The amount of the deficit in the income of a self-liquidating municipal public utility applicable to interest and debt redemption, or the prospective amount of such deficit as determined by the local government board or, in the case of a project undertaken pursuant to the urban redevelopment law, the Division of Planning and Development in the Department of Conservation and Economic Development, shall be capitalized at 5% and the capital sum so determined shall not be deductible from the gross debt.
N.J.S. § 40A:2-48