82
Class III Water is generally not safe for irrigation except under certain type of soil
conditions and for salt tolerant crops.
Drinking Water Standard
Physical Characteristics :
Characteristics
Upper limit
Turbidity
100 ppm (silica scale)
Colour
20 (Std cobalt scale)
Taste
Not objectionable
Odour
Not objectionable
These limits are mandatory for filtered water supplies, for others, their application
is subject to reasonable judgement and discretion based on local conditions.
Table 6.8 : Chemical Characteristics of DrinkingWater - (Source : Todd, 1995)
Constituent
Upper limit, ppm
Lead (Pb)
0-1
Fluoride (F)
1 - 5
Arsenic (As)
0.05
Selenium (Se)
0.05
Hexavalent Chrimium
0.05
Copper (Cu)
3.00
Iron (Fe) Manganese (Mn) together
0.30
Magnesium (Mg)
125
Zinc (Zn)
15
Chloride (Cl)
250
Sulfate (SO4)
250
Phenol
0.001
Total solids, desirable
500.0
Total solids, permitted
1000.0
The limits for the first five constituents are mandatory; the others are
recommended. The standards as specified by WHO and BIS (Indian Standard)
are indicated under Chapter VII (Table 7.1). Suggested Water Quality
Tolerance for the Industries are given in Table 6.9.
