Water is an essential resource for all forms of life on earth. It is crucial for vital physiological functions, hygiene, food production, and industrial applications. The quality of water is a significant concern for humanity's health and survival. The term 'Water Quality' refers to the physical, chemical, and biological properties of water that its suitability for specific uses, mostly for human consumption. 

1. Physical Factors impacting Water Quality

Temperature: The temperature of water affects its quality significantly. Higher temperatures speed up chemical reactions, encourage the growth of microorganisms, and reduce oxygen levels in the water. While some aquatic organisms thrive in warm water, others require cooler temperatures. Therefore, any drastic changes in water temperature can disrupt the aquatic ecosystem and affect water quality.

Turbidity: Turbidity is a measure of the cloudiness or haziness of the water caused by suspended particles. High turbidity levels can block sunlight, affecting photosynthesis in aquatic plants, and can also carry harmful pathogens and pollutants. Therefore, turbidity is a significant indicator of water quality.

c. Color and Odor: The color and odor of water can reveal a lot about its quality. Clear, odorless water is generally considered healthy. However, changes in color and smell could indicate contamination.

2. Chemical Factors affecting Water Quality

PH Level: The pH level of water measures its acidity or alkalinity. A pH level of 7 is neutral, below 7 is acidic, and above 7 is alkaline. The ideal pH for drinking water is slightly alkaline, around 7.2-7.8. Deviations from this range, either way, can make water unfit for consumption and can also harm aquatic life.

Dissolved Oxygen: Dissolved oxygen in water supports the survival of fish and other aquatic organisms. Low levels of dissolved oxygen, resulting from pollution or eutrophication, can lead to the death of aquatic life, significantly affecting water quality.

Nutrients: While nutrients like nitrogen and phosphorus are essential for aquatic life, excessive amounts can cause harmful algal blooms and eutrophication, leading to water quality degradation.

3. Biological Factors impacting Water Quality

Pathogens: Pathogens are disease-causing microorganisms, including bacteria, viruses, and parasites, found in water. They are a major concern for water quality as they can cause several waterborne diseases.

Algae: Algae are a natural part of the aquatic ecosystem. However, when nutrient levels in water are high, it can lead to excessive growth of algae, also known as algal blooms. These blooms can produce toxins harmful to humans and wildlife, affecting water quality.

Invasive Species: Invasive species can significantly impact water quality by disrupting the existing ecosystem. They can outcompete native species for resources, leading to a decrease in biodiversity.

4. Human Factors influencing Water Quality

Industrial Pollution: Industries often discharge untreated or inadequately treated wastes into water bodies, leading to severe contamination. These wastes can contain a range of harmful substances, including heavy metals, chemicals, and radioactive materials, which drastically affect water quality.

Agricultural Runoff: The use of fertilizers and pesticides in agriculture can contaminate nearby water bodies when washed away by rain. These substances can degrade water quality and harm aquatic life.

Municipal Wastes: Improper disposal of municipal wastes, including sewage, can lead to the contamination of water sources. Pathogens and toxic substances present in these wastes can pose serious threats to water quality.

Overexploitation: Overexploitation of water resources can also affect water quality. Overpumping of groundwater can lead to saltwater intrusion in coastal areas, making the water unfit for consumption.

The quality of our water resources is under constant threat due to various natural and anthropogenic factors. Understanding these factors is crucial in devising effective strategies for water management and conservation. While some factors are beyond human control, others, especially those related to human activities, can be managed to a large extent. Ensuring good water quality is not just crucial for our health and well-being, but it is also essential for maintaining biodiversity and the overall health of our planet.