Hi David, I don't think it's necessary to boil your water when using it for your starter, but if you do so be sure to allow it to cool to close to room temperature before using. We've found that almost all water that is suitable for drinking will work well in a sourdough starter, although if your water is heavily treated and smells of chlorine it won't hurt to leave it out for several hours or overnight in an open container, so some of the chemicals dissipate. 

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