Toilet running constantly from a stiff flapper
Why it happens here
Pathfinder's water leaves mineral deposits on the flapper and valve seat, so the rubber stiffens and stops sealing within a year or two. The toilet runs quietly until you notice the water bill.
Our approach
We replace the flapper with a silicone model that resists mineral buildup and smooth the valve seat before installing it. If the seat is badly scaled, we replace the whole flush valve so the new flapper has a clean surface.