In a healthy individual, urine is sterile and safe to drink in small quantities or come into contact with. If a person is on medication it may be passed into their urine. So, if this is something you enjoy, it would be important to think about that particular risk. There are also risks if there is a bacterial infection of the urethra or if they have any diseases. There have also been cases of skin rashes due to urine allergies.
Unlike some other paraphilias, this is considered a rather safe form because there is nothing illegal about this act.