You definately can buy rubberized incontinence sheets (various sizes) from a hospital supply store. We had them for my father and they were about $25 each in Canada but we only needed three, one on the bed, on in the wash and a spare. My mother also used a pessary inserted by her doctor that helped keep her bladder in place and stopped leaking. In addition to the small waterproof sheets we also had a waterproof mattress cover that saved us from many disasters.