only 40% of ppl who get giardia will ever get symptoms
the rest can carry it and pass it on without ever getting sick.
if you know you are a carrier why bother treating?
the only ppl who get sick from crypto are those with very weak immune systems eg infants, HIV+, the elderly, transplant patients with immune suppression, etc if you dont fall into these categories don't worry.
The waterborne health risk you should be most worried about is fecal coliforms. Not giardia or crypto. Don't drink downstream from the toilets.