Breaking down the different types of drinking water, from alkaline to sparkling

Distinguishing club soda, seltzer, and sparkling water

The three forms of drinking water are similar, but their differences lie mostly in the presence and proportion of minerals and carbonation. Read this quick explainer on the major differences.

The Safe Drinking Water Act protects tap water for Americans

Passed in 1974, the Safe Drinking Water Act requires the EPA to set and enforce national standards for public water systems. It regulates contaminants, funds infrastructure improvements, and ensures that communities nationwide have access to safe and clean drinking water.

View a map of countries with the safest and most dangerous drinking water

More than a quarter of the world's population lives in water-stressed countries, and a similar number use contaminated drinking water sources, which can lead to widespread disease, according to the World Health Organization. The Environmental Performance Index shows which countries have safe drinking water.

Bottled water started as a 19th-century wellness trend

Selling drinking water in America began at resorts in New York and West Virginia, where tourists were encouraged to take the regenerative mineral water back to their homes.

Forever chemicals are so common that experts concluded in 2022 that it's uncertain whether limiting consumer exposure would truly reduce one's exposure to these substances, and noted it would still take years for the body to clear them.

Pure water does not conduct electricity because this flow of energy requires the movement of charged particles, and water is a neutral molecule.

Many chemicals used in fracking fluid have been classified as toxic

Although the fluid has been known to leach into drinking water supplies, raising health concerns, fracking is exempt from federal clean water regulations due to a loophole in the Energy Policy Act of 2005 championed by former US Vice President Dick Cheney.

The Office of Water protects the nation's rivers, lakes and drinking supplies

The office develops national standards for safe drinking water, regulates wastewater treatment, and enforces the Clean Water Act. It partners with states and tribes to monitor pollution, protect wetlands, and restore aquatic ecosystems across the United States.

Explore this interactive EPA map, which shows 'forever chemical' testing results for public water systems—with brown spots indicating testing results above national limits.

How often should you clean your water bottle?

Experts say a daily wash of a high-use bottle is key to keep away unwanted bacteria and odors. For a good clean, use water—as hot as 140 degrees Fahrenheit—mixed with soap, swirling the mixture in the bottle before letting it sit for 20 minutes. Learn more tips with this quick overview.

Why bacterial bioremediation may help counter the negative effects of past chemical solutions

Molecules such as DDT, a synthetic insecticide, and PFAS—"forever" chemicals used to make products resistant to heat, water, and grease—have historically been used across various industries but are now known to be harmful. Microbes that can convert some of these substances into nontoxic products, such as water and carbon dioxide, have already been identified, with ongoing research to find others.

Breaking down the challenges of alkaline environments and how extremophiles survive them

These areas are far less acidic than the interiors of most organisms' cells, and this imbalance draws protons that are needed for various metabolic processes, including energy production, out of cells. To counter these effects, some alkaliphiles have developed stronger proton regulation across their cellular membranes and proteins that drive these processes with greater stability amid such acidity imbalances.

Although PFAS, or forever chemicals, are intentionally designed to be extremely stable and long-lasting because of their strong carbon-fluorine bonds, these bonds can be broken by heat, plasma, and supercritical water.

Explore an interactive map of global water gaps, caused by human consumption surpassing the rate at which water reserves are replenished by the hydrologic cycle.

Some faucets in regions near fracking wells run flammable water

A 2011 study found methane contamination as much as 3,000 feet away from wells, although there was no evidence of fracking chemicals in tested wells. Water with low methane concentrations is not harmful to drink, but it becomes flammable when mixed with air.

On a cruise ship, the average person uses about 50 gallons of water a day, which is treated by bacteria and onboard filtration systems, then stored until the ship can legally discharge the wastewater.

The Clean Water Act became the national standard for protecting American waters

Enacted in 1972, the Clean Water Act grants the Environmental Protection Agency the authority to regulate pollutant discharges, establish water quality standards, and oversee water pollution controls. Its scope has narrowed due to recent Supreme Court rulings.

A chemical overview of water, whose uncommon properties help sustain life on Earth

The uneven distribution of charge in water molecules allows them to bond to each other and to surfaces, enabling them to move against gravity, including up plants through roots and stems. These bonds also keep water in a liquid state over a wider temperature range and make it less dense as it freezes. This causes ice to float and form an insulating layer for underwater ecosystems, from which all life originated.

