Simple water purification system

The invention relates to a simple water purification system comprising a pure water production valve, a front filter core and an RO membrane reverse osmosis filter core sequentially connected on a tap water inlet pipe in series. A pure water outlet pipe is connected to a pure water outlet of the RO membrane reverse osmosis filter core. A pure water outlet valve is arranged on the pure water outlet pipe. A concentrated water outlet pipe is connected to a concentrated water outlet of the RO membrane reverse osmosis filter core. A throttle valve is arranged on the concentrated water outlet pipe. According to the invention, the pure water production valve, the front filter core and the RO membrane reverse osmosis filter core are directly connected on the tap water inlet pipe in series, such that pure water production is realized. With a flushing valve connected in parallel with the pure water production valve, the PO membrane filter core can be flushed under tap water pressure. When the pure water production valve and a pure water outlet valve are an integral pure water four-way valve, and the flushing valve and a concentrated water outlet valve are an integral flushing four-way valve, the entire system does not need electricity input, such that energy is saved.