The presence of silanol defects ((SiOH) x ; i.e., the hydrophility of a material) stabilizes H 2 O within zeolite pores and impacts adsorption energies for H 2 O within BEA and MFI zeolites. The literature, however, lacks an understanding for how the structures that H 2 O forms depends on the combination of zeolite topology and (SiOH) x densities. Moreover, the thermochemical properties of these H 2 O structures will likely exhibit a complex dependence on the pore diameter and (SiOH) x density, because the importance of SiOH functions may change as H 2 O loses opportunities to hydrogen bond via spatial constraints. To understand the role of SiOH functions on stabilizing H 2 O structures within zeolite pores, we measured in situ infrared (IR) spectra and conducted molecular dynamics (MD) simulations of the H 2 O present within both hydrophilic and hydrophobic variants of the Ti-zeolite frameworks when these materials are immersed in liquid water. Titanium substituted zeolites with the FAU (1.3 nm supercages), BEA (0.65 nm pores), MFI (0.55 nm pores) frameworks and siliceous CDO (0.45 nm pores) were synthesized through post-synthetic modification or hydrothermal synthesis to prepare materials with a range of controlled topologies (e.g., 2D pore networks, 3D supercages), mean pore dimensions (0.45 -1.3 nm), and densities of (SiOH) x . Here, we make comparisons primarily among materials that contain the greatest and lowest densities of (SiOH) x (i.e., the most hydrophilic and hydrophobic samples). Materials named Ti-zeolite-OH are the variant of the framework that contains the greatest densities of (SiOH) x (i.e., are the most hydrophilic), while those denoted as Ti-zeolite-F were synthesized to contain low densities of (SiOH) x (i.e., are hydrophobic). The MD simulations of hydrophilic materials involved structures containing ~5 (SiOH) 4 defects per unit cell place at non-adjacent tetrahedral sites but otherwise located randomly. The same (SiOH) 4 density was used in simulations of Si-CDO-OH samples to facilitate equitable comparisons, although this material contains fewer (SiOH) x groups than other Ti-zeolite-OH samples (Fig. ). MD simulations of hydrophobic structures made use of pristine frameworks with zero (SiOH) x groups. Detailed characterization of all materials, the specifics of experimental methods, spectral and rate analysis methods, and computational methods are in the supporting information.