Nothing in this chapter contained shall operate to effect an impairment of any inchoate right to divert and use water while the application of the water in question to a beneficial use is being prosecuted with reasonable diligence, having due regard to the circumstances surrounding the enterprise, including the magnitude of the project for putting the water to a beneficial use and the market for the resulting water right for irrigation or power or other beneficial use, in the locality in question.
RCW 90.03.460