The Fill valve may need replacement. Look in the tank as it fills, does the stream come out as a stream or more of a spray, there is a chance that a residue build up is restricting and a soak in something like CLR might fix things. If you decide to go with a replacement fill valve it may be a good time to replace the flushvalve and flapper as well. Fluidmaster makes a nice kit that is relatively inexpensive and is good quality parts at almost any hardware store.
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The Fill valve may need replacement. Look in the tank as it fills, does the stream come out as a stream or more of a spray, there is a chance that a residue build up is restricting and a soak in something like CLR might fix things. If you decide to go with a replacement fill valve it may be a good time to replace the flushvalve and flapper as well. Fluidmaster makes a nice kit that is relatively inexpensive and is good quality parts at almost any hardware store.