Any showerhead now manufactured in the United States is required by law to release no more than 2.5 gallons of water per minute. You can test it by putting 10 drops of food coloring in the tank. Don't flush for 15 minutes. If the colored water shows up in the bowl, the tank is leaking. Use the wastebasket instead of the toilet for trash such as facial tissues.
Some people thoughtlessly flush away tissues and other bits of trash in the toilet.
Using a wastebasket, instead, will save all those gallons of water that otherwise go wastefully down the drain. If someone in your family likes to shave with water running in the basin, they probably use at least one gallon per minute, most of it wasted. A stoppered basin needs one-half gallon or so of water for adequate razor rinsing. It's a great water conservation technique. Don't let the water run when you brush your teeth or when washing your face.