A liquid purification system comprising a source liquid supply, a purified liquid feed line to a consumer, and a liquid purification unit in fluid communication with both the source liquid supply and the purified liquid feed line to a consumer; the liquid purification unit includes - a liquid-liquid type container consisting of a body and a means that defines a storage cavity for purified liquid and a displacement cavity for source liquid from the source liquid supply, said means disposed within the body, - at least one liquid purification means, - a drainage line in fluid communication with the liquid purification means, and - a liquid flow control system, characterized in that, in the liquid purification unit, the liquid flow control system is configured to maintain liquid pressure in the displacement cavity of the container above atmospheric pressure, and the liquid flow control system includes a source liquid feed section, a purified liquid feed section, and a source liquid distribution section, wherein the source liquid feed section comprises an inlet in fluid communication with the source liquid distribution section and an outlet in fluid communication with the liquid purification means, the purified liquid feed section comprises an inlet in fluid communication with the liquid purification means, a first outlet in fluid communication with the purified liquid feed line to the consumer, and a second outlet in fluid communication with the storage cavity for purified liquid, and the source liquid distribution section is configured to pass source liquid displaced from the displacement cavity to the source liquid feed section and to distribute and redirect flows of source liquid and purified liquid without using a hydro automatic unit, and wherein the source liquid distribution section comprises a contra-flow liquid flow arrangement which includes a recirculation line for source liquid, the recirculation line is connected at one end thereof with the displacement cavity for source liquid and at other end thereof with the source liquid supply and the inlet of the source liquid feed section; or a two-line arrangement in the form of a source liquid feed line to the displacement cavity and a source liquid displacement line from the displacement cavity, wherein the source liquid feed line has its inlet connected to the source liquid supply and its outlet connected to the displacement cavity, and wherein the source liquid displacement line has its inlet connected to the displacement cavity and its outlet connected to the source liquid feed section; and wherein the source liquid feed section further comprises a pressure increasing means that produces a pressure which is conveyed via the liquid purification means and the purified liquid feed section to the storage cavity for purified liquid, said pressure exceeding the pressure maintained in the displacement cavity. - a liquid-liquid type container consisting of a body and a means that defines a storage cavity for purified liquid and a displacement cavity for source liquid from the source liquid supply, said means disposed within the body, - at least one liquid purification means, - a drainage line in fluid communication with the liquid purification means, and - a liquid flow control system,