Preliminary Charged-Current Single Charged Pion Cross Section Measurement on Water with the T2K Near Detector

Using 72\% and 77\% pure observed CC1$\pi^{\pm}$ ND280 Monte Carlo samples obtained after analysis cuts and corresponding to P0D water-in and water-out running modes respectively, a CC1$\pi^{\pm}$ cross section on water measurement was performed. A water-in/water-out event rate subtraction technique was utilized in the process to obtain a CC1$\pi^{\pm}$ event rate exclusively on water. Preliminary results are presented in a form of a flux-averaged cross section with statistical and systematic errors.