The sun is a source of heat energy that can be utilized as a source of renewable energy. One form of solar thermal utilization is with Solar Water Heater (SWH). Conventional SWH uses water as a heat storage medium. The use of water has disadvantages including low energy density so it requires large volumes that cause heavy construction. To overcome this, paraffin wax is used as a phase change material (PCM), where paraffin wax has a high energy density. Much research has been done about SWH, but there is not much to discuss about the rate of heat absorption and the rate of temperature rise in water and PCM that occur in SWH tanks. The purpose of this study was to determine the rate of heat absorption and temperature rise in the SWH tank during the charging process with a variation of discharge. This study uses water as a Heat Transfer Fluid (HTF) and PCM in the form of paraffin wax as a heat storage medium. This study uses a heater to simulate solar heat. The testing process starts with a heater connected to the voltage regulator which will heat the water driven by the pump to enter the tank. Thermocouples installed in the tank will be recorded temperature every 5 seconds once in the data logger. Then the charging process will be done with 4 variations of discharge, namely 600, 700, 800, and 900 mLPM. The results showed an increase in temperature during the charging process at each discharge variation. The absorption rate value obtained by paraffin wax during latent conditions receives more energy than the sensible absorption rate. The highest latent heat absorption value is obtained at a variation of 900 mLPM with a value of 110.52 Joules / s, while in the largest sensible conditions a value of 24.49 Joules / s is obtained. The highest value of water absorption rate is obtained at a variation of 900 mLPM with a value of 664.86 Joules / s.