This study examined the economic impact of a wintering barn facility on a dairy farm in the Tararua District, relative to its ability to reduce nitrogen leaching, as a means of achieving Horizon’s proposed nitrogen discharge limit. The analysis showed that the provision of a wintering facility had a significant impact in reducing nitrogen leaching, down to just above the required limit. The economic cost of this was significant, in the absence of improved payouts or the farmer intensifying the system to cover the cost of the facility. If the farm was intensified in order to cover the cost of the wintering facility, the level of nitrogen leaching rose accordingly. The study therefore indicates that the provision of a wintering barn as a means of reducing nitrogen leaching is problematic – while it can reduce leaching rates its economic viability is very dependent on payout levels and supplementary feed costs, and intensifying the system to improve the economic viability results in increased leaching rates well above the proposed limits.