Invention

Part 17 - Toilets

The earliest evidence of toilets comes from northwestern India and Pakistan about 2800 BCE. Around 2350 BCE, citizens of Lothal had their own private toilets with flowing water to removed human waste through a network of sewers.

Between 3100 and 2500 BCE, residents of Orkney, Scotland used flowing water to remove the waste through drain running directly under their houses. After 1800 BCE, toilets came into use in Crete, Egypt, and Persia (Syria and Iran). 

The Romans used flowing water in public bath houses to flush latrines but Gaius Plinius Secundus (23 to 79 CE) described large receptacles in the streets of Rome and Pompeii into which chamber pots of urine were emptied. The urine was then collected for leather and textile manufacture.

By the 16th century in Europe, as urban populations grew and street gutters became blocked with the larger volume of human waste, rain was no longer sufficient to wash away the sewage. People dug cesspits and cesspools near houses to collecting waste. In some places, a pipes connected latrines to the cesspool, and sometimes a small amount of water flushed waste through. Cesspools were cleaned out by men, known in England as gong farmers, who pumped out liquid waste, then shovelled out the solid waste and collected it during the night. This solid waste, euphemistically known as nightsoil, was sold as fertilizer for agricultural production.

In 1596, Sir John Harington had a flush toilet build for Queen Elizabeth I's palace in England. One flush used 7.5 Imperial gallons (34 L) of water. 

But it was 1775 before Alexander Cumming, and Joseph Bramah applied for a British patent for a flush toilet with an overhead water tank and an S-shaped pipe beneath the toilet bowl. The water in the S-bend prevented sewer gas from escaping.

Until the 19th century, most indoor toilets typically consisted of a wooden commode, known as a thunderbox, enclosing a chamber pot that was emptied into the gutter of the street nearest to the home.

The flush toilet was not commonly installed inside homes until the 1850's. The rate of adoption varied, but by 1906, Rochdale, a predominantly working class town in Britain, had 750 water closets for a population of 10,000.

Following the Big Stink of 1858, public hygiene experts finally convinced the British government to build a sewage collection and treatment system in London. A comprehensive network of underground sewers was built to move solid and liquid waste to treatment plants. These gradually replaced the cesspool system. But even then, London, at that time the world's largest city, did not require indoor toilets in its building codes until 1918.

Around 1880, Thomas Crapper mass produced an improved version of Alexander Cumming's design and he was often considered the inventor of the flush toilet. The slang term "crapper" for toilet was coined by American soldiers in England.

About the same time, Henry Doulton, George Jennings, Edward Johns, and Thomas Twyford all improved the flush toilet adding a tank that emptied with a siphon and automatically refilled with a float controlled valve to shut off the water when the tank was full. 

Flush toilets, also known as "water closets" (WC's), as opposed to earth closets, soon spread to continental Europe and, 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.

Most toilets made between the 1980s and early 90s typically use 3.5 U.S. gallons (13 L) per flush.  The U.S. Energy Policy Act required all toilets made and installed after 1994 to use a maximum of 1.6 (6 L) GPF (gallons per flush).

High-efficiency toilets use less than 1.3 gallons (5 L) of water per flush. Dual-flush toilets provide the option of a partial flush or full flush to clear waste. Most dual flush toilets use only 0.8 GPF (3 L) for a partial flush and 1.1 GPF (4 L).

In arid areas where water is very expensive, flushing toilets can be plumbed to use greywater (previously used for washing dishes, laundry, and bathing) rather than potable water (drinking water). Some modern toilets pressurize the water in the tank so that the flushing action uses less water.

A vacuum toilet, typically used on larger ships, is a flush toilet that is connected to a vacuum sewer system, and removes waste by suction. These may use less than a quarter of a liter per flush (or none in waterless urinals). Some flush with coloured disinfectant solution rather than with water.

Passenger train toilets, aircraft lavatories, bus toilets, and ships with plumbing often use vacuum toilets. The lower water usage saves weight, and avoids water slopping out of the toilet bowl in motion. Vehicles are equipped with holding tanks that must be pumped out periodically. 

Marine toilets used on small boats are often hand pumped using sea water to flush. In harbours or in inland fresh water the sewage is pumped into a holding tank for later disposal.

Dry toilets do not use water as an odor seal or to flush excreta along. These range from a simple 'honey bucket', a pit latrine (a deep hole in the ground. When full, a fruit tree may be planted on top to take advantage of the natural fertilizer), a vault toilet (the waste is stored in an underground tank until it is pumped out), a composting toilet (which mixes excreta with carbon-rich materials for faster decomposition. In China, wood ash was often used to reduce odours), a urine-diverting dry toilet (which keeps urine separate from feces), and incinerating and freezing toilets.

Portable toilets are used on construction sites and large outdoor gatherings where there are no other facilities. They are typically lightweight, self-contained units that are easily transported by truck. 

Today, 1 billion people in developing countries have no toilets in their homes and must defecate in the open instead. This results in waterborne diseases, including Cholera which still affects some 3 million people each year. 

One of the targets of the United Nations, Sustainable Development Goal number 6 is to provide toilets to everyone by 2030.

"High-tech" toilets, which are used in Japan, include features such as automatic-flushing mechanisms; water jets or "bottom washers"; blow dryers, or artificial flush sounds to mask noises. Some toilets have automatic lid operation, heated seats, deodorizing fans, or automated replacement of paper toilet-seat-covers.

Astronauts on the International Space Station use a space toilet with urine diversion which can recover potable water. Solid waste may also be desiccated to conserve water.

Euphemisms for toilets include 'bathroom, loo, lav and WC' in Britain, 'restroom' in America and 'washroom' in Canada.

The British term, 'Loo' may be a corruption of French, 'gare à l'eau' (look out for the water) as a warning when a chamber pot was about to emptied from a upper-story window onto the street. Or, 'lieu' (place) as in 'lieu d'aisance' (place of ease).   The Spanish word for toilet is, 'inodoro' which also translates as odourless.