Technologies developed for the ISS have brought benefits to people on Earth

About 93% of water used onboard the International Space Station is recycled through filtration and purification systems that have since been used in regions lacking access to clean water. Treatments to mitigate bone loss and muscle atrophy in astronauts can also help aging adults.

Local governments are responsible for more than 148,000 public water systems across the US

From large municipal utilities to small rural systems, local governments are tasked with providing clean water to almost every American community. The US operates over 148,000 public water systems.

Strict rules dictate the making of Champagne

Some regulations, such as geographical area and grape varieties, are fairly well known. But to be true Champagne, winemakers must follow guidelines for all sorts of finicky things, including pruning, press yield (how much juice is extracted from the grapes), alcohol content, vineyard management, and aging, among others.

Desalination involves costly, energy-intensive methods for producing freshwater

Thermal desalination heats saltwater to produce steam, and reverse osmosis forces saltwater through a membrane that only allows water through. In both cases, freshwater is collected and remineralized for consumption, while wastewater brine is often returned to the ocean, where it may harm marine organisms.

Earth's easily accessible surface water in rivers and lakes accounts for about 0.01% of all the water on Earth, but 70% of this surface water is used for agriculture.

How disgorgement works while making sparkling wine

After riddling, winemakers still need to dispose of collected sediment in wines. While this was once done by hand, the modern method of freezing the bottle's neck and removing the now-solid sediment is ubiquitous. In this short video, an enologist (wine expert) from California’s Halter Ranch vineyards explains each step of the mechanical disgorgement process, complete with footage from their production line.

The federal government allowed toxic chemicals into alcohol during Prohibition

Industrial alcohol was still legal during Prohibition, and was often used by bootleggers. In an attempt to disrupt the black market, the government required toxic additives to be included in industrial alcohol, leading to more than one death.

Most of the 86,000 consumer chemicals registered with the US EPA have never received rigorous toxicity testing, though not all those are still in current use.

Learn how aquifers and wells provide the largest reserves of accessible freshwater on Earth

Roughly a third of Earth's freshwater is stored underground in aquifers—permeable and porous rock formations where water naturally flows from the Earth's surface and accumulates. About half of this groundwater is accessed through wells, a feat of engineering used for thousands of years.

Watch underwater photosynthesis make water look like champagne

In shallow waters where sunlight can reach, photosynthetic reactions absorb water and dissolved carbon dioxide, producing bubbles of oxygen at the surface of plants. As these bubbles rise to the water's surface, a fizzy appearance is created.

Watch students comically portray how plants can detoxify the environment

Through a series of processes that collectively make up phytoremediation, plants can take up pollutants from soil and water through their roots, then break them down, release them as less harmful gases, or store them within their cells. Any plants that sequester heavy metals or other toxins must be removed and managed after the environment is decontaminated.

See this interactive global map that highlights which forever chemicals have been detected in specific wildlife species, providing data on hundreds of species exposed to these hard-to-breakdown substances.

Watch experts blindly taste test Champagne and other sparkling wines

Champagne’s prestige typically comes with a high price. So is it worth it? Professional wine judge Dr. Matthew Horkey invites a Champagne expert and a producer to a blind taste test to find out. The individuals try sparkling wines from across the world and do their best to sniff out (sip out?) which is the real-deal Champagne.

Pollution from lead battery recycling has led to widespread contamination

Many small-scale operations worldwide remain unregulated, bypassing environmental regulations and causing increasing health threats, primarily to children. A 2020 report by UNICEF found that one-third of the world's children are being poisoned by lead from recycled batteries, among other sources.

Supplements often have issues with impurities, toxins, and inaccurate labels

Consumer Reports' tests of more than 20 supplement powders and shakes in 2025 found that more than two-thirds of them contain unsafe levels of lead. Some contained 10 times the amount of lead that's considered acceptable to ingest in a day. The levels they found, in some cases, were even higher than when they tested the products 15 years earlier.

What's the difference between an ale and a lager?

The major distinction is that ales are typically fruitier, while lagers are cleaner and crisper. This video breaks down several more of the nuanced differences between the two styles.

