Drinking water or potable water is water pure enough to be consumed or used with low risk of immediate or long term harm.
http://en.wikipedia.org/wiki/Drinking_water#Drinking_water_r...

Potable water is water which is fit for consumption by humans and other animals. It is also called drinking water, in a reference to its intended use. Water may be naturally potable, as is the case with pristine springs, or it may need to be treated in order to be safe. In either instance, the safety of water is assessed with tests which look for potentially harmful contaminants.
http://www.wisegeek.com/what-is-potable-water.htm

For potable (drinkable) water we offer a basic package of four tests to determine if the water meets drinking water standards. These tests are for coliform bacteria, e-coli bacteria, nitrates and nitrites. Recommended minimum testing for wells. Frequently we are asked to test for lead (especially important if there are children in the home), sodium (since water softeners add salt to the water and people are concerned about salt intake), and arsenic (which is found in high levels in certain areas and has been proven to cause cancer). We offer a comprehensive package that tests for coliform bacteria, e-coli bacteria, nitrates, nitrites, lead, sodium, arsenic and turbidity.
http://www.houseinspection.com/water.htm

Mislim da je ovaj link najkorisniji:
Interpretation of Water Potability Results
http://www.asinspectiongroup.com/water interpretation.pdf