My male cat has never drunk tap water, only our milk (his choice!) I know it is supposed to be bad for them but he is nearly 20 now so never did him any harm. When he used to go out a lot he drank rainwater but has always been healthy and has hardly ever had to go to the vets. However now he drinks loads of tap water and I just wondered, do you think it is just because he is old or maybe indoors all the time?