Disclosed herein is a representative liquid heater that maintains a liquid temperature at a consistent and desirable temperature. The liquid heater includes a housing, a liquid pump, a temperature controller, and a mounting structure. The housing houses a power supply and a heating element that receives power from the power supply. The liquid pump receives power from the power supply and pumps liquid from a liquid container to the heating element, which heats the water. The temperature controller turns on or off the heating element to increase and/or decrease the temperature of the liquid from the liquid container. The mounting structure includes an inlet structure and an outlet structure, both of which are connected to the housing. The inlet structure receives liquid from the liquid container and the outlet structure ejects the liquid from the housing. The inlet structure and the outlet structure are configured to be in a “U” shape such that the inlet structure and the outlet structure can be mounted on the edge of the liquid container. A base of the U-shaped inlet structure and outlet structure rests on the top edge of the liquid container and the two arms of the U-shaped inlet structure and outlet structure are adjacent to a wet side and a dry side of the liquid container. The base of the U-shaped inlet structure and the outlet structure are configured to be telescopic that expands to accommodate various thicknesses of at least one liquid container.