Title: Toilet
Content:  its currently known form, with an overhead cistern, s-bends, soil pipes and valves around 1770. This was the work of Alexander Cumming and Joseph Bramah. Water closets only started to be moved from outside to inside of the home around 1850. The integral water closet started to be built into middle-class homes in the 1860s and 1870s, firstly on the principal bedroom floor and in larger houses in the maids' accommodation, and by 1900 a further one in the hallway. A toilet would also be placed outside the back door of the kitchen for use by gardeners and other outside staff such as those working with 
Title: Toilet
Content:  by the privy midden and pail closet in early industrial Europe. In the early 19th century, public officials and public hygiene experts studied and debated sanitation for several decades. The construction of an underground network of pipes to carry away solid and liquid waste was only begun in the mid 19th-century, gradually replacing the cesspool system, although cesspools were still in use in some parts of Paris into the 20th century. Even London, at that time the world's largest city, did not require indoor toilets in its building codes until after the First World War. The water closet, with its origins in Tudor times, started to 
Title: Toilet (room)
Content:  the outhouse included the privy midden and the pail closet. Indoor toilets were at first a luxury of the rich and only gradually spread to the lower classes. As late as the 1890s, building regulations in London did not require working-class housing to have indoor toilets; into the early 20th century, some English homes were built with an upstairs toilet for use by the owners and an outhouse for use by the servants. In some cases, there was a transitional stage where toilets were built into the house but accessible only from the outside. After World War I, all new housing in London and its suburbs had indoor toilets. Bathrooms became standard later than toilets, but entered working-class houses at around the same 
Title: Toilet
Content:  prosperity, that the flush toilet became a widely used and marketed invention. This period coincided with the dramatic growth in the sewage system, especially in London, which made the flush toilet particularly attractive for health and sanitation reasons. Flush toilets were also known as "water closets", as opposed to the earth closets described above. WCs first appeared in Britain in the 1880s, and soon spread to Continental Europe. In America, the chain-pull indoor toilet was introduced in the homes of the wealthy and in hotels in the 1890s. William Elvis Sloan invented the Flushometer in 1906, which used pressurized water directly from the supply line for faster recycle time between flushes.
Title: Flush toilet
Content:  Although flush toilets first appeared in Britain, they soon spread to the Continent. The first such examples may have been the three "waterclosets" installed in the new town house of banker Nicolay August Andresen on 6 Kirkegaten in Christiania, insured in January 1859. The toilets were probably imported from Britain, as they were referred to by the English term "waterclosets" in the insurance ledger. Another early watercloset on the European continent, dating from 1860, was imported from Britain to be installed in the rooms of Queen Victoria in Ehrenburg Palace (Coburg, Germany); she was the only one who was allowed to use it. In America, the chain-pull indoor toilet was introduced in the homes of the wealthy and in hotels, soon after its invention in England in the 1880s. Flush toilets were introduced in the 
Title: Public toilet
Content:  Older toilets infrequently have service ducts and often in old toilets that have been modernized, the toilet cistern is hidden in a tiled over purpose-built 'box'. Often old toilets still have high-level cisterns in the service ducts. On the outside, the toilet is flushed by a handle (just like an ordinary low-level cistern toilet) although behind the wall this handle activates a chain. Sometimes a long flushing trough is used to allow closets to be flushed repeatedly without waiting for the cistern to refill. This trend of hiding cisterns and fittings behind the walls started in the late 1930s in the United States and in the United Kingdom from the 1950s, and by the late 1960s it was unusual for toilet cisterns to be visible in public toilets. In some buildings such as schools, however, a cistern can still be visible, although high-level cisterns had become outdated by the 1970s. Many schools now have low-level cisterns.
Title: Public toilet
Content:  In the United States, concerns over public health and sanitation spurred the sanitarian movement during the late 1800s. Reforms to standardize plumbing codes and household plumbing were advocated for; the intersection of advancements in technology and desire for cleanliness and disease-free spaces spurred the development of public toilets. Facilities for women sometimes had a wider emphasis, providing a safe and comfortable private space in the public sphere. The Ladies Rest Room is one example of the non-euphemistic use of the term: literally, a place to rest. Historically such rooms pre-dated the washroom and washrooms were added afterwards. Subsequent integrated designs resulted in the "women's restroom lounge". A 
Title: Hygiene
Content:  took decades for his findings to gain wide acceptance, governments and sanitary reformers were eventually convinced of the health benefits of using sewers to keep human waste from contaminating the water. This encouraged the widespread adoption of both the flush toilet and the moral imperative that bathrooms should be indoors and as private as possible. Modern sanitation was not widely adopted until the 19th and 20th centuries. According to medieval historian Lynn Thorndike, people in Medieval Europe probably bathed more than people did in the 19th century. Some time after Louis Pasteur's experiments proved the germ theory of disease and Joseph 
Title: Flush toilet
Content:  It was only in the mid-19th century, with growing levels of urbanisation and industrial prosperity, that the flush toilet became a widely used and marketed invention. This period coincided with the dramatic growth in the sewage system, especially in London, which made the flush toilet particularly attractive for health and sanitation reasons. George Jennings established a business manufacturing water closets, salt-glaze drainage, sanitary pipes and sanitaryware at Parkstone Pottery in the 1840s, where he popularized the flush toilet to the middle class. At The Great Exhibition at Hyde Park held from 1 May to 15 October 1851, George Jennings installed his Monkey Closets in the Retiring Rooms of The Crystal Palace. These were the 
Title: Public toilet
Content:  Public toilets were part of the sanitation system of ancient Rome, often in proximity to or as part of public baths (thermae). By the Middle Ages public toilets became uncommon, with only few attested in Frankfurt in 1348, in London in 1383, and in Basel in 1455. A public toilet was built in Ottoman Sarajevo in 1530 just outside a mosque's exterior courtyard wall which is still operating today. In the early 19th century, large cities in Europe started installing public toilets: first in Paris, then in Berlin in 1820 and in London in 1851. George Jennings, the sanitary engineer, introduced public toilets, which he called "monkey closets", to the Crystal Palace for The Great Exhibition of 1851. Public toilets were 

Question: when did indoor toilets become common in america?
Answer: After World War I.