I came home from vacation and my water bill was $400 dollars. All three toilets were stuck with the flapper valve in the up position and leaking by. I bought and installed new tank internals with the float type valve that goes straight up and down vice the ball on the long arm type with the flapper valve and chain. The chain is a nuisance and gets hung up causing the valve to stay open. Also, the flapper valve gets gunked up at the hinge. Its clean water but for some reason it gets fouled up. Its not costly and is relatively easy to replace the internals. you can buy everything at Lowes or Home depot. If you have a new home its a slam dunk. The buliders use the cheapest materials they can find on the market unless you upgrade.