Parameters

Formula

Rank Value

Water classification

SAR

$\frac{\text{Na}}{\sqrt{\frac{\text{Ca}+\text{Mg}}{2}}}$

0 - 6

Good

6 - 9

Doubtful

>9

Unsuitable

Na%

$\frac{\left(\text{Na}+\text{K}\right)}{\left(\text{Ca}+\text{Mg}+\text{Na}+\text{K}\right)}\times 100$

<20

Excellent

20 - 40

Good

40 - 60

Permissible

60 - 80

Doubtful

>80

Unsuitable

RSC

$\left({\text{CO}}_3+{\text{HCO}}_3\right)-\left(\text{Ca}+\text{Mg}\right)$

<1.25

Good

1.25 - 2.4

Doubtful

>2.5

Unsuitable

MH

$\frac{\text{Mg}}{\text{Ca}+\text{Mg}}\times 100$

<50

Suitable

>50

Unsuitable