Items 1 - 10 of 10 Buy great products from our Universal Toilet Cisterns Category online at Wickes. artdetoilette.com We supply trade quality DIY and home improvement. A cistern is a waterproof receptacle for holding liquids, usually water. Cisterns are often built to catch and store rainwater. Cisterns. Dual flush 4/2L WC cistern with side inlet for compact back to wall Rimless toilet. > The Gap. x x Dual flush 4,5/3L WC cistern with.