The average temperature of drinking water varies by geographical location; in Milwaukee, the average temperature of cold tap water is 49.6 degrees Fahrenheit. The average temperature of drinking water can change depending on the time of year, the location where the water temperature is being measured and different environmental factors, including the presence of manufacturing plants and natural bodies of water.
Tap water from the northern states compared to the southern states can vary by as much as 6 to 10 degrees. The average temperature of water in northern states, such as Michigan or Vermont, is 45.1 degrees Fahrenheit. The average temperature of cold drinking water in southern states, such as Florida and Alabama, is 50 degrees Fahrenheit.
The temperature outside is the largest factor that plays into the temperature of cold tap water. Since it is only filtered through a plumbing system and is not sent through a hot water heater in the way that hot water is, it can vary depending on the temperature outside. If the actual faucet of the sink has been allowed to sit in the sun or has been exposed to heat, the temperature of the cold tap water will generally be affected, but will return to a more moderate temperature. Many older taps will have warmer cold tap water because they are more susceptible to heat.