I had actually planned to make a sort of airlock, change clothes, and ventilate the basement only through HEPA filters. I don't want to cultivate 100% mushrooms there, but rather more noble ones so that the effort is worth it. The mushrooms would also undergo a seasonal simulation so that they are ready to harvest after just 3 months. This only works if you have very high humidity and can adjust light and temperature.
However, I just realized that if the pond water seeps through the walls, spores of mold fungi could also pass through. Or is the concrete fine enough to filter them out?
The property is not yet available; since this is an experiment, it will be built in the middle of nowhere anyway. Far away from any children.