You can get about the same effect by running the water to get wet, turning it off while washing and then back on for rinsing (the infamous "navy shower").
I imagine the biggest strike against showering with salt water is that you'd need treatment, supply and heating dedicated to the salt tap. And then the salt water is busy corroding all the infrastructure devoted to it.
I wish this was feasible, but in our house the water takes 5 minutes to get to the shower from the water heater, and if you turn it off for more than a minute, you'll get wild temperature fluctuations over the next 5 minutes while it re-achieves a stable mix. I think this is just one more reason to install an on-demand water heater rather than have a giant monolith in your garage.
I wonder if there is a way to better insulate the pipes so they don't lose their heat so much. That's pretty unusual. Five minutes is a long time for water to run down a pipe- you must be running 75ft or so of pipe- so insulation is the other answer (the first being the on-demand water heater in the shower- I used one once and had no problem with it, and it may be more efficient anyway).
Alternatively you could take lukewarm or cold showers. In the very least you save energy, and many claim it is invigorating, better for your skin, burns calories for those trying to lose weight, helps adapt you to cold weather, etc.
Going even further, I switched early last year to not using soap at all (except for extreme dirt which warm water couldn't remove) and my showers are done in 1-3 minutes (depending if I wash my hair or not). My girlfriend also says I smell better (and not like various soaps).
Also related, a chemical engineer from MIT started a company[0] back in 2013 purporting that showering kills our healthy bacteria. Supposedly he hasn't showered in 13 years, although their latest product recommends "rinsing in the shower for 3 minutes" followed by spraying their product on your body.
How much do you exercise? I've heard that athletes often don't need to wear deodorant, because they sweat so much during practice that there isn't a build of of odor causing bacteria.
Usually 2-4 times per week, but mostly just weekends. Definitely not athlete material (anymore at least). When I'm properly sweaty it generally isn't pleasant, especially when it dries.
I should have also noted that I haven't used deodorant in at least 10 years.
Maybe I just got lucky and won the genetic lottery in regards to smelly bacteria.
> I've heard that athletes often don't need to wear deodorant, because they sweat so much during practice that there isn't a build of of odor causing bacteria.
As someone who spends ~3 hours a day doing vigorous exercise, there is no way this is true. I smell awful afterwards.
> It could also be that people who exercise a lot might be less likely to sweat outside of exercise time.
Nope, I sweat pretty profusely throughout the day. Antiperspirant keeps me a part of civilization. FWIW I'm at a healthy weight and in good shape, just genetics.
This doesn't work with electric showers. The element retains heat and the water trapped in it gets extremely hot, so you get scalded when you turn it back on.
In the context of this discussion, retrofitting a heater with a better thermostat would probably be more practical than retrofitting a saltwater shower.
I imagine the biggest strike against showering with salt water is that you'd need treatment, supply and heating dedicated to the salt tap. And then the salt water is busy corroding all the infrastructure devoted to it.