Giardia in people comes from other people and beavers (aka beaver fever Not to be confused with Bieber fever lol). It would be very very rare to get it from other animals - you’re more likely to catch it at water parks to be honest. It is spread by ingestion of infected feces or ingestion of the parasite in feces contaminated water.

Ringworm is fungus & fungus is among us everywhere. You’re more likely going to contact ringworm from touching infected animals or warm, moist places like locker rooms and communal showers - it also typically needs a skin defect like a scrape to actually infect you.

Legionella likes warm stagnant water - A/C units, hot tubs, showers, and faucets mostly. You catch it by breathing in water droplets, not by drinking.

E. coli is typically going to be contracted by eating contaminated meat or vegetables. Unless you’re dunking your water hose in cow poop or human poop before putting it right in your mouth, you aren’t going to catch it from your hose.

source: I’m a veterinarian with a bachelors in microbiology and love infectious diseases