The present invention relates to methods for fabrication or modification of polymer membranes for water treatment utilizing ink-jet printing. The methods of the invention provide substantial advantages over the current state of the art including, inter alia, accurately delivering precise amounts of liquids to surfaces; quickly changing coating parameters; quickly controlling and changing coating compositions; and tailor-making membranes according to customer needs. The membranes fabricated or modified according to these methods have improved antifouling properties.