CPHED,
Ministry of Urban Development, Govt of India
Standards for Drinking Water
- Physical and chemical standards:
| Sl.
No |
Characteristics
|
*Acceptable |
**Cause
for
rejection |
| 1. |
Turbidity
|
2.5 |
10 |
| 2. |
Colour
(units on platinum cobalt scale) |
5.0 |
25 |
| 3. |
Taste
and Odour |
Unobjectionable |
Unobjectionable |
| 4. |
pH |
7.0
to 8.5 |
6.5
to9.2 |
| 5. |
Total
Dissolved solids (mg/L) |
500 |
1500 |
| 6. |
Total
hardness as CaCO3 |
200 |
600 |
| 7. |
Chloride
as Cl (mg/L) |
200 |
1000 |
| 8. |
Sulphates
as SO4 (mg/L) |
200 |
400 |
| 9. |
Fluoride
as F (mg/L) |
1.0 |
1.5 |
| 10. |
Nitrates
as NO3 (mg/l) |
45 |
45 |
| 11. |
Calcium
as Ca (mg/L) |
75 |
200 |
| 12. |
Magnesium
as Mg (mg/L) |
30
# |
150 |
| 13. |
Iron
as Fe (mg/L) |
0.1 |
1.0 |
| 14. |
Magnesium
as Mn (mg/L) |
0.05 |
0.5 |
| 15. |
Copper
as Cu (mg/L) |
0.05 |
0.5 |
| 16. |
Zinc
as Zn (mg/L) |
5.0 |
15.0 |
| 17. |
Phenolic
compounds as Phenol (mg/L) |
0.001 |
0.002 |
| 18. |
Anionic
detergents as MBAS (mg/L) |
0.2 |
1.0 |
| 19. |
Mineral
Oil (mg/L0 |
0.01 |
0.3 |
| Toxic
Materials |
| 20. |
Arsenic
as As (mg/L) |
0.05 |
0.05 |
| 21. |
Cadmium
as Cd (mg/L) |
0.01 |
0.01 |
| 22. |
Chromium
as Hexavalent Cr (mg/L) |
0.05 |
0.05 |
| 23. |
Cyanides
as CN (mg/L) |
0.05 |
0.05 |
| 24 |
Lead
as Pb (mg/L) |
0.10 |
0.10 |
| 25. |
Selenium
as Se (mg/L) |
0.01 |
0.01 |
| 26. |
Mercury
as Hg (mg/L) |
0.001 |
0.001 |
| 27 |
Polynuclear
aromatic hydrocarbons (PAH) (ug/L) |
0.2 |
0.2 |
| Radio
Activity + |
| 28. |
Gross
Alpha activity (pCi/L) |
3.0 |
3.0 |
| 29. |
Gross
Beta activity (pCi/L) |
30.0 |
30.0 |
PCi = Pico Curie
Notes:
* The figures indicated
under the column “Acceptable” are the limits upto
which is generally acceptable to the consumers.
** Figures in excess of those mentioned
under “Acceptable” render the water not acceptable,
but still may be tolerated in the absence of alternative
and better source but upto the limits indicated
under column “Cause for Rejection” above which the
supply will have be rejected.
# If there are 250 mg/L
of sulphates, magnesium content can be increased
to a maximum of 125 mg/L with the reduction of sulphates
at the rate of 1 unit per every 2.5 units of sulphates.
+ It is possible that
some mine and spring waters may exceed these radio
activity limits and in such cases it is necessary
to analyse the individual radionuclides in order
to assess the acceptability or otherwise for public
consumption.
2.
Guideline values for bacteriological quality
| Organism |
Guideline
Value
(Number
/100 mL) |
Remarks |
| A Pipe water supplies |
| i) Treated water entering
the distribution system |
| Faecal
Coliform |
0 |
Turbidity
< 1 NTU |
| Coliform
Organisms |
0 |
For
disinfection with chlorine, pH preferably
8.0 free residual chlorine 0.2 -
0.5 mg/l following 30 minutes (minimum
contact) |
| ii) Untreated water
entering the distribution system |
| Faecal
Coliform |
0 |
|
| Coliform
Organisms |
0 |
In
98 % of samples examined throughout the
year in the case of large supplies when
sufficient samples are examined |
| Coliform
Organisms |
3 |
In
an occasional sample, but not in consecutive
samples |
| iii) Water in the distribution
system |
| Coliform
Organisms |
0 |
In
95% of samples examined throughout the year
in the case of large supplies when sufficient
are examined. |
| Coliform
Organisms |
3 |
In
an occasional samples, but not in consecutive
samples |
| B Unpiped
water supplies |
| Faecal
Coliforms |
0 |
|
| Coliform
Organisms |
10 |
Should
not occur repeatedly, if occurrence is frequent
and if sanitary protection can not be improved
an alternative source must be found, if
possible |
| C Emergency
water supplies |
| Faecal
Coliforms |
0 |
Advise
public to boil water in case of failure
to meet guideline values |
| Coliform
Organisms |
0 |
|
|
|
|
Source:
Guideline for Drinking Water Quality Vol. 1, a WHO
Publication
3. Virological quality of drinking water
It
is recommended that to be acceptable, drinking water
should be free from any viruses infectious for man.
This objective may be achieved (i) by the use of
water supply from a source which is free from wastewater
and is protected from faecal contamination; or (ii)
by adequate treatment of water source that is subject
to faecal pollution.
Adequacy
of treatment cannot be assessed in an absolute sense
because neither the available monitoring techniques
nor the epidemiological evaluation is sufficiently
sensitive to ensure the absence of viruses. However,
it is considered at present that contaminated source
water may be regarded as adequately treated when
the following condition are met.
-
A turbidity of 1 NTU or less in achieved.
-
Disinfection of the water with at least 0.5 mg/L
of free residual chloride after a contact period
of at least 30 minutes at pH below 8.0.
The
turbidity condition must be fulfilled prior to disinfection
if adequate is to be achieved. Disinfection other
than by chlorination may be applied provided the
efficacy is at least equal to that of chlorination
as described above. Ozone has been show to be effective
viral disinfectant, preferably for clean water,
if residuals of 0.3 – 0.4 mg/L are maintained for
4 minutes. Ozone has advantage over chlorine for
treating water containing ammonia, but unfortunately,
it is not possible to maintain an ozone residual
in the distribution system.
When
virological facilities can be provided, it is desirable
examine the raw water source and the finished drinking
water for the presence of viruses. This will provide
baseline data to evaluate the health risk faced
by the large volumes of drinking water (e.g. 100
– 1000 liters) |
