Unscrew the button or screw that retains the tackle in place, remove the deal with, then unscrew or take out protect plate. This exposes the body and spindle. If there is water in the best of spindle and the outer human body is wet, it’s a sign the O-ring is leaking.  https://water-pressure-issues89011.spintheblog.com/35104146/new-step-by-step-map-for-plumbing-inspection