My toilet will start running every half hour or so. It does not occur after flushing and when the running occurs, jiggling the handle does not help. I've looked in the tank and nothing appears wrong (of course that doesn't mean anything!). It is a Kohler and is about 5 years old. Any direction would help. Thank you!!

It's likely the flapper vave leaks slowly, dropping the water level until the float opens its' water valve... jiggling the handle can't help... Flapper valves, handle chains and so-on are readily available and cheap... The water in the tank is tap-water, no matter the sediment on the walls of the tank... use a paper towel to wipe the flapper valve seat when doing the job, and inspect for nicks, tears or sediment accumulation... Good luck...

Rasin2004 is right on. Use that paper towel to handle the old flapper. That deteriorated rubber will put black on every in site.

Both great answers. Run your finger around the flappers flat part. If it's wavy then replace it. When you replace the flapper it will have to be adjusted. With the flapper seated the linkage wants to have 1/4" of play. Too much play and the flapper doesn't get pulled back enough giving you a short flush. Too tight and it lets water seep past the flapper. I adjust the chain by the link and if it needs fine tuning, I bend the flush lever rod a bit untill I have the desired play in the linkage. One more thing about a flapper. you will see where the old flapper hooks onto the base of the white overflow tube. On a older type with no hooks the flapper has a ring that slips down over the overflow tube to the seat. If your tank has hooks, take a sharp knife or scissors and cut the neoprene ring off on the marks provided and hook the flapper on the hooks. Leaving the ring on will interfere with the flush. The water level in your tank should be 3/8 to 1/2" below the top of the overflow tube when the tank's filled. And the little tube wants to run from the ballcock and connect to the white overflow tube.. good luck, Tom

Put a few drops of food coloring in the tank after it fills up. You will see the color flow into the bowl from the bottom indicating a flapper problem. I usually use blue or red for a light color toilet...

Every one is helping you and I will share the following link with you at may help you, Thanks.

John

Replace The Toilet Fill Valve, Flush Valve Or Flapper (http://www.rd.com/familyhandyman/content/17646/)