I live in a co-op. This summer I had my bathroom redone with a new toilet and piping. Recently I have noticed that out of the blue my toilet makes a running noise for a couple of seconds through out the day.. The water isn't moving in the bowl but you can hear the noise.. What is causing that and do I need to have a plummer come in and check it out.
Ellen

You have a worn flapper that is leaking the water out of the tank. The reason the water comes on throughout the day indicates it is a leak and the leveling system is just replenishing the water. Buy a new flapper.

Open the lid and check the water level. It should be 1/2" below the white overflow tube when the tank's filled. The flapper chain wants to have 1/4" of play when the flapper's seated. And last, run your fingers around the flapper flat side. If you feel wavy edges replace the flapper. One of these should stop your drip. Good luck, Tom