Well, there is bacteria in all tap water, but it is usually a very small amount... If you haven't noticed any unusual signs or symptoms in regard to having an infection, I wouldn't worry about it if I were you. If you aren't convinced that nothing is wrong, or you still feel worried, you can always go see a gynecologist, have an examination, and explain your concerns...
Almost all techniques except humping on a bed are safe if done with great care. Humping on bed can harm as it will put the pressure on the penis in case of male and with female it may harm delicate part like clitoris.
OH okay thank you guy so much!