How do I choose materials for concealed water supply piping in a new building?

Actually, when choosing hidden water supply piping, you should focus less on the material itself and more on the conditions in your house and your future plans. Different materials handle the job well, but each has its own pitfalls when installed hidden, and pulling it out later will be really difficult.

Metalplastic is a popular choice in new buildings - it holds pressure, isn't bothered by temperature fluctuations, and it's flexible. The downside is that fittings can degrade over time, and you'll have to deal with maintenance. Polypropylene requires soldering during installation, but it lasts a long time and doesn't need servicing; however, with hidden installation you need special care with fastening so the pipes don't rattle. Copper is expensive, but it's essentially a material for life - no replacement needed and looks substantial if your budget allows.

The main thing with hidden piping is not to rush into choosing a material until you see what the builder is using in the building's common areas and what piping layout they've already done. Often it makes sense to go with the existing house infrastructure. And definitely think about access to the piping location later - if the pipes are in the wall, calling a plumber when there's a problem will cost you significantly more than if everything was exposed.