AITA: Navy Showers at Parent’s House

Am I the asshole Navy Shower Edition. I (33F) am married to my husband (42M). We have two young boys under 5 and live out of state from my parents. It's about a three hour drive to their house and we visit fairly often. They have a larger home in a beautiful neighborhood and they have very well paying jobs. Since we have young kids, we often stay for the whole weekend. My dad (58M) is ex-military and grew up taking "Navy Showers" as he calls them. My grandfather always made my dad and his brothers as well as anyone else who stayed at their house take them as well. It's essentially a regular shower except you turn the water off when you're soaping yourself up and shampooing your hair. So you'll turn the water on to start the shower then turn the water off to soap up and shampoo your hair and then turn the water back on to rinse off. My grandfather always said it saved tons of water and was efficient. Growing up, I always thought it was ridiculous because it just meant you were standing there freezing while the water was off for half your shower. My dad always rolled his eyes over it too. Just this past weekend though, he told my husband and I that we needed to start taking navy showers when we visited. He said my husband takes too long of a shower while he's there and it's wasting water so he wants us both to do them. He and my mom both shower that way everyday because he believes it saves water and is better for their septic system. It should be noted that my husband is not taking long, luxurious showers for fun. He is balding and shaves his head in the shower every morning to prevent stubble. His showers are roughly 20 minutes long and again, it's because he has to shave his head. Anyway, my dad told us this and we both politely said okay. However, later in the day he brought it up again and I told him I thought it was a little ridiculous to stand in a freezing shower without water just to save, at most, 2 minutes worth of water. Not to mention my husband would be turning the water on and off every time he needed to rinse his razor. My dad just repeated that we, but especially my husband, takes too long of a shower. He claims my husband takes 30-45 minute showers while he’s there. I explained that my husband has never taken that long of a shower and that it’s a little weird to be monitoring the length of our showers. I told him that it makes us both, but especially my husband, feel awkward and we both feel like we are being judged. He wouldn’t budge and just repeated he wanted us to shower that way while at his house because he believed it was better. We, of course, respected what he said and did the navy showers this weekend, but AITA or is it actually a ridiculous request?

It should also be noted that we all live in the Midwest and it was 12 degrees out this weekend with snow and they keep their house at 67 in the winter so standing in a shower when you’re completely wet without the water running really sucks. My parents are well off so it’s not a money issue either. I don’t mention them being well off to say that therefore money doesn’t matter. I just wanted to provide context.

Edit: my husband and I both respect my dad a lot and will absolutely follow the navy shower rule when we are there. I'm actually very close with my dad and he and I have always had a great relationship. I am in no way going to disrespect his rules or stop visiting. I am not even angry about the new rule. At the end of the day, it’s their house and my husband and I respect them enough to follow it. I just think it’s a weird request from them.

Edit 2: I know 20 minutes isn't a quick shower. I take about 5 minute showers myself.

Edit 3: My kids and I visit frequently, but my husband only stays overnight 1-2 times per year. He has a crazy work schedule so he’s not able to come for overnights as often so his showering habits are only an issue 1-2 times per year.