I like your design far better than your architect's. It is a small space, but you have used it well. Would you consider a pocket door at the main entrance to the space? And would you consider having no door at the threshold between the utility closet and the sink? This might open up the space visually, and make it more accessible. Would you also consider a more European look in which the floor is all one piece, tiled, with a slight slope toward the shower drain? I do not think you would need an actual shower door, unless you wished to have it. At a minimum, a Euro-screen would be sufficient. Although they have not caught on in the USA, they give a much cleaner, more open look. Arc and Aqua Uno are, to my knowledge, the only companies that supply them in the USA. I've linked one below. I think you are wise to go with the tankless water heater. My plumber will not install anything else. As soon as mine dies, I will be switching. We have our laundry room upstairs in our current home, something I had always longed for. I love it. Yes, water containment is simple. Not to point out the obvious, but the most effective you thing you can do is to install the best supply hoses money can buy on your faucets, and make sure your water shut off is easy to get to. I have been looking at laundry room renovation, and my plumber tells me this is the biggest mistake he sees people make -- they use basic hoses, and then stack their units with the shut off behind them. I hope this will be of help to you. Here is a link that might be useful: Ark shower screen

Tanem makes a good point on the laundry chute and evaluating how you do laundry. I should have expanded my thinking too as my second floor is for a daughter and grandson, my daughter has gone back to school. So that laundry is for her. When she moves out and that floor is mostly for guests, they can use it when needed. My son will have the basement level, and I was going to put one down there, but decided he can bring his laundry up to the main laundry room. Our master, and everything for our old age is on the main floor so that made that laundry room decision an easy one. When my daughters were both home, and doing lots of laundry, they did their own, so a 2nd floor laundry would have been very handy for them. Especially when they put it in and forget about it. Every time I would want to use the washer or dryer, seems like there was always something already in it. We are still building but I am getting a rack for my front loads so it makes them stackable so the w/d upstairs is a full size, so even if a person only used it for bedding etc, it can handle it. Our old house, laundry was in the basement of a 2 story, with no chute. I would tend to take it all down there in hampers (3 stories) so I was the chute, and I still hated going down there to do laundry. So my new laundry is going to be close to the kitchen also, so I am going to love that. I thought about a w/d closet in the master or close but we come in dirty alot and strip down etc so wanted to keep the laundry over by the mudroom, which is close to the kitchen, so I think it is all going to work out great. I will say though, that we are renting a 1965 ranch, with a laundry closet in the bathroom, with another huge closet for dirty clothes.... now that is handy. There is only one tub/shower in the house, so everyone's dirty clothes are right there. It is a pretty nice set up actually.

I have laundry in the basement-- have a laundry chute direct to the laundry. I have never wanted a laundry on the second floor but have wished that I had it on the main floor sometimes. Advantage to basement--usually have a lot of room (I don't). We can get really dirty sometimes, with gardening and landscaping projects. Can shuck the dirties in the garage or back entryway and drop down the laundry chute there (or in a bucket in the garage)...vs having to deal with them upstairs (where we have carpet). I wash clothes once a week. Smelly dirty laundry is in the basement; not stinking up the bedrooms. I have a clothesline strung in the unfinished part of the basement for drying rugs, mattress pads, sheets, jeans, etc. during the winter/ rainy days. As well as drip dry items that don't go in the dryer. The clothes line is also handy for hanging wet or damp dirty items to dry (like bath towels & kitchen towels) before they go into the dirty clothes hamper. I fold & sort items as I unload the dryer. Towel stack to the linen closet, DS's clothes in one stack, etc. Usually cart the basket to the main floor and someone else will haul it on upstairs. Have had three laundries that were in enclosed back porches and one just adjacent to the garage when I lived in the south. That arrangement worked really good and would be my preferred location for a laundry. Would not want W/D in a closet if it can be avoided. I use my laundry sink a lot as well as having the washer drain hose empty into the sink. (With a lint sock to keep lint and dog hair out of the sewer line--septic leach field if that's your situation.) You adapt to wherever the laundry is. Pros & cons to wherever it is. Main thing is that a home laundry beats the heck out of having to go to the laundromat! We've probably all had to do that at some time in our lives.

Maybe the OP can decide what size machines suit his/ her laundry room ;-) One of those Whirlpool machines costs more than the Miele, and both cost more than the Miele which comes to the market next month. I’m not advocating any particular brand, but the other significant advantage for the Miele in an older house is that it does not require a 220v receptacle, which every other electric dryer will. That’s another savings. An old house with stone walls and a slate roof is not without its challenges when it comes to adding amenities. That’s where I do think this particular appliance could make a lot of sense for you. Good luck!