Unscrew the button or screw that holds the handle set up, take out the tackle, then unscrew or eliminate address plate. This exposes the body and spindle. When there is water in the highest of spindle and also the outer overall body is damp, it’s a sign the O-ring is leaking.  https://felixnftjx.blog4youth.com/35387100/how-much-you-need-to-expect-you-ll-pay-for-a-good-toilet-repairs