Introduction to Toilets

Toilets have been around for a very long time. Some reports that claim toilets have been in use as long ago as ancient Babylonia in the palace of Sargon the Great and in 2000, archaeologists discovered a 2000-year-old toilet in the tomb of a Han king in China.

Although in general, inventions get better and better over time, toilet functionality took a downswing after a 1992 federal law mandated that new household toilets use no more than 1.6 gallons (6.05 liters) of water per flush after January 1, 1994. This move, designed to conserve water, resulted in some inferior toilet designs in the first few years, as manufacturers tried to figure out how to adapt toilets that had used 3.5 (13.24 liters) or 5 gallons (18.92 liters) per flush. The result was a number of models with very poor performance and frequent clogs. But after several years of experimenting, the design of toilets has improved—though there is an inherent limit to the amount of waste the smaller tank can process. These recent innovations have improved their functionality.

Although the reduction in water usage was significant with the move to a 1.6 gallon limit—estimated as 14,000 gallons per year for a family of four—some manufacturers have gone even farther, introducing a dual-flush toilet that saves more water. These toilets offer a choice of flush volumes so that the user can choose. The general rate is 1.6 gallons for solid waste and .8 gallons (3.02 liters) for liquids.

There are three main ways that toilets work to flush waste: pressure-assist, vacuum-assist, and gravity.

• Pressure-assist toilets, (also called “pressure-assisted” toilets) with their enhanced flushing power, are the kind most often found in public restrooms. Featuring a tank-less design, they work by having water replace air in a sealed area so that the water pushes the waste from the bowl. But the great pressure used leads to another “feature” that may not be so desirable: they’re quite noisy. Another drawback is that the water pressure requirements are more than twice that of gravity toilets.
  
• Vacuum-assist toilets use a chamber to pull air out a trap area, allowing it to fill with water while clearing waste from the bowl. These toilets are quiet, but have significantly less flushing power than pressure-assist toilets.
  
• Gravity toilets are the most common type. A tank mounted above the bowl drops water into the bowl and trap to wash waste away. Requiring pressure as low as 10 pounds per square inch (68 947 pascals), these toilets can function in situations in which the water pressure is too low for pressure-assist toilets. And being the most common choice for a household—due to low water pressure requirements, quietness, and track record—they have the most models available.

Toilet bowls, made of vitreous china, come in two standard shapes: rounded and elongated. The rounded shape both saves space and works with a greater variety of seats. Toilets are also available in several heights, and there are three standard models:

• Two-piece toilets have a floor mount and a separate tank that are bolted together. They are less expensive to purchase than one-piece designs, but more difficult to keep clean.
  
• One-piece toilets include both the bowl and tank as a single element. They tend to be more compact than two-piece toilets, as well as easier to keep clean, but also more expensive.
  
• Wall-hung toilets are fastened to the wall and have no pedestal. The tank is contained within the wall, saving space in the room and making the flush quieter. This also contributes to easier cleaning.

Toilets are available individually and as part of bathroom suites and ensembles, in which they may be combined with bidets, sinks, baths, showers, faucet fixtures, toilet seats, whirlpools, and other items, all in coordinated style and colors.