Receiver functions (RFs) are widely used to image the crust and shallow mantle in various tectonic settings. They are calculated by deconvolving the vertical component of teleseismic P waves from the horizontal (radial and transverse) components via spectral regularization (e.g., water-level or Wiener filtering). Due to the nature of this operation, only the radial and transverse RFs are recovered, which represent approximations to the P-to-S reflectivity structure of the subsurface. This project implements a novel method for RF calculation that uses spectral whitening of the vertical component during deconvolution to resolve the P-to-P and P-to-S reflectivity structure at a station. When applied to stations located in the forearc of the Cascadia subduction zone, we hypothesize that this will yield a better-constrained model of the plate interface structure and the presence of fluids. To test the validity of the whitened RF method, we first calculate water-level RFs for a single station and optimize the processing parameters to properly resolve the signals from the subducting plate structure using the radial and transverse components. We then compare them with the three-component whitened RFs and investigate the whitening parameters that best reproduce the water-level RF data. We expect to use the P-to-S and P-to-P information from the whitened RFs to produce a better model with less uncertainty. This will solidify the whitened receiver functions as a tool for understanding fluid content within the Cascadia region, with the aim of further applying this method elsewhere.