When shopping in the bowls and tank categories, you must purchase a bowl, a tank, and a toilet seat to create a complete toilet. Look at the advanced specifications for each product for more details.Purchasing GuideToilets have two basic operational elements: (1) the intake of water used for flushing and (2) the discharge of waste water. However, there are different types of toilets based on the way they perform these operations. You need to identify which type(s) of toilets are currently in your building and which is the most appropriate type to replace them with before you make a purchased. Gravity Tank Toilets: Gravity tank toilets, which have a bowl and a tank, are most commonly found in residential settings but are in some commercial/business settings. They depend on the volume of water in the tank to flush wastes and usually require water pressure of no more than 10 - 15 pounds per square inch (psi) to operate properly. The tank and bowl are usually two separate pieces, although this is not obvious once are in use. A few one-piece toilets are also available. Gravity tank toilets are relatively inexpensive, with retail prices for two-piece toilets ranging from $75 - $150 and one-piece models costing somewhat more. Pressurized Tank Toilets: This relatively new design uses water line pressure to achieve a higher flush velocity. Water is not stored inside the tank, but in a tank that compresses a pocket of air and releases pressurized water into the bowl and