Your residents will expect a certain level of comfort and security from the settlement which will be affected by a few different parameters. Happy settlers are more productive and spending time to improve ratings will yield significant rewards over time. The status of a settlement depends on a combination of the following factors:
People - The number of people in a settlement.
Food - How much food the settlement is producing.
Water - How much water the settlement is producing.
Power - How much power the settlement is producing.
Defense - The defensive strength of a settlement.
Beds - The number of beds in a settlement.
Happiness - The overall happiness of a settlement’s residents.
PipBoy Workshop Management - The PipBoy has a handy feature where you can check on all the settlements under your control using the Workshop tab. Should any rating fall below the required standard, an alert will appear near any settlement with the substandard rating. Select a settlement to check on which ratings have fallen below the threshold.
The number of people in a settlement goes hand in hand with how many beds and how much food and water your settlement will need. People are a valuable commodity though because many workshop items can only be used when a worker is assigned to an object. If a worker is not assigned a particular task, they will automatically generate salvage, providing a steady stream of building materials to the settlement. Use the Workshop to issue commands to a settler. They can be assigned to beds, salvage posts, watchtowers, stores and much more.
Though settlers will be drawn to more established settlements, populations will still increase slowly without building a radio beacon. Use a beacon to increase the number of people at key locations but also be on the lookout for characters you encounter on your travels, some of whom you can recruit to your settlements.
Charisma - Your Charisma rank determines the maximum population for a settlement. One Workshop can accommodate 10 settlers plus one additional resident per Charisma rank. There will be no new settlers once this maximum has been reached.
Interacting with settlers is a good way of acquiring quests, items or just listening to their concerns which may give you hints about what a settlement needs to improve on. Trading good equipment with settlers will allow them to be much more effective in combat, though it has no impact on a settlement’s Defense rating. Settlers can also sometimes commandeer items that are left out in the open, even unused Power Armor should you leave it lying around with its Fusion Core intact. You can reclaim these items easily enough once you identify the person but simply storing valuables in containers and removing Fusion Cores will prevent them from making off with your property.
Once you have invested in the Local Leader perk, you can then assign a settler to a supply line. Two settlements connected by a supply line can share food, water, and any building materials stored in their Workshops. The settlers you assign will move back and forth between the settlements on the supply line, collecting provisions along the way. To cancel a supply line, just assign the worker to a different task.
Not every person in a settlement can be assigned to work or relocated. The available options depend on the person but as a general rule, key figures like settlement leaders or companions tend to be less flexible. These people will still count towards a settlement’s population however.