GPM stands for “gallons per minute,” and it's the measure of how much water flows through a shower head in a minute of operation. Because showers account for a full 17% of all residential water use, in 1992, the US federal government passed rules requiring all shower heads be restricted to allow no more than 2.5 gallons per minute of water flow.
For a 10-minute shower, that's still an impressive 25 gallons of water, and it adds up to over 9,000 gallons of water a year. In 2016, New York City and Colorado passed tighter legislation, restricting shower heads to a maximum of 2.0 gallons per minute of water. In 2018, California implemented a 1.8 GPM maximum. There are also low-flow and eco-friendly shower heads with an even lower water flow, of 1.75 GPM or even 1.5 GPM.
Shower heads are manufactured in a variety of sizes and have similar or different configurations and shapes. Newly designed shower heads have multiple spray settings and include a hybrid setup. A hybrid setup includes a handheld shower head with an adjustable hose which can be used freely attached to a fixed shower head. Each shower head features its own specific functions fitted for different uses. Most shower heads have three major spray settings which are aerating spray, stream spray and atomizing spray each setting adheres to gallons per minute (GPM) shower head flow rates and customer preferences.
According to the EPA, consumer market research shows that three key factors influence customer satisfaction taking into consideration certain household conditions:
Flow rate across a range of pressures
Optimize Water Flow Rates
To ensure optimal water efficiency using your shower head, your system pressure should be between 20 and 80 pounds per square inch (PSI). The pounds per square inch in water pressure optimizes performance and your shower experience by delivering better water flow through the shower head. For best performance water should be routed through a shower valve. This will prevent changes in water pressure. A plumber can check the compatibility of the shower valve and shower head making sure the valve meets the standard flow rates of the shower head.
Periodic checking for scale buildup is important to keeping the optimal flow rate of your shower head. However, if your flow rate is still not optimal you can remove the flow restrictor as most shower heads come with a flow regulator pre-installed. Keep in mind this will lead to an increase in water use and a decrease in any net water savings. Replacing current inefficient shower heads with new ones designed to use 2.0 GPM or 2.5 GPM or if you reside in California 1.8 GPM will lead to a greater overall net savings over time. However, if installing and using multiple shower heads at the same time the volume of your water use increases substantially. WaterSence shower heads are certified by the EPA to use no more than 2.0 GPM.
The choice of material for your shower head matters. Solid brass shower heads are preferable to some because they are easy to clean, are long lasting and corrosion-resistant. If you are searching for a good polished brass shower head check out the Speakman High Pressure Shower Head. Other materials include metal, plastic and chrome.
What is a Flow Restrictor?
Because shower head regulations changed fairly quickly in the 1990s, from imposing a 3.5 max GPM in 1990, to a 2.5 max GPM in 1992, and some states have different or lower regulations, many manufacturers adapted to these new and variable requirements by installing flow restrictors. A flow restrictor is simply a small valve, placed inside the base of a shower head where it meets the water pipe, that reduces water flow from the pipe to the head.
By using these valves to restrict water flow, manufacturers didn't have to completely redesign shower heads in order to be sold in individual markets or to comply with changing regulations; they could simply install flow restrictors as necessary.
The problem with the flow restrictors that we saw in the 1990s and 2000s is precisely this; instead of redesigning shower heads to be more water efficient, delivering satisfying water pressure and a good shower experience with less water, manufacturers simply reduced the water flow into the shower head with a restrictor. This led to consumers complaining that their showers were just a trickle of water, and not sufficient to feel clean.
Consumers were unhappy with the restricted flow of water and felt that it just made their showers longer in duration, without actually any net water savings, and many people removed them from their shower heads.
2.0 GPM vs. 2.5 GPM Shower Head
If your shower head was made after 1992 and hasn't been replaced or upgraded to a low-flow model, chances are that you currently have a 2.5 GPM shower head.
Switching to a 2.0 GPM shower head could save you:
1,825 gallons of water a year
$25 per year in reduced energy costs
The savings go up the more people there are in a household. With a 2.0 GPM shower head, a family of four could save:
7,300 gallons of water per year
$100 a year in reduced energy costs
In fact, the EPA estimates that, if everyone in the US used a 2.0 GPM shower head, we could save:
260 billion gallons of water every year
$2.2 billion in water utility bills
$2.6 billion in energy costs for heating water
In other words, restricting water use during showering has a huge impact on our environment, both in terms of preserving fresh water supply, and in terms of reducing energy usage. It's the smart thing to do.
How to Choose A Low-flow Shower Head
Consumers are legitimately upset and dissatisfied with the quality of many low-flow shower heads. The water can trickle out of the shower head, making it difficult to get clean or to enjoy a shower. It can make every shower take more time, offsetting the value of reducing the water flow, and make showers unpleasant, where only a small part of your body is in the water at any one time.
However, many manufacturers today are solving the need to reduce water flow without simply resorting to flow restrictors. Many modern shower heads have been designed from the inside out to use less water while still producing a satisfying level of water pressure and spray from the shower head, using innovative design and technologies to improve your shower experience.
If you want the cost savings of a low-flow shower head, and to help reduce your environmental impact when you shower, here are a few things to look for:
Consider a high-performance eco-friendly shower head
Shower heads that are sold as eco-friendly or environmentally safe often have an even lower GPM than is regulated, with flows as low as 1.5 GPM. The reason to consider these models is that they have usually been designed ground up to deliver a satisfying shower with reduced water usage.
With a new, eco-friendly shower head with an even lower flow than required, you know that they aren't simply using a restrictor to reduce water flow to the maximum allowable amount but have instead redesigned the water flow entirely.
Choose an adjustable shower head
If you have a new, high-quality, adjustable shower head, you may find that there are times when you naturally want more or less water flow during your shower. Giving yourself the option to adjust the water flow on demand may help you naturally reduce water consumption without sacrificing any enjoyment.
Consider upgrading to a handheld shower head
Handheld shower heads are a great way to make showers both more efficient and more enjoyable. They can spray water down on you from above like a conventional shower head, but you can also use the shower head to spray water exactly where you want it, at any angle. This can make rinsing away soap and dirt more efficient, and help you feel cleaner after every shower.