A tankless water heater that is rated with a flow rate of 8 GPM (gallons per minute) is capable of running these items at the same time in regions with an average groundwater This example is based on a tankless water heater that has a flow rate rated for 8 GPM.īased on the corresponding flow rates for each appliance that are listed. In the example below, you can see the impact that temperature has on flow rates. How Flow Rates are Affected by Temperature For example, if the starting water temperature is 52☏ and you need to raise the water temperature to 110☏. Then your tankless water heater must be able to raise the temperature of the water by 58☏ while still providing adequate flow to support the fixtures you wish to run at the same time. This causes the tankless water heater to work harder to increase the water temperature in colder climates, which in turn causes the flow rate to decrease in parallel. The reason for this is because in colder climates the groundwater starting temperature is colder than in warmer climates. If you would like more information on the hard water levels in your area please see our hard water map.Īnother important reason to know your average groundwater temperatures is if you are trying to determine which tankless water heater to purchase. Groundwater is so hard in some areas that water utilities must blend it with surface water to reduce the hardness.

If your water source is deep in the earth (higher pressure also contributes to increased calcium solubility) and the groundwater is very cold, you can almost certainly expect hard water.

Calcium has the opposite effect: the hotter the water, the less calcium it can dissolve. It is common knowledge that you can dissolve more sugar in hot water than cold. Most substances that dissolve in water, such as sugar, do not behave in this manner. Temperature is important to consider when dealing with hard water because calcium dissolves more easily in cold water.

Average Groundwater Temperatures for the Cities in Florida

Underground temperature map