We have recently shown how path integral simulations can be streamlined by decomposing the potential into a sum of rapidly varying short-range and slowly varying long-range contributions. In this talk, I will describe an efficient way to perform this decomposition for systems with electrostatic interactions, and illustrate the method with an application to a flexible water model. In the limit of large system size, where the calculation of long-range forces dominates, the present method enables path integral (and ring polymer molecular dynamics) simulations of liquid water to be performed with less than twice the computational effort of classical molecular dynamics simulations [1,2]. [1] T. E. Markland and D. E. Manolopoulos, J. Chem. Phys.129, 024105 (2008). [2] T. E. Markland and D. E. Manolopoulos, Chem. Phys. Lett. 464, 256 (2008).