In the United States, new shower heads are limited to 2.2 Gallons Per Minute (8.33 Liters Per Minute). The applicable law went into effect in 1992, so older heads might use more. Low-Flow heads also...
This really depends on where you are and a lot
of other factors. A minimum acceptable flow rate for a family
of 4 would be about 3 gallons per minute into the well.
A "good" (good flow rate, we...