construction, Bridge Construction, Railway Steel Girder work, Under box culvert construction, Retaining wall construction. He was a lecturer in a Engineering college for more than 6 years.