HHO gas is an alternative energy that can replace fossil energy sources. HHO gas can be produced in several ways including water electrolysis. In this study the researchers used the electrolysis method of well water using NaHCO₃ catalyst in this study. The researchers used variations in the distance between the wheels, namely 2mm, 4mm, and 6mm. From the research, it was concluded that the time needed to produce HHO gas in the first 50 was the fastest at a distance of 2 mm, which is 95 seconds. While at the latest at a distance of 6 mm, 123 seconds. HHO gas flow rate at a distance of 2 mm is greater than the flow rate at a distance of 4 mm and a distance of 6 mm. The smaller the distance between plates, the faster the HHO gas will be generated. which is used during the electrolysis process, where the lower voltage is obtained with a distance of 6 mm which is 3.4 volts while the lowest current is obtained at a distance of 2 mm which is 4.25 amperes. The lowest electrical energy is obtained at a distance of 2 mm ie 50 ml starting using energy of 1266.35 joules From several factors that affect the efficiency of the HHO generator, the highest efficiency is found at a distance of 2 mm, which is an average of 37.90% and the lowest efficiency at a distance of 6 mm, which is 20.58%, so that the efficiency is obtained plate 2 mm.