Filter Housings Big Blue are for mains water and tank water whole of house.
The blue housings can be kept outside in all types of weather. We do suggest you put a box or cover over them or keep it undercover to protect them.
The white housings need to be completely out of the weather because they aren’t designed for the weather components. We also suggest rinsing the big blue housings and white housings out when you replace the filters. The O rings inside should be coated with a silicone gel to preserve them and if the O rings get squashed, replace them.
Do not over tighten the housing lids- just hand tight will be sufficient.
Pressure gauge are available so depending on model/brand of the filter housings big blue.