Water usage is a concern for many people, for environmental or economic reasons. Since 1994, manufacturers have been required by federal law to limit their showerhead water flow to 2.5 gallons of water per minute (though some skirted the law for years by producing multihead models that collectively put out much more water). There’s also a federal guideline that showerheads can qualify for if they use 2.0 gpm or less. (In California, WaterSense is a state law.) For this guide, we looked at both 2.5 and 2.0 gpm models.
Or as the itself declares to all consumers and manufacturers: "Federal regulations mandate that new showerhead flow rates can't exceed more than 2.5 gallons per minute (gpm) at a water pressure of 80 pounds per square inch (psi)."
Shower head Flow Restrictor
Flow rate 6, 8, 9 lit/min
Suitable for all types of shower lever mixers
Screw between the shower lever mixer and shower hose
A customer pre-sets flow rate during the installation
Water and energy savings up to 50%
Guarantee: 5 years
On the other hand, this shower also brings a lot of downsides. If you are about enjoying warm water with this shower, you will increase the energy which is claimed bigger than the standard one. This is because the small droplets will cool easily. Besides that, shower with low-flow feature is not an ideal choice for anyone living in a home with hard water condition. The mineral of the water will deposit into the shower head surface and it reduces the effectiveness of the head. So, is shower head flow restrictor the one you are looking for?