Nutrition and Hydration: What is considered drinkable water?

October 8, 2025 •

5 min read

According to the World Health Organization, contaminated water is linked to the transmission of numerous diseases, posing a significant risk to public health. Understanding what is considered drinkable water? is a foundational aspect of proper nutrition and overall well-being, as it involves meeting stringent safety and quality standards.

Quick Summary

Water must meet specific health and quality standards to be considered potable and safe for human consumption. Factors determining drinkability include microbiological and chemical contamination, physical properties like clarity and odor, and the presence of dissolved solids.

Key Points

Definition of Potable Water: Drinkable water, or potable water, is safe for human consumption and free from harmful microbiological, chemical, and physical contaminants.
Importance of Hydration: Clean water is essential for optimal health, supporting vital functions like temperature regulation, joint lubrication, digestion, and waste removal.
Key Water Quality Parameters: The safety of water is assessed by physical (turbidity, color, odor), chemical (pH, metals, chemicals), and biological (bacteria, viruses) indicators.
Common Contaminants: Water can be contaminated by microorganisms from waste, inorganic chemicals like lead and arsenic, and organic chemicals from industrial or agricultural runoff.
Effective Purification Methods: Options like boiling, filtration, reverse osmosis, UV purification, and chlorination can make water safe, each with its own advantages and limitations.
Impact on Nutrition: Safe drinking water is a fundamental component of a healthy diet, helping to prevent dehydration and ensuring the body can properly utilize nutrients from food.

The Science Behind Drinkable Water

Water is not just a beverage; it is a vital nutrient for every cell, tissue, and organ in the human body. Proper hydration is a cornerstone of overall health, regulating body temperature, lubricating joints, and aiding in nutrient absorption and waste removal. However, the quality of that water is paramount. Just as a balanced diet requires nutrient-rich foods, effective hydration demands clean, uncontaminated water. For water to be considered drinkable, or potable, it must be free from biological, chemical, physical, and radiological contaminants that could pose a threat to human health. Standards are set and monitored by health authorities like the World Health Organization (WHO) and national agencies, ensuring that the water supply is safe from source to tap.

What Makes Water Potable?

For water to be declared safe for drinking, it must meet a complex set of criteria that assess its quality. These health-based standards are critical for preventing waterborne illnesses and ensuring the water is aesthetically acceptable—meaning it has no unpleasant color, taste, or odor. The WHO's Guidelines for Drinking-water Quality provide an internationally recognized framework, focusing on proactive risk management from the water source to the consumer. This involves continuous monitoring and control to prevent contamination at various stages of the water supply system.

Key Parameters of Water Quality

To ensure water is safe to drink, its quality is measured by several key parameters that fall into three main categories: physical, chemical, and biological.

Physical Parameters:
- Turbidity: This refers to the cloudiness or haziness of the water, caused by suspended solid materials like clay, silt, and microorganisms. High turbidity can protect pathogens from disinfectants.
- Color, Taste, and Odor: These organoleptic properties are important for ensuring water is pleasant to consume. Disagreeable attributes can be caused by natural organic matter, industrial discharges, or certain minerals.
- Temperature: Consistent, cool temperatures are desirable for drinking water. Temperature influences other factors, such as the water's chemical and biological activity.
- Total Dissolved Solids (TDS): This measures the combined content of inorganic and organic substances dissolved in the water, affecting taste and suitability.
Chemical Parameters:
- pH Level: Indicates the acidity or alkalinity of the water, with an optimal range between 6.5 and 8.5. Extreme pH levels can impact aquatic life and treatment processes.
- Heavy Metals: Toxic metals like lead, arsenic, and mercury can enter the water from natural deposits, industrial practices, and plumbing.
- Nitrates and Nitrites: These contaminants often come from agricultural fertilizers and human or animal waste. High levels can pose a risk, particularly to infants.
- Chlorine and Disinfection Byproducts: Chlorine is used to disinfect public water, but it can react with organic matter to form potentially harmful byproducts like trihalomethanes (THMs).
Biological Parameters:
- Microorganisms: The presence of bacteria (E. coli), viruses, or protozoa (like Giardia and Cryptosporidium) indicates fecal contamination and poses the greatest risk to health.

Common Contaminants and Their Sources

Contaminants can enter water sources from various environmental and human-made origins. Understanding these sources is the first step toward effective mitigation.

Microbial Contaminants:
- Bacteria and Viruses: Often come from human and animal waste, including sewage and septic systems.
- Parasites (Protozoa): Found in surface water contaminated by animal feces.
Inorganic Chemical Contaminants:
- Lead: Leaches from corroding plumbing, especially in older homes and municipal systems.
- Arsenic and Fluoride: Occur naturally in groundwater from mineral deposits. Excessive levels are known to cause significant health problems.
- Nitrate: Enters groundwater from agricultural fertilizer runoff and human or animal waste.
Organic Chemical Contaminants:
- Pesticides and Herbicides: Run off from agricultural fields and can cause health issues.
- Industrial Chemicals: Solvents, petroleum products, and other chemicals can contaminate water through improper disposal or spills.
- Pharmaceuticals and Personal Care Products (PCPs): These are considered “emerging contaminants” that enter water supplies through human waste.
Radiological Contaminants:
- Radioactive elements can enter water from the erosion of natural mineral deposits.

