The conventional way of computing the electrostatic potential at a solute charge in water, Phi(infinity)-(Q), includes contributions from an infinite number of water molecules. Phi(infinity)(Q) varies by as large as 20 kcal/mol depending on the summation scheme or dielectric boundary. Here we show that Phi(infinity)(Q) is nonconvergent. By computing Phi(Q) as a sum of contributions from an interior, explicit water region, an intermediate, continuum water region, and an exterior, explicit water region using the same summation scheme, the two implicit water/ explicit water surface effects cancel and Phi(Q) converges to a single value, independent of the summation scheme.