Parameters

Rate of hazard

Water quality classes

Pre-monsoon

Monsoon

Post-monsoon

High Tide

Low Tide

High Tide

Low Tide

High Tide

Low Tide

pH^a,b

6.5 - 8.4

No problem

All

All

All

All

All

All

5.1 - 6.4 and 8.5 - 9.5

Moderate

0-5.0 and 9.5+

Severe

EC^c

(mS∙cm⁻¹)

<250

Excellent

All

All

All

All

250 - 750

Good

S1HT

S1LT,S2LT

750 - 2250

Permissible

S2HT - S5HT

S3LT - S5LT

>2250

Unsuitable

TDS^a,b

(mg/L)

<450

Good

S1LT

All

All

All

All

450 - 2000

Permissible

All

S2LT-S5LT

>2000

Unsuitable

Na^+a,b

(meq/L)

<3

No problem

All

All

All

All

3 - 9

Moderate

S1HT - S3HT

S1LT - S3LT

>9

Severe

S4HT, S5HT

S4LT, S5LT

$S{O}_4^{2-}$ ^d

(meq/L)

<4

Excellent

All

All

All

All

All

All

4 - 12

Good to injurious

>12

Injurious to unsuitable

$C{l}^{-}$ ^a,b

(meq/L)

<4

No problem

All

All

All

All

4 - 10

Moderate

S1HT - S3HT

S1LT - S3LT

>10

severe

S4HT, S5HT

S4LT, S5LT

$N{O}_3^{-}$ ^a,b

(mg/L)

<5

No problem

All

All

All

All

All

All

5 - 30

moderate

>30

severe

Na%^e

<20

Excellent

20 - 40

Good

All

All

S2HT - S5HT

S2LT - S5LT

40 - 60

Permissible

S1HT

S1LT

60 - 80

Doubtful

S1HT - S4HT

S1LT - S4LT

>80

Unsuitable

S5HT

S5LT

SAR^c

<10

Excellent

S1HT - S4HT

S1LT - S4LT

All

All

All

All

10 - 18

Good

S5HT

S5LT

18 - 26

Doubtful

>26

Unsuitable

RSC^f

<1.25

Safe

S2HT - S5HT

S4LT - S5LT

All

All

All

All

1.25 - 2.50

Permissible

S1HT

S1LT - S3LT

>2.50

Unsuitable