
Start with the former, unlock the latter at 80 dwellers. Water treatment plant / Water purification plant – Creates and stores potable water.Start with the former, unlock the latter at 70 dwellers. Diner / Garden – Produces and stores food.Start with the former, unlock the latter at 60 dwellers. Power generator / Nuclear reactor – Makes and stores power.Note that power, water, and food can only be capped at your max facility’s storage limit, so building an extra square or two of these can increase your storage capacity, preventing service disruptions.

Production rooms – Necessary resources for the vault’s survival.


Utility rooms – Required for vault function. Rooms can be categorized by function, thusly: Most rooms can be expanded to 3 sections wide and later upgraded. Be careful not to overbuild, because rooms left empty tend to attract disasters. Over time you will need a good balance of rooms to provide stable function levels. The rooms are what your vault is made of, so plan them carefully.
