@mmeqcenter, a very useful analysis. Thank you. As you noted, you have to figure out the gallons per minute for the nozzle you’re using. And in any event, you can then figure out the cost per minute and then the cost per task. I’ve gone down that rabbit hole!
To give shampoo baths that use less water here are some tips: Think Navy shower. My relatives in the Navy taught me that water conservation is key when at sea, so to shower they would wet themselves down, turn off the water, soap up then turn the water back on to rinse.
Make the folks in your barn do that with their horses, rather than let the hose keep running while they soap up.
Dilute the shampoo half and half with water before using it on a horse that’s been wetted down. Try this with your hair washing sometime. You’ll find that it suds better, cleans just as well, rinses out better and leaves less residue (resulting in shinier hair). Shampoo is waaaay concentrated for its job to keep it from running all over the place. If you’re squirting some shampoo on your self or your horse, and then working it into suds (on my horses, I do this with a relatively soft plastic brush) the liquidity works in your favor.
After sudsing up your horse, use a sweat scraper to take off most of the dirty soapy water. Then rinse with much less water than you’d have used otherwise.
We put a large water tank on a cart right next to the barn. As soon as the town announces water restrictions, all buckets get emptied into the tank and we use the “gray” water for new plantings, watering the ring (every little bit helps) and just raising awareness of how much water gets wasted.
Hope there are more tips. I’m in coastal Massachusetts are we’re already in a drought. Spring isn’t even fully here yet. It’s going to be a tough year for sure.