A method and system for treating oilfield produced water is disclosed. The method includes passing oilfield produced water through a chain of filters, first filter configured to filter particles of a size larger than 10 m from the water, a second filter configured to filter remaining particles of a size larger than 2 m from the water and a third filter configured to filter remaining particles of a size larger than 0.5 m from the water and automatically cleaning at least one of the filters.