A. ULF toilets use only 1.6 gallons per flush (gpf) or less, compared to older toilets that use 3.5 to 7 gpf. If your toilet was manufactured in the 1970s or before, it uses between 5 and 7.5 gpf. The older your toilet, the more water it probably uses. If your toilet was manufactured after 1980, it uses 3.5 gpf, unless it is a newer 1.6 gpf or less ULF toilet. Studies done at various places around the country show that toilets account for approximately 30 percent of all household water use.

A.  An average household of 2.64 persons replacing older 5 gpf toilets would save 45.8 gallons per day or about 16,709 gallons per year. This would amount to an annual utility bill savings of more than $200, depending on where you live.

A.  There are three basic types: gravity, pressure assisted, and vacuum assisted.

Gravity-flush toilets use the same principles as other toilets that have been in use for decades. However, the rim wash may come through an open slot rather than little holes, and the bowl may have steep sides and a narrower trapway. The design changes of these toilet bowls cause a quick release of water, creating a siphon action to pull waste out.

Pressure-assisted toilets use the water pressure in the line to increase velocity of water going to the bowl. Within the tank incoming water presses against a rubber diaphragm that compresses a pocket of air. The water is released when the toilet is flushed.

Vacuum-assisted toilets use a vacuum force which draws the water with more force into the bowl. Currently, these toilets are only available from Briggs.

A.  Ask a plumber or a plumbing supply store for a recommendation on which model they have had the most satisfaction with. Also, before you make a purchase, make sure it can be replaced or returned if you are not happy with it after it is installed. Remember, the old adage is usually true – you get what you pay for. You may be asking for trouble if you buy a cheap import or no-name model (usually under $50) sold at building supply stores. Also, remember, to be eligible for the rebate, the toilet you select must be on the listing of approved ultra low-flush toilets.

A.  Generally, yes.  However, "as well" differs from person to person. Most of today’s high efficiency toilets have been carefully engineered to clean the bowls and move waste using a small amount of water. But, as with any consumer product, some models work better than others, and it is always a good idea to do a little research before you buy anything. If an ultra low-flush toilet bears the "ANSI" seal of approval, it means it has passed a series of performance tests by the American National Standards Institute. You can find more information at the U.S. Environmental Protection Agency's EPA's WaterSense web site.

A.  One reason is that early models were poorly designed and some of these are still around. In addition, you can still buy models that perform poorly though you have to try hard now to find one from a major manufacturer. Sometimes, people naturally operate under the assumption that if one didn’t perform well, they’re all bad. But this notion simply isn’t true. Shop for a toilet just like you would for any other appliance. Don’t blame the whole industry for the problems of a few poorly made models. With manufacturers continually updating and improving the performance of their models, many customers find that their new toilets actually flush better that their old high-volume models.

A.  Many models are available from $75 - $200, and can run $400 and higher for one-piece decorator models.

A.  Not usually. The basic white model probably performs as well as any other model from the same manufacturer.

Some gravity 1.6 gpf toilets have standard tank parts that are easy to find and replace. Other 1.6 gpf gravity toilets and all the pressure-assisted and vacuum-assisted toilets have specialized parts that may be difficult or expensive to replace.

Plumbers generally charge $50 - $90 to replace a toilet if there are no other problems. If you are going to hire a plumber, get a written estimate before the work begins. As with any work, it is better to get two or three estimates.