Security

Massive breach fuels calls for US action on cybersecurity

Jolted by a sweeping hack that may have revealed government and corporate secrets to Russia, U.S. officials are scrambling to reinforce the nation's cyber defenses and recognizing that an agency created two years ago to protect ...

Engineering

Contextual engineering adds deeper perspective to local projects

When engineers develop drinking water systems, they often expect their technology and expertise to work in any context. But project success depends as much on the people and place as on technical design, says Ann-Perry Witmer, ...

Energy & Green Tech

Harnessing the sun to purify concentrated waste streams

Reverse osmosis is one of the most common methods for purifying saline water, but the process produces limited results. About 20% to 50% of the water that enters the system remains as a concentrated waste stream.

page 5 from 8

Tap water

Tap water (running water) is part of indoor plumbing, which became available in the late 19th century and common in the mid-20th century.

The provision of tap water requires a massive infrastructure of piping, pumps, and water purification works. The direct cost of the tap water alone, however, is a small fraction of that of bottled water, which can cost from 240 to 10,000 times as much for the same amount.

The availability of clean tap water brings major public health benefits. Usually, the same administration that provides tap water is also responsible for the removal and treatment before discharge or reclamation of wastewater.

In many areas, chemicals containing fluoride are added to the tap water in an effort to improve public dental health. This remains a controversial issue in the health, freedoms and rights of the individual. See water fluoridation controversy.

Tap water may contain various types of natural but relatively harmless contaminants such as scaling agents like calcium carbonate in hard water and metal ions such as magnesium and iron, and odoriferous gases such as hydrogen sulfide. Local geological conditions affecting groundwater are determining factors of the presence of these substances in water.

Occasionally, there are health concerns regarding the leakage of dangerous biological or chemical contaminating agents into local water supplies when people are advised by public health officials not to drink the water, and stick to bottled water instead. An example is the recent discovery of potentially hazardous nitrates in the public water supply in Phoenix, Arizona.

This text uses material from Wikipedia, licensed under CC BY-SA