Categorization | Index Value | Water Quality |
Excellent | 95 - 100 | • Virtual absence of threat or impairment. • Conditions very close to natural or pristine levels. |
Good | 80 - 94 | • Minor degree of threat or impairment. • Conditions rarely depart from natural or desirable levels. |
Fair | 65 - 79 | • Occasionally threated or impaired. • Conditions sometimes depart from natural or desirable levels. |
Marginal | 45 - 64 | • Frequently threatened or impaired. • Conditions often depart from natural or desirable levels. |
Poor | 0 - 44 | • Almost always threatened or impaired. • Conditions usually depart from natural or desirable levels. |