1. A watertight electrical compartment of an irrigation device, comprising:an electrical compartment body comprising a chamber with an open end, threads, and a sealing section, the sealing section located closer to the open end of the chamber than the threads;
at least one sealing ring having a diameter configured for mating with the sealing section;
a cap having an open end, a closed end, and an internal diameter configured to have a sliding fit with the sealing section and an interference fit with the at least one sealing ring when the compartment is assembled; and
a cap retainer having threads configured to threadedly mate with the threads of the compartment body, the cap retainer further having first and second ends, the cap retainer configured to receive at least a portion of the cap through the first end.