A system for power line communications between an in-home wireless network and a pool or spa. The system may include a spa network interface in electrical wired connection to an in-home network interface. The spa power line communication module may be hard wired to a spa control unit, and power to the spa may be provided by one or more of a first 120V conductor having a first phase of power, a second 120V conductor having a second phase of power, a ground conductor, and a neutral conductor. The system may optimize the connection between the in-home powerline communications module connected to one phase of power via a home receptacle, and the spa powerline communications module by testing the connection over each conductor and selecting the conductor with the best throughput.