Like me, you may be wondering exactly what the secret formula is behind the defense system for settlements in Fallout 4. Initially I thought the amount of defense your settlement has had to be equal to the amount of settlers living there, but I was wrong. If you’ve been building up tons of turrets and posts and have no idea why your settlers still aren’t satisfied, here’s why: your defense needs to be equal to the sum of your food and water. Food and water are the commodities that make your settlement attractive to would-be invaders like Gunners, Raiders, and Super Mutants. That is why a neglected settlement, one that has been through a battle without your assistance, will often have destroyed crops and water pumps. Since you have to repair those items by lugging food and equipment back to the site, using resources you could have otherwise used to build more defenses, it makes sense to have your settlement adequately defended in the first place. If you have 10 in Water and 15 in Food, that means you need 25 in Defense, even if you only have 3 settlers. In the example in the photo above, Abernathy Farm has 17 in Food and 15 in Water, which means that at 27 Defense, they are at a 5 Defense deficit. Don’t forget to check the Workshop tab under the Data menu in your Pip-Boy to check out what settlement is in need without having to travel there first.
Prop-tip: invest in all those Strongback perk subranks. The ability to run or fast travel while overburdened makes improving your settlement a much easier process. For more on that, check out our guide on S.P.E.C.I.A.L., perks, and the ideal character build for Fallout 4.