A permanent, reuseable liquid filter comprises a thin flexible filter material (A) and a support skeleton (B) secured to the outside surface thereof. The skeleton includes a centrally disposed support rim (20) and a plurality of support rib sets (22) spaced around and extending outwardly from the support rim. Each rib set comprises a plurality of separate elongated ribs (24, 26, 28) extending from adjacent the support rim toward the filter material outer edge (14) with the ribs of each set being connected together by a first connecting web (34). A second connecting web (36) may be advantageously used to connect each support rib set to the support rim. The filter, when not in use, is normally in a generally flat condition as shown and automatically assumes the general shape of a filter basket or other support structure (not shown) upon installation thereinto. The support rim then generally defines a filter bottom area with the ribs (24, 26, 28) urging the remainder of the filter material (A) towards engagement with the filter basket or support structure side wall area. Any necessary filter material folds, pleats or flutes required to accommodate folding from the generally flat condition are formed between adjacent support rib sets (22) and extend generally coextensively therewith.