W. Va. Code § 8-19-11
Rates or charges for water or electric power fixed precedent to the issuance of bonds shall not be reduced until all of said bonds shall have been fully paid, and may, whenever necessary, be increased in amounts sufficient to provide for the payment of the principal of and interest upon such bonds, and to provide proper funds for the depreciation account and repair, maintenance and operation charges. If any surplus shall be accumulated in the repair, maintenance and operation fund which shall be in excess of the cost of repairing, maintaining and operating the waterworks or electric power system during the remainder of the fiscal year then current, and the cost of repairing, maintaining and operating the said waterworks or electric power system during the fiscal year then next ensuing, then any such excess may be transferred to either the depreciation account or to the bond and interest redemption account, and if any surplus shall be accumulated in the depreciation account over and above that which the municipality or county commission shall find may be necessary for the probable replacements which may be needed during the then present fiscal year, and the next ensuing fiscal year, such excess may be transferred to the bond and interest redemption account, and, if any surplus shall exist in the bond and interest redemption account, the same shall be applied insofar as possible in the purchase or retirement of outstanding revenue bonds payable from such account.
W. Va. Code § 8-19-11