The availability of clean water is essential to the survival of human beings and other animals2. We use water daily for various activities, like cooking, drinking, washing, and agriculture. We access it typically from freshwater lakes, underground aquifers, rivers, streams, and other natural resources. How can we check if these sources have the cleanest water in the world?
Using contaminated water for these activities causes health problems for us. For this reason, we need constant access to clean tap water, setting standards to maintain high water quality.
This article will explore a clean water source's physical, chemical, and biological qualities. We will also discuss ten countries with the cleanest drinking water.
Water quality refers to water's physical, chemical, and biological properties. Examining water quality helps determine which water is safe for drinking4. Lack of water quality tests could lead to contamination, and contaminated drinking water is bad for human health. Here are the three water quality properties:
The physical quality of water refers to the total solid contents in water. The solid contents contain floating matter, settleable matter, and colloidal matter. Physical properties are the following:
Color in water can occur from decaying vegetation and humic matter leaching from peatland. It can also occur from natural salts of iron and manganese. Water can appear colored because of suspended materials. To determine the true colors of water, filtration is necessary.
Water color has to be removed before we can use water for human activities, especially drinking water. It is not pleasant aesthetically, and it reduces the efficiency of water disinfection by UV radiation, chlorination, and ozonation. The drinking water directive states that water color should be acceptable to consumers and have no abnormal change.
Clean water, either bottled water or tap water, should be colorless. So avoid water with sediments and color when you drink tap water or purchase bottled water.
Water taste and odor can be from foreign materials like organic compounds, dissolved gases, and inorganic salts. Taste and odor in water are often associated with microscopic organisms, decaying weeds and algae, and waste. The waste contains phenols, halogens, ammonia, and hydrocarbons.
High concentrations of iron, manganese, and other metals can give drinking water a high and unpleasant metallic taste. The Dilution number represents the intensity of taste and odor in water. The dilution number refers to the state where the water samples are mixed with odor and taste-free water until it is undetectable.
Unpleasant taste and odor in water are removable through aeration, ozonation, or adsorption. If water chlorination is the source of the taste and smell, it is removable by controlling the disinfection process.
Water temperature is one of the physical properties of water quality. The water temperature of clean water is usually cool. Its temperature only fluctuates over a few degrees, depending on the weather. Groundwater, natural springs, and other water bodies are typically cool. When the above water sources become drinking water, they maintain their cool temperature.
Turbidity refers to the suspended solid matter in water. The suspended matter could be clay, silt, organic matter, plankton, etc. Turbidity in water can occur because of soil erosion and the growth of microorganisms. To get high-quality water, the suspended matter needs filtration. However, high turbidity in water makes filtration expensive.
Water contains various chemical compounds that have cumulative effects on human health with extended exposure. These chemicals include arsenic, chloride, fluoride, zinc, iron, and manganese. However, if the water contains harmful chemicals, our health and immune system will be jeopardized.
Here are four major chemical properties of water that help determine water quality:
pH measures the acidity and alkalinity of water. It is the negative log of hydrogen ion concentration in water. The pH scale ranges from 0 to 14, with 0 representing high levels of acidity and 14 representing high alkaline levels. Freshwater lakes have acid levels between 4.5 and 5, while peatland's acid level is over ten because of the intense photosynthetic activities of algae.
Low pH values make chlorination very easy and effective, but pH values between 0 and 4 are dangerous for marine organisms. The pH value of safe drinking water5 is between 6.5 and 8.5.
Water alkalinity is the measure of water's capacity to neutralize acids. You can also refer to it as carbonates and hydroxides in water. It helps marine animals survive rapid pH changes in water. It also protects them from acid rain and acid from plastic waste: rocks, soils, salts, specific plant activities, and industrial wastewater influence alkalinity.
This measures the amount of salts in water. The salts in different water bodies vary. The salt in seawater is from sodium chloride (NaCl), while other saline waters get their salts from various types of dissolved ions. These dissolved ions are sodium, chloride, carbonate, and sulfate.
Water supply with high salinity is unsuitable for drinking. It reduces water quality, making it unsuitable for agricultural activities, industrial use, and household chores. So, avoid tap water that has a high salt content. It's not safe drinking water.
Calcium and magnesium are natural materials responsible for water hardness. It is a natural feature of water that improves its taste for consumption. There are two forms of water hardness: carbonate hardness and non-carbonate hardness.
They measure water hardness from soft (0 - 100 mg/l as CaCo3) to extremely hard (500 mg/l - 1000 mg/l as CaCo3). To remove hardness from tap water, boil it. You can turn it into drinking water once it cools down.
The biological properties of water refer to the microbial organisms in the water. These organisms are mostly disease-carrying pathogens. They are bacteria, fungi, algae, protozoa, helminths, and viruses. These pathogens often enter surface water through animal and human feces.
These pathogens reduce water quality and put human health at risk. The consumption of contaminated water leads to water-borne diseases.
Icelandic water has a high and consistent quality3. Freshwater lakes, rivers, and glaciers cover 6% of Iceland. However, Icelanders get most of their water from underground sources, i.e., underground aquifers. Icelandic water is one of the cleanest water in the world because it meets up with 99.44% of the Icelandic Drinking Water Regulation (IDWR).
Icelanders can freely drink water from any source because there aren't any expected health risks. 95% of Iceland's tap water is free from nitrates, calcium, and chlorine from natural spring water. You can drink the country's tap water if you're vacating there.
They have a high tap water quality that's safe for drinking. However, avoid drinking from streams and rivers near sheep farms because of agricultural contamination.
Finland is one of the top countries with the cleanest water in the world6. The country has 647 rivers and 168,000 lakes, and the government fiercely protects them. 85% of these water supplies received excellent environmental evaluations.
