Cephalosporium stripe disease of winter wheat (Triticum aestivum L.) is caused by the soil borne fungus Cephalosporium gramineum [Nisikado & Ikata (Hymenula eerealis Ell. & Ev)]. The effect of C. gramineum on root activity and subsequent soil water depletion is unknown. Our objective was to measure water use and soil water depletion patterns for six winter wheat genotypes with differing reactions to C. gramineum, under disease and nondisease conditions. Six winter wheat genotypes, ‘Marias’, ‘Win° ridge’, ‘Redwin’, ‘Lenore’, MT 7579, and MT 7811 were evaluated for grain yield in replicated control and inoculated plots in 1982 and 1983 near Bozeman, MT, of an Amsterdam silt loam (fine silty mixed family of Haploborolls). Soil water was measured in each plot at 15‐cm depth increments to 145‐cm with a neutron moisture meter. Soil water measurements were taken at roughly weekly intervals commencing in early May and continuing until harvest in early August. C. gramineum reduced grain yield, water use, and water use efficiency in both years but to a greater extent in 1982 than in 1983. Lenore proved least susceptible and Marias and MT 7811 were most susceptible as measured by reduction in grain yield, water use, and water use efficiency when averaged over both years. Genotypes differed in rate of water use in both years in the presence of the disease, but differences among genotypes were detected only in 1982 in the non‐disease situation. Infection by C. gramineum affected water depletion patterns least in Lenore and Winridge, and most in Marias and MT 7811. Genotype ✕ time and genotype ✕ depth interactions were such that relative differences among genotypes were amplified with increasing time and depth. C. gramineum affected soil water extraction throughout the soil profile. Reduction in water extraction may be due to reduced root activity and/or reduced demand for water by infected plants.