Comparison of Water Purification Methods

Various methods can make water safe to drink. The most effective approach depends on the source and type of contamination. Below is a comparison of common purification techniques:


Method	Primary Removal Focus	Pros	Cons
Boiling	Kills bacteria, viruses, parasites.	Highly effective against biological contaminants, simple, and inexpensive.	Doesn't remove heavy metals, nitrates, or other dissolved chemicals; alters taste; energy-intensive; leaves no residual protection.
Filtration	Removes suspended particles, some bacteria, and organic chemicals (taste/odor).	Relatively easy to use; improves aesthetics (taste and smell).	May not remove viruses, dissolved salts, or heavy metals; filters require regular replacement.
Reverse Osmosis	Effectively removes a very wide range of contaminants, including heavy metals, salts, nitrates, and microorganisms.	Produces very pure water; highly thorough.	Can remove beneficial minerals; high water waste; expensive and energy-intensive; requires regular filter/membrane replacement.
UV Purification	Inactivates bacteria, viruses, and protozoa.	Effective against most pathogens; no chemicals needed.	Ineffective against dissolved chemicals or particles; requires pre-filtration in turbid water; leaves no residual disinfectant.
Chlorination	Kills most bacteria and provides a residual disinfectant effect in the distribution system.	Inexpensive and widely used for public water supplies.	Limited effectiveness against certain protozoa (e.g., Cryptosporidium); can create harmful disinfection byproducts (THMs) by reacting with organic matter.

The Connection to Health and Diet

Water is an essential, zero-calorie nutrient that plays a crucial role in maximizing physical performance, aiding digestion, and maintaining proper bodily function. Proper hydration is particularly important for individuals managing weight, as drinking water can promote a feeling of fullness. Beyond physical benefits, clean water supports mental well-being, helping with focus and concentration. Ignoring hydration or consuming contaminated water can have severe consequences. Dehydration, even mild, can lead to fatigue, headaches, constipation, and cognitive impairment. Contaminated water, on the other hand, can cause life-threatening waterborne diseases and long-term health problems. Choosing safe, drinkable water is not a luxury but a fundamental part of maintaining a healthy body and mind within the broader scope of proper nutrition. It ensures your body functions optimally, allowing it to efficiently use the nutrients from your diet and prevent unnecessary health risks.

Conclusion

To answer the question what is considered drinkable water?, it is water that is not only clear and odorless but has also been tested and verified to be free of harmful contaminants to internationally recognized standards. While many factors can affect water quality, a range of reliable purification and treatment methods are available to ensure safety. For individuals, this may mean investing in a quality home filtration system or simply boiling water when necessary. For communities, it requires strong governance and investment in reliable water supply systems. Prioritizing safe drinking water is a non-negotiable part of a healthy lifestyle and proper nutrition. It is a critical step towards preventing disease and promoting overall well-being. For more information on drinking water safety, consult resources like the WHO's Guidelines for Drinking-water Quality (GDWQ).

Frequently Asked Questions

The key difference is the treatment process. All public tap water is treated to meet minimum safety standards set by governing bodies like the EPA. Purified water, whether bottled or from a home system, undergoes additional rigorous processes like reverse osmosis, ozonation, or distillation to remove a wider range of contaminants.

While clear, odorless water is a good sign, many dangerous contaminants are invisible. The most reliable way is to check your local water quality report, often provided by your municipal water company. If you have concerns, consider having your water tested by a certified lab, especially if you have a private well.

Not necessarily. In the U.S., tap water is regulated by the EPA, while bottled water is regulated by the FDA. Both are generally safe. Some bottled water is simply tap water that has undergone additional purification, while others come from spring or mineral sources. For most people, tap water is the more cost-effective and environmentally friendly option.

Consuming contaminated water can cause short-term and long-term health issues. Acute effects include gastrointestinal illnesses from microbial pathogens like E. coli or Giardia. Chronic effects from long-term exposure to chemicals like arsenic or lead can include organ damage, reproductive problems, and cancer.

No. Boiling is highly effective at killing biological contaminants like bacteria, viruses, and parasites. However, it does not remove chemical pollutants such as lead, nitrates, or pesticides, and it can even increase their concentration as some water evaporates.

The best filter depends on your water source and the contaminants you want to remove. Carbon filters improve taste and remove some chemicals. Reverse osmosis is highly effective for a wide range of contaminants, including heavy metals and salts. UV filters target biological contaminants. Many systems combine these technologies for comprehensive purification.

Water is a transport medium for nutrients. It helps dissolve vitamins, minerals, and other nutrients from food, carrying them into the bloodstream and to the cells that need them. Dehydration can impair this process, making it difficult for your body to absorb essential nutrients effectively.