A proposed wind farm could eventually bring $5 million in property tax revenue to Washington County per year. Assessor Lil Perry told supervisors this week that would be the case if they adopted a special valuation ordinance that increases the tax rate annually by 5%. Perry recommends supervisors look into the special ordinance, as it would help keep the revenue local. They appointed a special committee this week to do just that. This year the Iowa legislature approved allowing wind farms to enjoy both the special valuation and a state tax credit.