When is a domestic water supply considered to be of good quality?

A domestic water supply is considered to be of good quality when it is free from disease-causing organisms. This means that the water must be safe for consumption and use, free from pathogens that can lead to illness or disease. The presence of harmful microorganisms in water can pose significant health risks, especially to vulnerable populations such as children, the elderly, and individuals with weakened immune systems. Ensuring that water is free from such organisms is fundamental in public health and safety standards, making it a critical factor in determining water quality.

Other aspects of water quality, such as pH levels, temperature, and mineral content, can influence taste, corrosion potential, or other physical characteristics but do not singularly determine its safety for health-related purposes. For instance, low pH can lead to corrosive water, high temperatures can promote bacterial growth, and high mineral content might affect palatability but does not necessarily indicate safety. Thus, the paramount characteristic of good-quality domestic water is its cleanliness, particularly in terms of biological safety.