A liquid dosing system is disclosed and can include an inlet conduit and an outlet conduit. The inlet and outlet conduits can each be configured to fluidly communicate a heat exchanger of a water heater. The liquid dosing system can include one or more connector conduits configured to fluidly connect the inlet conduit and the outlet conduit to define a fluid circuit by at least the inlet conduit, the heat exchanger, the outlet conduit, and the one or more connector conduits. The liquid dosing system can include a pump configured to pump water through the fluid circuit, a reservoir configured to store an additive, and a dosing device configured to dispense the additive into the fluid circuit.