Hydro-geochemical Investigation and Quality Assessment of Groundwater for Drinking and Agricultural Use in Jawaharlal Nehru University (JNU), New Delhi, India - Management of Natural Resources in a Changing Environment - page 8

Number of samples
Pre-monsoon Water class Range Post-monsoon

Total dissolved solids (TDS) classification (Davis and DeWiest 1996) (mg/l)
Desirable for drinking <500 05 06

Permissible for drinking 500-1,000 04 03

Useful for irrigation 1,000-3,000 - -

Unfit for drinking and irrigation >3,000 - -

Total dissolved solids (TDS) classification (Freeze and Cherry 1979 ) (mg/l)
Fresh water type

<1,000 08 09

Brackish water type 1,000-10,000 01 -

Saline water type 10,000-100,000 - -

Brine water type >100,000 - -

Total hardness (TH) classification (Sawyer and McCarty 1967 ) (mg/l)
Soft <75 - -

Moderately hard 75-150 01 -

Hard 150-300 07 09

Very hard water >300 01 -

Electrical conductivity (EC) classification (Wilcox 1955 ) ( μ S/cm)
Excellent <250 - -

Good 250-750 03 02

Fair/Medium 750-2,250 05 07

Poor/Bad 2,250-5,000 01 -

Sodium percent (% Na) classification (Wilcox 1955 ) (%)
Excellent 0-20 - -

Good 20-40 02 04

Permissible 40-60 05 03

Doubtful 60-80 02 02

Unsuitable >80 - -

Sodium adsorption ratio (SAR) classification (Richards 1954 ) (meq/l)
Excellent 0-10 09 09

Good 10-18 - -

Fair 18-26 - -

Poor >26 - -

Residual sodium carbonate (RSC) classification (Richards 1954 ) (meq/l)
Good <1.25 05 09

Medium 1.25-2.5 04 -

Bad >2.5 - -

Chloride (Cl − ) classification (Stuyfzand 1989 ) (meq/l)
<0.14

Extremely fresh 02 01

0.14-0.85 Very fresh 01 03

0.85-4.23 Fresh 04 03

4.23-8.46 Fresh brackish 01 01

8.46-28.21 Brackish brackish 01 01

28.21-564.13 Salt - -

>564.13 Hypersaline - -