Running water is often taken for granted. The amount of work needed to ensure that everyone has it tends to remain unnoticed until there is a drought. In most cases the water utility is also the sewage company. The same company will purify and supply drinking water, though also treat waste.
Some households are on their own as far as water supply is concerned. Such homes rely on a septic tank for waste treatment, which must be correctly installed and maintained. Most jurisdictions require that the tank be inspected regularly to ensure it is not leaking and that it be a certain distance from the home. For drinking water, a spring or well is generally relied on, with an electric pump.
Most households, however, are hooked up to the mains system. Tap water is supposed to be drinkable, although in some areas the taste can be questionable. Certain chemicals, such as fluorine and even chlorine are often added to drinking water. Because of this, bottled and distilled water are commonly purchased.
The water company manages reservoirs, drawing their supply from aquifers. In rare cases, desalination technology is used, a process during which salt is removed. Awareness of water as a limited resource has increased. Flat rates for water supply have been replaced by meters. This encourages users to conserve, collect rain and install greywater systems to recycle and reuse water. Companies are responsible for inspecting and maintaining what may be miles of pipes. The utility is responsible if water is not clean. They use a system of sedimentation, filtration and disinfection to purify the water.
Sewage treatment is designed to reduce pollution. It also relies on sedimentation, followed by aeration. Some plants are moving to an anaerobic treatment process that produces methane as fuel. Sewage pipe inspection is a major industry in large cities.