Peeing in the shower is another fine way to save time, money, and water. A new toilet uses about two gallons of water per flush, toilets from the 80's use about 3.5 gallons and older models anywhere between 5 – 7 gallons. Even if we assume everyone has a newer model toilet (which they don't) and showers once a day (because most Americans do), peeing in the shower could save upwards of 730 gallons of water a year per person. With over 300 million people in the U.S., that's a whole lot of water being saved! Plus the toilet paper not being used for those of us that wipe after we pee.
I read some other articles about how peeing in the shower is fun, helps you prepare to pee in the woods and helps you improve your aim. These made me laugh at first, but as a hiking guide that has to deal with lots of folks unskilled in this area, having them practice in the shower might not be such a far fetched idea after all. Better to practice squatting and aiming in the shower before you're out there peeing on your hiking boots.