Hydrophobicity is a documented problem in many sand soils worldwide. Potatoes are commonly grown in sandy soil in Idaho, but the occurrence and effect of hydrophobicity has not been documented in this region. The objectives of this research were to document hydrophobicity occurrence in Idaho and to determine its impact on tuber yield, size, grade, and occurrence of internal and external defects. Fifteen field locations were tested during 2004-06 under a variety of sand types and irrigation systems. Six replications, in a RCBD, with treatments including with and without a surfactant known to remedy hydrophobicity with other crops and in other regions. Total and US No. 1 yields increased on average by 5 and 8%, respectively, with application of a non-ionic surfactant. Soil moisture in hills where potatoes were growing had significantly better uniformity temporally and spatially.