I am looking for a statistical amounts which are allowed. Some students say it is 0 for all bacteria, which I think is false. I found this USA source.
I found there
- Total Coliforms (including fecal coliform and E. Coli) mg/l. No more than 5.0% samples total coliform-positive (TC-positive) in a month.
- Giardia lamblia: 99.9% removal/inactivation.
What is the right place to look for such information?