BACKGROUND: Little information is yet available for the association between daily water intake, a modifiable lifestyle factor, and Alzheimer's disease (AD) pathology and cerebrovascular injury in the living human brain. OBJECTIVE: Our aim was to explore the correlation between daily fluid intake and in vivo AD pathologies (i.e., amyloid-β (Aβ) and tau) and cerebrovascular injury. METHODS: 287 cognitively normal (CN) older adults completed extensive clinical assessments, daily fluid intake evaluations, and multimodal brain imaging at both the initial baseline and the subsequent 2-year follow-up. RESULTS: Low daily fluid intake was significantly associated with a higher level or a more rapid increase of Aβ deposition, especially in apolipoprotein E4 negative individuals. Meanwhile, low daily fluid intake was cross-sectionally related with cerebrovascular injury. CONCLUSIONS: Our findings suggest that high daily fluid intake is associated with decreased brain amyloid deposition, indicating that sufficient daily fluid intake may be helpful for prevention of AD.