This document presents a convex optimization approach for automated disaggregation of water consumption data into end uses. It proposes modeling each end use as having finite operating modes and piecewise constant consumption profiles. A sparse optimization problem is formulated to minimize the fitting error between modeled and measured consumption, regularized by an L1-norm penalty to promote sparsity. Tests on electricity and water consumption data show the approach can accurately disaggregate consumption into end uses like toilet flushes and showers. Future work includes refinements to handle lower resolution data and tailored numerical solvers.