The majority of the country's water is from Lake Päijänte. The government has water purification plants that remove impurities from the water. The plants use water filtration and treatment methods like precipitation, sedimentation, UV treatment, activated carbon filtration, and chlorine disinfection.
Finland's tap water quality is better than bottled water, meaning drinking tap water is safer. The country has the cleanest water because strict waste management policies promote proper wastewater treatment.
Switzerland has high-quality drinking water. The tap water is cleaner than bottled mineral water. The country's water is from 1,500 lakes, 890 square kilometers of glaciers, multiple rivers, and streams.
More than a third of extracted groundwater is safe to drink without water treatment. 40% of Switzerland’s water is from natural springs and wells. They get another 40% from underground water sources and 20% from lake water.
However, water from some parts of Switzerland requires water treatment before it becomes drinkable tap water. A third of their water requires a single-stage treatment, while another third requires multiple stages of treatment.
Swiss treatment plants use membrane technology, ozonation, and active carbon to produce municipal drinking water for water treatments. They also perform water softening and decalcification in complex facilities to provide clean drinking water.
The Netherlands has an efficient water supply system that provides clean drinking water for its citizens1. The country's tap water system is better than that of the United States and Great Britain. They have high-quality drinking water without using chlorine for purification.
The lack of chlorine in the purification system prevents the corrosion of pipework and the formation of harmful compounds. It also gives water a better taste. The Netherlands changed the water pipelines in 1990. This aids in providing the best drinking water quality because the pipes are not too old and corroded.
The Netherlands' government has strict regulations to protect natural water sources to ensure that water plants only use a little filtration process for purification. Most of the country's water is from surface water, including the ones going in natural dunes.
Sweden is also a country with high-quality drinking water. They are part of the countries with the cleanest tap water in the world7. 50% of Sweden's clean drinking water comes from surface water (95,700 lakes). The other half of their drinking water is from groundwater. Residents of the country rarely drink bottled water. They mostly drink directly from the tap.
Sweden’s government has strict guidelines and constant monitoring to ensure adequate tap water quality. The Swedish purify their water in two stages. The first stage is decontamination with mechanical and mild chemical methods, while the second stage is organic pollutant extraction using slow sand filters.
Germany's water is among the best in the world because stringent quality control forbids the use of chemicals in the water filtration process. The absence of chemicals in the water gives their tap water a better taste. It doesn't taste like chlorine.
The German government's water protection policies provide enough water supply and guarantee the long-term availability of water. Also, they have clean water because the country has adequate clean air that helps keep contamination from causing water pollution.
Norway's water supply has low levels of heavy metals, pesticides, and other pollutants. This makes it one of the cleanest tap water in the world. Norwegian people get their water from multiple lakes, rivers, streams, and brooks.
The Norwegian government fixed 3,800 leaking drinking water pipes in 2016. This prevented the occurrence of gastrointestinal problems among its citizens.
Greenland has an abundance of clean water, especially in Nuuk. They provide clean water from glaciers and lakes. The government set strict guidelines that protect and regulate the water quality in Nuuk. They also test the water regularly to monitor changes and possible contamination.
Nuuk's water utility company also performs daily checks and maintenance of the water supply network. However, visitors not used to the taste of Nuuk's water might drink bottled water. Drinking Nuuk's tap water is safe because it is very soft. It has low levels of calcium and magnesium. You can use a water filter or boil it to make the tap water taste better.
There are two primary water sources in Malta. They are the underground water reservoirs and seawater. Malta has the fourth cleanest water for bathing in the world. They also have clean tap water that's safe to drink.
To make seawater drinkable, they use desalination and reverse osmosis. The taste of the tap water might be a little salty. There are three desalination and reverse osmosis plants in Malta. They're in Cirkewwa, Pembroke, and Ghar Lapsi.
Renowned for its pristine water quality, New Zealand primarily sources its water from protective catchment areas, including rivers, reservoirs, and underground aquifers. These regions, especially Wellington and Auckland, are subject to the rigorous Drinking Water Standards of the country.
Water in Wellington predominantly comes from the Hutt River, Wainuiomata, and Orongorongo catchments. Meanwhile, Auckland obtains its supply from dams in the Hunua and Waitakere ranges. Despite variations in taste due to different mineral content, tap water in New Zealand is generally safe to drink. Adjustments can be made for taste by boiling the water or using water filters.
Clean water has a clear color, and it is almost tasteless. A water source could have an odor because of the decaying weeds, algae, and waste. Clean tap water should have low acidity and hardness. Also, it should be free from salts.
Countries like Malta remove salt from their seawater to make it safe to drink, while others don't use chlorine to treat their water. Providing clean tap water reduces the demand for bottled water, thus reducing plastic waste in the environment.
Dinka, M. O. (2018). Safe Drinking Water: Concepts, Benefits, Principles and Standards. InTech eBooks.
Gunnarsdóttir, M. J., Gardarsson, S. M., St Jonsson, G., & Bartram, J. (2016). Chemical Quality and Regulatory Compliance of Drinking Water in Iceland. International Journal of Hygiene and Environmental Health.
Aucor. (2020). Finland’s water expertise is world class - Finland Toolbox. Finland Toolbox.
O’Connell , M. (2017). Water Quality in Sweden. The Borgen Project.
Jen’s a passionate environmentalist and sustainability expert. With a science degree from Babcock University Jen loves applying her research skills to craft editorial that connects with our global changemaker and readership audiences centered around topics including zero waste, sustainability, climate change, and biodiversity.
Elsewhere Jen’s interests include the role that future technology and data have in helping us solve some of the planet’s biggest challenges.