Water flow rate is generally an important consideration when shopping for the best tankless water heater. The flow rate is a term that should be understood if you plan to shop for such a water heater. It is a term used to describe different things.

What is the age of your faucet?

According to the Federal Energy Policy Act of 1992, it is important that all shower fixtures and faucets made in the United States should have a flow rate of not more than 2.2 GPM at 60 PSI. However, if you have older fixtures in your property, you will have a much higher flow rate.

Things to know:

Here are certain terminologies and things you should be aware of:

  • Flow from the tap: This terminology refers to the number of gallons of water you get in a minute. To determine this rate, you will find fancy devices on the market. Otherwise, you can just open the tap and place a bucket under the tap. Just take a timer to identify how long it takes to fill the bucket. Of course, you should know the capacity of the buckets as well when you do this.
  • Tankless heater flow rate: When you take the case of a tankless hot water heater, the term flow rate is something different. Apart from the flow rate in the method mentioned above, you will have to add the temperature rise needed for meeting the required water temperature. Just consider the temperature of your groundwater and the temperature you wish to achieve. By doing so, you can determine the rise. Once this number is obtained, you can easily identify the flow rate. The number denotes the number of gallons can increase in temperature for meeting your tap requirement per minute.


In the case of tankless water heaters, the flow rate refers to the gallons of water that the heater can handle in a minute.