SPECIAL ORDER ITEM. Review Returns Policy before purchase. With its clean, simple design and efficient performance, this Kohler Highline water-conserving toilet combines both style and function. An innovative 1.28-gallon flush setting provides significant water savings of up to 16,500 gallons per year, compared to an old 3.5-gallon two-piece elongated toilet, without sacrificing flushing power. This model features a unique tank liner that minimizes exterior condensation in humid environments.