 Sophisticated water engineering was used at Cîteaux Abbey, Roche Abbey and the Carmelite Desierto de Los Leones in Mexico to ensure both that these rooms remained fresh and that the effluent did not pollute water needed for cooking and washing.There appear to have been as many seats as there were monks, separated by screens, and each with a window.In some monasteries there were two reredorters, one for the monks and one for the lay brothers.