engineering

Tap water

Tap water is a engineering topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Tap water rather than just read about it. In short: Tap water (also known as running water, piped water or municipal water) is water supplied through a tap, a water dispenser valve. In many countries, tap water usually has the quality of drinking water.

Key takeaways

Tap water belongs to engineering; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Tap water to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Tap water from memory before moving on to harder problems.

Reference excerpt

Tap water (also known as running water, piped water or municipal water) is water supplied through a tap, a water dispenser valve. In many countries, tap water usually has the quality of drinking water. Tap water is commonly used for drinking, cooking, and washing. Indoor tap water is distributed through indoor plumbing, which has been around since antiquity but was available to very few people until the second half of the 19th century when it began to spread in popularity in what are now developed countries. Tap water became common in many regions during the 20th century, and is now lacking mainly among people in poverty, especially in developing countries. Governmental agencies commonly regulate tap water quality. Calling a water supply "tap water" distinguishes it from the other main types of fresh water which may be available; these include water from rainwater-collecting cisterns, water from village pumps or town pumps, water from wells, or water carried from streams, rivers, or lakes (whose potability may vary).

Terminology A synonym for tap water is piped water, a term used by the Joint Monitoring Programme (JMP) for Water Supply and Sanitation by WHO and UNICEF to describe the situation for access to drinking water in developing countries. Piped water is not necessarily of drinking water quality but does count as an "improved water source" in the logic of Sustainable Development Goal 6. Other improved water sources include boreholes, protected dug wells or springs, rainwater, and bottled or water delivered by tanker.

Fixtures and appliances

Everything in a building that uses water falls under one of two categories; fixture or appliance. As the consumption points above perform their function, most produce waste/sewage components that will require removal by the waste/sewage side of the system. The minimum is an air gap. See cross connection control & backflow prevention for an overview of backflow prevention methods and devices currently in use, both through the use of mechanical and physical principles. Fixtures are devices that use water without an additional source of power.

Fittings and valves

Potable water supply systems are composed of pipes, fittings, and valves.

Water flow reduction

Water flow through a tap can be reduced by inexpensive small plastic flow reducers. These restrict flow between 15 and 50%, aiding water conservation and reducing the burden on both water supply and treatment facilities.

Materials

The installation of water pipes can be done using the following plastic and metal materials:

Plastic polybutylene (PB) high density cross-linked polyethylene (PE-X) block copolymer of polypropylene (PP-B) the polypropylene copolymer (PP-H) random copolymer of polypropylene (random) (PP-R) Layer: cross-linked polyethylene, aluminum, high-density polyethylene (PE-X / Al / PE-HD) Layer: polyethylene crosslinked, aluminum, cross-linked polyethylene (PE-X / Al / PE-X) Layer copolymer of a random polypropylene, aluminum, polypropylene random copolymer (PP-R / Al / PP-R) polyvinyl chloride, chlorinated (PVC-C) polyvinyl chloride - not softened(only cold water) (PVC-U)

Metals carbon steel, ordinary galvanized corrosion resistant steel Deoxidized High Phosphorus copper (Cu-DHP) lead (no longer used for new installations due to its toxicity) Other materials, if the pipes made from them have been let into circulation and the widespread use in the construction of the water supply systems.

Lead pipes For many centuries, water pipes were made of lead, because of its ease of processing and durability. The use of lead pipes was a cause of health problems due to ignorance of the dangers of lead on the human body, which causes miscarriages and high death rates of newborns. Lead pipes, which were installed mostly in the late 1800s in the US, are still common today, much of which are located in the Northeast and the Midwest. Their impact is relatively small due to the fouling of pipes and stone cessation of the evolution of lead in the water; however, lead pipes are still detrimental. Most of the lead pipes that exist today are being removed and replaced with the more common material, copper or some type of plastic.

Distribution systems and contamination

Modern plumbing delivers clean, safe, and potable water to each service point in water distribution system, including taps. It is important that the clean water not be contaminated by the wastewater (disposal) side of the process system. Historically, this contamination of drinking water has been one of the largest sources of human fatalities. Most of the mandates for enforcing drinking water quality standards are not for the distribution system, but for the treatment plant. Even though the water distribution system is supposed to deliver the treated water to the consumers' taps without water quality degradation, complicated physical, chemical, and biological factors within the system can cause contamination of tap water. If fecal indicator bacteria are found, it indicates that the water source may have been contaminated with fecal matter and requires treatment. The movement of water to consumers may require several hours or even days, leading to what is known as “water age.” This age represents the system’s hydraulic retention time, variations in water consumption, and the size and complexity of the distribution network. Tap water can sometimes appear cloudy and is often mistaken for mineral impurities in the water. It is usually caused by air bubbles coming out of solution due to change in temperature or pressure. Because cold water holds more air than warm water, small bubbles will appear in water. It has a high dissolved gas content that is heated or depressurized, which reduces how much dissolved gas the water can hold. The harmless cloudiness of the water disappears quickly as the gas is released from the water.

Water supply

Comparison to bottled water

Preferences for tap versus bottled water are mostly guided by taste, perceived safety, and personal habits. Negative sensory traits in tap water—such as bad taste or odor—encourages higher bottled water consumption. Plastic bottled water consumption has continued to rise, even in regions with high-quality tap water. This growth contributes to environmental issues such as transportation emissions and buildup of non-degradable plastics.

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with Tap water

Start with the simplest possible case. Write down what Tap water claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In engineering, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Tap water before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Tap water ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Tap water

In research: Tap water appears in engineering research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Tap water in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Tap water is common in secondary-school and first-year university syllabi. It links to neighbouring topics Drinking water, Water, Water pollution, so understanding it makes those chapters shorter.
In everyday life: Look for Tap water outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Tap water in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Tap water means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Tap water out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Tap water in simple terms?

Why does Tap water matter?

Because it connects several engineering ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Tap water?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Tap water.