Quality class

Chemical parameters

*Electrical conductivity (µS/Cm)

*Cl⁻ (mg/L)

* ${\text{NO}}_3^{-}$ (mg/L)

**DO (mg/L)

**DCO (mg/L)

**DBO₅ (mg/L)

I

Excellent

<400

<200

<5

>7

<30

<3

II

Good

400 - 1300

200 - 300

5 - 25

7 - 5

30 - 35

3 - 6

III

Average

1300 - 2700

300 - 750

25 - 50

5 - 3

35 - 40

6 - 10

IV

Poor

2700 - 3000

750 - 1000

50 - 100

3 - 1

40 - 80

10 - 25

V

Poor

>3000

>1000

>1000

<1

>80

>25