toilet "noise"

We have a rainbird automatic lawn sprinkler system. I've noticed that when it is automatically going from one "station" to another, one bathroom toilet sounds like it is filling for 2-3 seconds,the noise stops, then the next station starts. Can anyone tell me why and how to fix it?

The pressure in your main line can be low when sprinkers are running; shoot up at the moment the valve turns off; then drop again when the next valve opens. Fluctuations like this can affect the toilet fill valve. If you replace a ballcock type with a Fluidmaster 400A, then you would have less problems.

Thanks Jimbo!