A bath bathtub (AmE), or tub (informal) is a plumbing fixture used for bathing. Most modern bathtubs are made of acrylic or fiberglass, but alternatives are available in enamel over steel or cast iron, and occasionally wood. A bathtub is usually placed in a bathroom either as a stand-alone fixture or in conjunction with a shower.
Modern bathtubs have overflow and waste drains and may have taps mounted on them. They may be built-in or free standing or sometimes sunken. Until recently, most bathtubs were roughly rectangular in shape but with the advent of acrylic thermoformed baths, more shapes are becoming available. Bathtubs are commonly white in colour although many other colours can be found. The process for enamelling cast iron bathtubs was invented by the Scottish born American David Dunbar Buick.
Two main styles of bathtub are common:
Clawfoot tubs come in 5 major styles:
Air bubbles may be introduced into the nozzles via an air-bleed venturi pump that combines cooler air with the incoming heated water to cool the pool if temperature rises uncomfortably high. Some spas have a constant stream of bubbles fed via the seating area of the pool, or a footwell area. This is more common as a temperature control device where the heated water comes from a natural (uncontrolled heat) geothermal source, rather than artificially heated. Water temperature is usually very warm to hot — 38°C to 42°C (100 to 104 °F). So bathers usually spend a short time inside, 20 to 30 minutes at 39°C. Bromine or mineral sanitizers are often recommended as sanitizers for spas because chlorine dissipates at a high temperature thereby heightening its strong chemical smell. Ozone is an effective bactericide and is commonly included in the circulation system with cartridge filtration, but not with sand media filtration due to clogging problems with turbid body fats.
Documented early plumbing systems go back as far as around 3300 BC with the discovery of copper water pipes beneath a palace in the Indus River Valley in India. Evidence of the first personal sized bath tub was found on the Isle of Crete where a long pedestal tub was found built from hardened pottery. This tub is the most likely forefather of the classic 19th century clawfoot tub.
The Roman Empire is most widely known as the early champions of bathing. Around 500 BC Roman citizens were encouraged to bathe daily in one of the many public baths. Private bathing rooms were far more ornate and typically would resemble shallow swimming pools that encompassed the entire room. The Romans used marble for the tubs, lead and bronze for pipes, and created a complex sewage system for sanitation purposes. The Roman empire set the early bar for modern personal hygiene.
Contrary to popular belief, bathing and sanitation were not a lost practice with the collapse of the Roman Empire. Soapmaking first became an established trade during the Early Middle Ages. Also, contrary to myth, chamberpots were not disposed of out the window and into streets in the Middle Ages - this was instead a Roman practice. Bathing in fact did not fall out of fashion until shortly after the Renaissance, replaced with the heavy use of sweat-bathing and perfume, as it was thought that water could carry disease into the body through the skin. Modern sanitation was not widely adopted until the 19th and 20th centuries.
The bathtub's modern spouse, the toilet, had problems gaining acceptance. Sir John Harington invented the first flushing toilet for himself and for his godmother, Queen Elizabeth I, in 1596. When Harington published a book describing his invention, he was roundly chided by peers, embarrassing him to the point of retirement from plumbing. His two toilets were the only ones he ever produced. The next water closet would not be seen for 200 years when it was introduced by Alexander Cummings in 1775. This event would mark the very beginnings of the modern bathroom.
It was now time for the piping to catch up with the fixtures. Until the 19th century, most water pipes in the US were made from hollow trees. In the early 1800s, cast-iron production began reducing American reliance on England for this material. Finally, in 1848, The National Public Health Act was passed in the US, creating a plumbing code for the first time.
In 1883, Standard Sanitary Manufacturing Company and Kohler Company began producing cast-iron bathtubs. Far from the ornate feet and luxury most associated with clawfoot tubs, an early Kohler example was advertised as a "horse trough/hog scalder, when furnished with four legs will serve as a bathtub." The item's use as hog scalder was considered a more important marketing point than its ability to function as a bathtub. Everyone knew what a hog scalder or horse trough was, but many people at that time had never bathed in a tub. The tubs eventually caught on because of the sanitary and easy-to-clean surfaces that prevent the spread of disease.
A few years later, Thomas Twyford created the first valveless toilet constructed from china. Before this time, toilets were normally made from metal and wood. Thomas Crapper would gain infamy as the inventor of the modern toilet when he bought the rights to a patent for a "Silent Valveless Water Waste Preventer", but he did not invent the toilet.
The bathing world was rocked by controversy when a completely inaccurate account of bathing and bathtub history was published by H.L. Mencken in 1917. What began as a light attempt at humor ended up being adopted by the public and even reputable publications. While perhaps good reading, Mencken's account of laws prohibiting bathing, and much more, is not true.
The end of World War I resulted in a housing construction boom in the United States and a new conception of the purpose-built modern bathroom. Bathrooms prior to World War I were typically converted bedrooms or spare rooms, not rooms built originally to contain bathroom fixtures. Complete with toilet, sink, and tub, the modern bathroom was a feature of 100% of new homes by the end of the 20th century, whereas only 1% of homes had had bathrooms in 1921.
In the latter half of the 20th century, the once popular clawfoot tub morphed into a built-in tub with a small apron front. This enclosed style afforded easier maintenance and, with the emergence of colored sanitary ware, more design options for the homeowner. The Crane Company introduced colored bathroom fixtures to the US market in 1928, and slowly this influx of design options and easier cleaning and care led to the near demise of clawfoot-style tubs.