A method of treating a liquid the method including: receiving a chemically treated liquid； passing the chemically treated liquid through a nanobubble generator to produce a nanobubble containing liquid； treating the nanobubble containing liquid with disinfecting radiation to produce a resultant liquid； and releasing the resultant liquid for use. A liquid treatment system including: a source of liquid； a chemical treatment station to test the chemical content of the source liquid and if necessary provide an appropriate amount of chemical treatment to the liquid to provide a chemically treated liquid； a nanobubble generator in fluid communication with the chemical treatment station that generates nanobubbles to provide a nanobubble liquid； a radiation based disinfecting unit (RDU) in fluid communication with the nanobubble generator that exposes the nanobubble liquid to radiation and provides treated liquid； a pump to produce a liquid flow through the system； and an outlet through which the treated liquid flows.
