Standards for biological parameters for drinking water

Hi everyone,

In our drinking water lab, we investigate 7 biological parameters: chlorophyceae, cyanophyceae, crustaceae, protozoa, nematod, rotifer and diatoms.

is there a special standard for the count of these parameters in drinking water or if there should be none of them in drinking water, is there any special standard that mentions this?

After glancing at the references some friends suggested (like GUDI) now I am in doubt if it is necessary to test and count these parameters? Because cryptosporidium and giardia are mostly mentioned for monitoring.

I would appreciate if you can help me revise our instruction for groundwater, surface water and treatment plant influent and effluent. Please share the special reference for what you propose.