DIY: How to choose a high efficiency toilet

| by Teena Hammond

Toilets amount to a significant amount of household water usage, accounting for up to 30 percent of indoor water use.

A family of four with standard pre-1994 toilets that use up to 3.5 gallons per flush, will use approximately 27,500 gallons of water a year. Switching to a high-efficiency toilet will cut back drastically on water usage. Conversion to 1.6-gallons-per-flush toilets will save 14,000 gallons. And dual-flush toilets will cut water use to about 10,000 gallons — an annual savings of more than 17,000 gallons.

High-efficiency toilets fit into these categories:

  • Single-flush, at 1.6 gallons per flush (gpf)
  • Dual-flush, with 1.6 gpf/0.8 gpf
  • Pressure-assist, with 1 gpf

Single-flush toilets using 1.6 gpf are required by code in most new home construction and bathroom remodeling jobs. They require, as the name implies, a single flush for solid and liquid waste.

Dual-flush toilets provide two flushing options. Solids are flushed using 1.6 gallons of water and liquids are flushed at 0.8 gpf.

Pressure-assist toilets are often used in commercial applications. This toilet consists of a plastic pressure tank mounted inside the toilet tank that uses pressure from the water supply line to compress air inside the pressure tank.

Ultra high-efficiency toilets are a new entry into the market, with Niagara Conservation developing the only 0.8 gpf toilet that eliminates solid waste. It harnesses air and water pressure to create a powerful, yet quiet, one-flush system. It retails for $308 online.

The top-selling brands include Kohler, Toto, Gerber and American Standard. In most areas, it costs about $450, including the fixture, to install a high-efficiency single-flush toilet. Including installation, dual-flush models can run up to $800. Toilet installation alone runs about $200.

Plumbing associations have put high-efficiency toilets to the test and developed a rating system for flush capacity. The results are part of the U.S. Environmental Protection Agency's WaterSense list of toilets, which must flush at 1.28 gpf or less.

According to the EPA, WaterSense toilets can save consumers more than $90 a year on water bills, and an average of $2,000 or more during the 10-year lifetime of the product.

Japan-based Toto has come up with such innovations as a concave, rather than hollow, rim around the bowl and double cycle flush engines. This creates a stronger flow. The most popular model is the UltraMax II, priced at about $350. This uses less water and requires less cleaning.

Another Toto innovation is the Washlet, a remote-controlled heated toilet seat that combines bidet and dryer in one, making toilet paper unnecessary. The Washlet is priced at $750.

Rebates and incentives are set by local and state governments, and vary widely. Those offered by WaterSense partners are listed on the EPA website.

For more information, see our Water Saving Devices Research Center.

Topics: Sinks & Toilets, Water Saving Devices

Companies: TOTO, Kohler

Teena Hammond
Teena Hammond has published more than 2,000 articles in People and W magazines, Women's Wear Daily, and in dozens of newspapers and books. She also wrote a home improvement, remodeling and decor column that ran in Gannett newspapers nationwide. She's interested in all things green and would love to hear from you with your story ideas.

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