How many GPM do you need for a shower?

Before to know the answer to this question: How many GPM do you need for a shower? You need to know what GPM is and why it is important for your daily shower.

Let’s start with what is GPM:

The basic meaning of GPM is Gallons per minute. It is also known as rate of water flow or Flow rate whatever you say. In the context of the hot water heater; GPM is a measurement of how many gallons of water flow out each minute of your shower. Say for example: in 1992, the maximum 2.5 GPM is the “federally mandated flow rate” need for brand new shower heads. That means 2.5 gallons of hot water flow out every minute not more than that. At the same time, the most valuable thing is that over the time; the GPM flow rates decrease at a notable figure. If your today modern shower head made in the earlier time like 19080 or 1990s era, its flow rate could not be less than 3.5 GPM.

Now we are going to talk about why GPM or flow rate is important:

For the future water and energy saving factor the federal, local government or federal regulators regulate flow rates of shower head. That’s why they always calculate:-

Calculation: A Standard VS Low Flow Shower Head Benefits

A standard 2.5 GPM shower head uses means 2.5 gallons of water each minute. That’s actually 25 gallons of water in TEN MINUTE shower.


A lower flow 2.5 GPM Shower head uses means 2.0 gallons of hot water each minute. That’s actually only 20 gallons of water for TEN MINUTES Shower.

Resulting, if everyone from United States decided to install 2.0 GPM shower heads then the EPA estimates annual savings stands for:

  • 260 billion gallons of water saves in a year.
  • It saves 2.2 billion dollar utility bills of water.
  • It also saves 2.6 billion dollar energy cost for water heating.

Oh My God dear, it’s a lot of billions saves in a year. But why the government needs to take initiative and impose regulation to water use in the shower. Because for some people showers is a utilitarian invention. Actually, they think that it is the easiest way to remove the dirt of whole day without the hassle of filling of a bathtub. For some others, the showers wash far off moreover than mud and it can help to feel happy. Basically, they take it as private spacing where they can escape the reality and wash away from the day’s annoyances. In that case, most of them tool long time shower. Resulting, wastage ratio of water flow heats the many policies and this is one of the most common factors in raising the utility bills of your home. At the end result these tankless are energy saving unit to protect your energy bills.

In that part, let’s talk about how many GPM do you need for a shower?

Basically, the US well-known organization Home water works said, after clothes washer and toilet showers are the 3rd largest using a factor of water. The average number of American uses 17.2 gallons of water during a shower with the average time length of 8.2 minutes. In that case, you need to select the tankless water heater unit with the minimum hot water serving capability of 2.1 gallons per minute.

At the same time, if we discuss with add up whole family needs of hot water then it’s can be briefly like: most of the American take one shower in a day. In that way if we figure out the potential energy consumption for showering 6 times in a week. Then it’s look like 17gallons of hot water an average 8 minutes shower X 6 showers in a week is equal to 102 gallons of hot water use by a person in a week. Now if you multiply this amount with 52 weeks you have got the total hot water use by a person in a year and it is approximately 5304 gallons. If this amount of hot water uses by four member family the amount is approximate 21216 gallons per year. This calculation assumes 8 minutes for every shower. So, you have to buy a hot water heater unit with the capacity to deliver 2.1 or more gallons of hot water per minute.


At the end, we hope that by following this calculation and article you can easily find out your best tankless water heater unit which is suitable for you to fulfill you and your family hot water demand.

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