1

Colour (Qualitative)

Colourless

Aesthetic value

2

Total Dissolved Solids

< 500 mg/l

High TDS contributes mineral taste to water. Also causes damage to waters.

3

Turbidity 

5 NTU

An indicator of level of water clarity

4

pH

6.5 – 8.5 

If not within range, affects mucous membrane. If low, it tends to dissolve metals in its contact, and if high it is also undesirable because of excessive alkalinity.

5

Total Alkalinity (as CaC03)

< 200 mg/l

Indicates scale-forming or corrosive  tendencies of water

6

Chlorides (as CI)

< 250 mg/ l 

Taste becomes objectionable. Adversely affects plumbing if in excess

7

Sulphates (as S04)

< 200 mg/l

 High Sulphates have laxative effect and tend to form hard scales on heated vessels.

8

Nitrates (as NO3)

< 45 mg/l

High Nitrates causes blue-baby Syndrome that reduces the oxygen absorbing capacity of Blood.

9

Total Hardness (as CaCO3)

< 300 mg/l

More the hardness more difficult it is to lather the soap. Leaves precipitate in appliances reducing their efficiency.

10

Iron (as Fe)

< 0.3 mg/l

Imparts difficult to remove red strains. Promotes growth of iron bacteria which are a jelly like mass that plug the pipes.

11

Residual Chlorine

Min 0.2 mg/l

Chlorination is required to destroy the bacteria and oxidize the organic matter present in the water. The reason to maintain residual (excess) chlorine is to provide the safety margin against subsequent microbial contamination during storage and distribution.

12

Coliform MPN

0/100 ml

Presumptive test indicating contamination by animal excreta Presence indicates disease causing bacteria, needing immediate remedial action.

13

E. Coli

absent

Confirmatory test indicating contamination by animal excreta. Presence indicates disease causing bacteria, needing immediate remedial action.