The threshold odor number (TON) limit for odor is?

The threshold odor number (TON) is a measure used to quantify the concentration of odorants in water, specifically measuring the dilution at which a trained panel can detect an odor. A threshold odor number of 3 TON is considered a standard limit for acceptable odor levels in drinking water. At this level, odors become noticeable to most people, indicating that the water might begin to have an unpleasant smell.

Adhering to this limit is essential in ensuring that drinking water remains palatable and does not repulse consumers, which can affect public perceptions of water quality. Therefore, maintaining water quality at or below this threshold is crucial for public health and safety, as well as consumer satisfaction.

Establishing a higher limit, such as 5 TON or 10 TON, could lead to water that has a noticeable odor, which may be perceived as undesirable or unacceptable, potentially leading to decreased utility of the water system.