Niagara Conservation’s Nano Toilet uses vacuum- assist technology to achieve an average of 0.6 gallons per flush. WaterSense certified and MaP premium rated, the toilet is touted as one of the most water-efficient toilet fixtures on the market. The Nano’s compact design is ideal for tight spaces or tiny homes, the company says, while its elongated bowl preserves user comfort. The toilet also includes a noise-cancelling water tank and 10-year warranty. Prices are $204 for the Nano single flush and $214 for the double flush.