§54-21 Reserve fund. The board of water supply may provide for the accumulation of a fund for the purpose of financing major replacements, or extensions and additions, the average estimated annual increment to which, for a period of ten years, shall not exceed fifteen per cent of the gross revenue of the board in any fiscal year. [L 1961, c 155, pt of §1; Supp, §145A-11; HRS §54-21]