If you have your own private well it will be okay for rehydrating yeast and for brewing. All municipal water supplies are treated with chlorine or chloramines, and in some cases both.
Municipal water can be treated with campden tablets to remove both chlorine and chloramines. Brewing with treated water can give a plastic or band aid flavor to the beer.
Chlorine will evaporate from water given about 24 hours in an open container. However you will not know if chloramines are also present.
Bottled drinking water, labeled spring water, would be best for rehydrating the yeast.
RO water, distilled water, spring water, and campden treated municipal water can be used for brewing with extracts. (All grain brewing sometimes needs certain mineral requirements for the brewing water.)