Ok... This is what I am getting. Testing is for Chlorine or/and Floride, both are present in City water. If you test positive you are getting cited for a violation, It is up to you to prove yourself in court. Thats what I get. Keep in mind this will be a civil violation, therefore, it will be harder for you to not be found liable. Civil is broader than criminal. EX. OJ was found not guilty in criminal, but in civil he had to pay.
The city will need the location you obtained the water and a contact w/number, they will verify the source, according to that water official.