(1) Categorical pretreatment standards may be adjusted to reflect the presence of pollutants in an industrial user's intake water in accordance with 40 CFR 403.15 (July 1, 1991) .   The department hereby incorporates herein 40 CFR 403.15, which is a federal regulation relating to net/gross calculation.   A copy of 40 CFR 403.15 may be obtained from the Department of Environmental Quality, PO Box 200901, Helena, MT 59620-0901.