All surface water sites in San Juan County are to meet the Extraordinary or Class AA Washington State water quality standard.
The designation of good water quality in the above chart combines Class A and Class B from WA surface water standards.

Class AA (extraordinary)
pH -  6.5-8.5
Turbidity- shall not exceed 5 NTU (over background level)
Temperature - shall not exceed 16°C
Dissolved Oxygen- shall exceed  9.5 mg/L
Fecal coliform – shall not exceed a geometric mean of 50 colonies/ 100mL and  not have more than 10 percent of all samples collected exceed 100 col./100mL

Class A (excellent)
pH -  6.5-8.5
Turbidity- shall not exceed 5 NTU (over background level)
Temperature - shall not exceed 18°C
Dissolved Oxygen- shall exceed  8.0 mg/L
Fecal coliform – shall not exceed a geometric mean of 100 colonies/ 100mL and  not have more than 10 percent of all samples collected exceed 200 col./100mL

Class B (good)
pH -  6.5-8.5
Turbidity- shall not exceed 10 NTU (over background level)
Temperature - shall not exceed 21°C
Dissolved Oxygen- shall exceed  6.5 mg/L
Fecal coliform – shall not exceed a geometric mean of 200 colonies/ 100mL and  not have more than 10 percent of all samples collected exceed 400 col./100mL

Class C (fair)
pH -  6.5-9.0
Turbidity- shall not exceed 10 NTU (over background level)
Temperature - shall not exceed 22°C
Dissolved Oxygen- shall exceed  4.0 mg/L
Fecal coliform – shall not exceed a geometric mean of 200 colonies/ 100mL and  not have more than 10 percent of all samples collected exceed 400 col./100mL

Nutrients – Are not very clearcut it really depends on the background levels for the particular area.  So the numbers below are guidelines.

Nitrates should not exceed 1mg/l 

Phosphates should not exceed .1mg/l