The blue water footprint (WF) is an indicator of freshwater required to produce a given end product. Determining the blue WF for milk production, the seasonal water use and the impact of water conservation are important sustainability considerations for the dairy industry in Ontario (Canada). In this study, a water footprint network (WFN) method was used to calculate the seasonal blue WF’s from in-barn water use data and the fat–protein-corrected milk (FPCM) production. Various water conservation options were estimated using the AgriSuite software. Results showed that the total water use (L of water·cow⁻¹·d⁻¹) and the average blue WF (L of water·kg⁻¹ of FPCM) were 246.3 ± 6.8 L·cow⁻¹·d⁻¹ and 7.4 ± 0.2 L·kg⁻¹, respectively. The total water use and the blue WF could be reduced to 182.7 ± 5.1 L·cow⁻¹·d⁻¹ (25.8% reduction) and 5.8 ± 0.1 L·kg⁻¹ (21.6% reduction), respectively, through adaptive water conservation measures as the reuse of the plate cooler and milk house water. For example, conservation practices could reduce the milk house wash water use from 74.3 ± 8.8 L·cow⁻¹·d⁻¹ to 16.6 ± 0.1 L·cow⁻¹·d⁻¹ (77.7% overall reduction).