You don't need a shower or hot tub for that, there are online noise generators with hundreds of different flavors such as https://mynoise.net/ - I prefer music most of the time however, the "rain sounds" are so relaxing that they make me sleepy...

Yeah, I use a sound machine at home for sleeping. We started with our kids when they were babies, then decided we liked having one in our room as well.

Haven't graduated to having one in my office, but maybe I should give that a whirl. Though one thing the shower & hot tub still have is temperature comfort. Warm and relaxing might be as important as the noise.

I’ve been programming to their rain on tent. I don’t get sleepy, but it’s a little jarring when I pull off the headphones, I want back in my tent!