Forget 1.6-gallon-per-flush toilets. You can even dismiss 1.28-gallon units. This all-in-one, high-efficiency toilet uses only 1 gallon of water per flush. The Water Sense–certified unit handles twice the average solid waste with a single flush and comes in a round- or an elongated-bowl configuration. Cost: $295 to $349. Foremost Groups. 800-443-1410. www.foremostgroups.com.