During manufacturing, lithium-ion and alkaline batteries are tested for short-circuiting

Lithium-ion batteries are made by manufacturing anodes, cathodes, and electrolytes via chemical processes, assembling these components into cells, and enclosing multiple interconnected cells within a protective casing. Disposable alkaline battery production involves filling steel containers with preforms—rings of powdered cathode material—paper-based separators, electrolyte solution, and an anode gel.

We can get food poisoning from spending time in swimming pools, lakes, rivers, and ponds

Some of the same pathogens that may sicken us in food or water may also sicken us in recreational swimming environments. Bacteria can rub off of people’s (or animal’s) bodies or contaminate the water through a diarrheal episode. Washing your hands for at least 20 seconds before eating food if you are at the beach, pool, or other similar environments and being sure not to swallow the water are ways to help keep safe.

Comparing bioremediation with other treatment techniques, at three levels of complexity

Physical manipulation, such as collecting and moving contaminated material to a landfill, or chemical applications, which use strong, expensive substances and produce harmful byproducts, can be costly. While bioremediation leverages naturally occurring degradation processes that can be augmented without disrupting impacted ecosystems, these processes may be less effective in environments that bioremediation organisms are not adapted to.

How water pressure affects the body

The extreme conditions of the deep sea include increasing amounts of pressure as explorers and organisms descend into its depths. The major danger for both fish and humans is the way pressure changes how body tissues absorb chemical molecules...

Understanding how the commodification of water has contributed to global water scarcity

In 2010, the UN General Assembly recognized access to water and sanitation as a basic human right, noting that an estimated 884 million people worldwide lack access to safe drinking water. The treatment of water as a commodity and reserves as property has contributed to unequal access and competition over its use, which is expected to intensify due to climate change.

Farming accounts for about 75% of the 1.9 trillion gallons of water drawn from the Colorado River each year, with about half used to irrigate crops fed to livestock.

Explore how close you live to some of the most contaminated places in the US

Known as Superfund sites, these toxic locations undergo long-term cleanup to remove hazardous waste, protect health, and restore land for safe reuse. As of 2025, the EPA lists around 1,300 active Superfund sites on its National Priorities List, with more than 450 cleaned and removed since 1980.

The industrial methods for recovering helium, including filters and cryogenic separation

Membranes with microscopic pores of varying sizes can be used to selectively filter out components of natural gas, including helium, which can then be concentrated. Because helium requires the lowest temperature of all elements to condense into a liquid, extracted natural gas can also be cooled until only helium remains as a gas.

Environmental DNA monitoring can help detect the presence of invasive species

Genetic material that organisms deposit into water, soil, or air can be identified by analyzing samples from each environment, allowing land managers to more reliably detect and track organisms than visual surveys alone. eDNA has been used to develop early warning surveillance systems for various invasive marine species.

The risks of bioremediation, from intermediate products to ecological disruption

A step in the series of complex biochemical reactions involved in the implemented bioremediation process may produce dangerous molecules—sometimes more toxic than the initial pollutants—that require ongoing monitoring to ensure optimal conditions for processing these intermediates toward the eventual, safe outputs. Introducing non-native nutrients or species, including GMOs, may alter existing food webs and gene pools.

Watch 'Last Week Tonight' explore the risks of 'forever chemicals,' a group of human-made chemicals used in everyday products to make them resistant to water, stains, grease, and heat. (Warning: language.)

A standard glass of champagne poured straight down releases about a million tiny carbon dioxide bubbles, according to two decades of research by a French physicist.

Why Water Towers Are Built This Way

Watch how metals are extracted from rechargeable devices during recycling

Recyclable batteries found in cars, phones, power tools, and other electronics contain lithium, cobalt, nickel, and other precious metals, whose reuse generates 70% fewer emissions than during their initial mining. Upon shredding these devices, a filter press squeezes the pieces through a proprietary fluid, which separates them for future reuse.

Although vinegar was first discovered when wine was left to sour after exposure to air, the fermentation of different base ingredients contributes to the variety of vinegars seen today.

Extreme heat puts people at risk of developing kidney stones

It's essential to remain hydrated in summer weather to keep your body healthy, but one reason is to help dilute minerals that naturally build up if they aren't excreted in our water-fueled urine. Doctors recommend people generally drink 64 ounces of water a day and also eat foods with salt to help ward off dehydration.