I have a small trickle into a toilet bowl that I'm trying to stop as it's causing rust lines and wasting water. The flapper is relatively new and I ran my finger along the edge of the valve rim to see if there was anything abnormal and it seemed smooth to me. Any other suggestions on where to look for the source of the problem?
Update: I've replaced the fill valve and the trickle is still there. Going to replace the flapper and scrub the flush valve rim with fine steel wool before assuming the flush valve needs to be replaced.
Update: That seems to have fixed it.