The domestic injection water preparation system uses distillation, which is of course related to the quality of domestic reverse osmosis. It should be pointed out that different distilled water machines have different requirements on source water. Different types of distilled water machines can be prepared with purified water, deionized water and deep soft water as source water, respectively, due to differences in performance. On the other hand, the preparation of purified water from water that meets drinking water standards or the use of purified water in accordance with the standard injection water preparation system does not necessarily guarantee that the effluent meets the specified standards. The performance of the device is related. It should also be pointed out that the water quality of the source water must be monitored and the water intake point should be avoided as much as possible.