Soaking tubs are good choices for small bathrooms or for people who like to be deeply immersed in water. Also known as Japanese, Asian or Greek tubs, they are traditionally about 4 feet long, compared with about 5 feet for a standard tub, and are usually 26 to 34 inches deep, compared with 14 to 16 inches for conventional tubs. There are round versions as well, which are usually about 40 inches in diameter.
Like conventional bathtubs, soaking tubs are made of many materials -- from acrylic to metal to stone. Traditional Japanese soaking tubs are made of wood, and you can also buy freestanding soaking tubs with wood exteriors and acrylic or fiberglass interiors. Soaking tubs tend to be much more expensive than conventional tubs -- usually a minimum of $1,400 uninstalled and frequently $5,000 or $6,000. Some fancy soaking tubs have whirlpool features.
Almost all major manufacturers of bathtubs have entered this market, including Kohler, American Standard and Jacuzzi. Companies that make conventional bathtubs sometimes offer soaking tubs that are of a standard U.S. length -- in other words, about a foot longer than a traditional Japanese- or Greek-style tub. If you have back problems, you might want to consider that deeper tubs will require more bending while you're scrubbing them.