S. 4862 directs the Department of Agriculture to allow farmers to receive prevented planting payments for irrigation-dependent cropland that remains unplanted due to insufficient water availability. Under current rules, farmers typically must actually attempt to plant their crops to qualify for these payments, but this bill would extend eligibility to acreage that farmers reasonably decide not to plant because they expect inadequate irrigation water for the season. To qualify, the land must have irrigation infrastructure in place, been irrigated within the previous four years, been planted with the same crop previously, and be unsuitable for dryland farming. The bill phases out payment eligibility over time, reducing payments by 50 percent for years five through eight of consecutive water shortages, 75 percent for years nine and ten, and eliminating payments entirely after year ten, with permanent ineligibility after that point. The bill also requires the Agriculture Department to revise its drought regulations to account for water shortages at irrigation sources and to consult with local farm committees when determining whether conditions qualify as natural disasters.