|
Sl.
No.
|
Substance
or Characteristics
|
Requirement
Desirable Limit
|
Undesirable
Effect Outside the Desirable Limit
|
Desirable/
Essential
|
Remarks
|
| 1. |
Colour,
Hazen Units, Max. |
--
|
Above
10 |
Essential |
May
be extended to 50 only if toxic substances
are not suspected in absence of alternative
sources. |
| 2. |
Odour |
Objectionable |
--
|
Essential |
a)Test
cold and when heated.
b)Test at severaldilutions. |
| 3. |
Taste |
Agreeable |
--
|
Essential |
Test
to be conducted only after safety has been
established. |
| 4. |
Turbidity,
NTU, Max. |
10 |
Above
10, Consumer acceptance decreases. |
Essential |
May
be extended upto 25, in absence of alternative
sources. |
| 5. |
pH
Value |
6.5
to 8.5 |
Beyond
this range the water will affect the mucous
membrane and/or water supply system. |
Essential |
May
be relaxed upto 9.2 in absence of alternative
sources. |
| 6. |
Total
Hardness (as CaCO3) mg/l Max. |
300 |
Encrustation
in water supply structure and adverse effects
on domestic use. |
Essential |
May
be extended upto 600 in the absence of other
sources. |
| 7. |
Calcium
(as Ca), mg/l, Max. |
75 |
Encrustation
in water supply structure and adverse effects
on domestic use. |
Desirable |
May
be extended upto 200, in the absence of other
sources. |
| 8. |
Magnesium
(as Mg), mg/l, Max. |
30 |
Encrustation
in water supply structure and adverse effects
on domestic use. |
Desirable |
May
be extended upto 100, in the absence of other
sources. |
| 9. |
Copper
(as Cu), mg/l, Max. |
0.05 |
Astringent
taste, dis-colouration and corrosion of pipes
fittings and utensils will be caused beyond
this. |
Desirable |
May
be relaxed upto 1.5. |
| 10. |
Iron
(as Fe), mg/l, Max. |
0.3 |
Beyond
this limit taste/appearance are affected &
has adverse effect on domestic uses and water
structures, and promotes iron bacteria |
Essential |
May
be extended upto 1.0 in absence of alternative
sources. |
| 11. |
Manganese
(as Mn), mg/l, Max. |
0.1 |
Beyond
this limit, taste/appearance are affected
on domestic uses and water supply structure. |
Desirable |
May
be extended up to 0.5 where alternate source
is not available. |
| 12. |
Sulphate
(as SO4), mg/l, Max. |
250 |
Beyond
this causes gastrointestinal irrigation when
magnesium of sodium are present . |
Essential |
May
be extended up to 400 provided magnesium (as
Mg) does not exceed 30. |
| 13. |
Chloride
(as Cl), mg/l, Max. |
250 |
Beyond
this limit, taste, corrosion and palatability
are affected |
Essential |
May
be extended up to 1000 in the absence of other
alternate sources. |
| 14. |
Nitrate
(as NO3)mg/l, Max. |
45 |
Beyond
this mathemoglobinaemia takes place. |
Desirable |
No
relaxation |
| 15. |
Fluoride
(as F), mg/l |
0.6
to 1.2 |
Low
floride level are linked with dental carries
above 1.5 it may cause fluorosis. |
Desirable |
If
the limit is below 0.6 water source should
be rejected but suitable public health measures
should be taken.Maximum limit may be extended
to 1.5 if no better alternate source is available. |
| 16. |
Phenolic
Compounds (as C6H5OH), mg/l, Max. |
0.001 |
Beyond
this it may cause objectionable taste and
odour. |
Desirable |
May
be relaxed up to 0.002. |
