In this topic, I will explain, how the effective or the capability of water pressure in the fire hydrants can be controlled in order that decreasing of ratio is not exceeded. This case study is carried out by doing the test and control cautiously. In fact, we could not control the decreasing of water pressure totally, though we still have methods, how to reduce it. We have two methods in doing the test. Only the fire engine officer who has a lot of experience can do it. The procedure how to do the first method will be explained in my presentation. For the second method, a special instrument will be used. The function is to measure the water pressure. The experience gained by the fire engine officer who si known how to used the instrument can do the etest. However, morre time is needed if the second method is chosen compared to the first one. They are several factors which are meeded to follow in order to control the water pressure whether the test is done or not. The factors are concerned with the position of fire hydrant, the position of fire engine car and fire hydrant, fire hydrants supervision and fire hydrant selection.