Temperature is important to a water system, as cool water can hold more oxygen than warm water. Changes in temperature over a stretch of stream may show a source of pollution to the water such as a drain from a parking lot or factory.

Water temperature is important for fish spawning and aquatic life. Between May and September, when trout are spawning, water should be less than 12°C. Between October and April, water should be less than 20°C for general trout health and less than 25°C for most native fish. Water temperature is affected by climate and by discharges of cooling water from industry. Temperatures are naturally higher in the northern Waikato than in streams near Taupo.

Water temperature has an important effect on the chemical, physical, and biological processes occurring in aquatic environments. Sudden fluctuations or high temperatures can stress or kill fish.

A site on a stream or drainage ditch where water temperature records are made.

The temperature of surface waters varies according to the season. Groundwater has a much smaller variation in temperature range. 25°C

The temperature of the water delivered by Tucson Water can vary depending on the time of year and the location where the measurement is taken. Part of the reason for this variability is that our water supply comes from more than 200 different wells, and groundwater temperature is a function of depth below the surface and the geology surrounding the well. The temperature of the water can also change as it flows through our drinking water system, depending on outside temperatures. The water at your tap can be 85 degrees or higher and can be affected by your private plumbing. Water temperature can affect the taste of your drinking water. Storing tap water in a clean container at room temperature or in the refrigerator will give a more refreshing taste.