I've put over 60 hours into Fallout 4 settlement building. One of the most frustrating things for me is the lack of information for finding out certain things. Sure, some elements of building settlements in Fallout 4 are fairly self-evident, but some elements certainly are not. As such, I've created a short Fallout 4 guide of some tips I think would helpful for people who might not have spent the insane amount of time messing around with settlements that I have.
1. Tato, Corn, Mutfruit, and Purified Water can be combined to make Adhesive
Okay, this one is so well known that it's practically a joke in the various Fallout 4 communities out there. But hey, you might not know what I know so I may as well open with a common one.
Adhesive is one of the most important substances for crafting weapons, armor, and power armor. You're going to need it to make nearly everything and it can be rather expensive to acquire it through purchasing junk. (Many players have been observed talking about mugging a certain individual in Diamond City with a roll of duct tape on his belt.)
Your settlers are going to need food anyway, so you may as well grow something that has a dual purpose. Adhesive is just one of those things that you're always going to need. The only way you don't need it is if you entirely stay away from item crafting, and honestly some of the weapons and armor you can come up with are so much better than the random things you pick up. It's a pretty important part of the game in my eyes.
2. Water Purifiers occasionally deposit bottles of Purified Water in your Workbench.
I always stashed Purified Water in my workbench anyway so I never noticed this until I came across a comment on a forum. Every Water Purifier you build (not the low-end hand pumps) will put a certain amount of Purified Water in your workbench every few days.
Purified Water sells pretty well and it's also a part of the Vegetable Starch recipe, which can be turned into Adhesive.
Furthermore, Water Purifiers in Fallout 4 operate entirely autonomously. Plunk a water purifier down in some water (and yes, unfortunately it has to be sitting in standing water), hook it up to a generator, and you'll have Purified Water dumped into your Workbench on the regular. No need for settlers to work it or anything like that. Some coastal locations have room for many water purifiers and it wouldnt be a terrible idea to build a whole bunch of them solely for the purpose of selling the water you produce.
3. Modified Pipe Guns don't typically sell well but they can be an invaluable source of Copper.
Copper is another one of those resources that you can never have enough of—especially if you're the type of person that's wiring their settlement up like an amusement park.
A lightly modified (or outright standard) pipe weapon will net you maybe 20-40 caps. You'll get a few pieces of Steel (at least) if you decide to scrap it instead. However, all of those fancy attachments can start to net you other components such as Copper and Screws. I rarely sell my pipe weapons anymore as they're just so gosh darn common and I'm always burning through resources with all the crazy settlements I'm building in Fallout 4.
I'd generally advise against buying pipe weapons solely for the purposes of scrapping them. However, you're going to be coming across so many of them throughout the course of normal gameplay that you're going to inevitably end up with literal piles of the things. You could get a handful of caps or you could just scrap them for some much-needed resources. The choice is yours, but consider it carefully! It might just be more valuable than the paltry amount of caps you'd get for them instead.
4. There are a whole bunch of useful world objects under the Miscellaneous Resources category.
If you go to Resources and then go to Miscellaneous Resources, you'll find some very useful tools for your settlement.
The Scavenging Station can be worked by a settler to slowly produce materials used for crafting and building. Each settlement has its strengths and weaknesses in terms of what you can build and how you can best put your settlers to work but Scavenging Stations are useful everywhere.
The Brahmin Feed Trough looks just like a bathtub because, well, it's a re-purposed bathtub. However, what it does is attract the Brahmin in the settlement to stand there and eat rather than wander around. They can sometimes be an annoyance and so it's a good idea to keep them all in one location.
The Bell allows you to call all of the settlers to one place. This is useful for assigning work or merely gathering them all in one place.
The Siren is much like the Bell except that it acts as an alarm. Settlers will run to the Siren with their weapons out ready for a fight.
The Fast Travel Target is arguably one of the most useful things here. Some settlements are quite large and you may not build near the default fast travel point at all. You no longer have to run from the front gates all the way to your setup!
5. You can (and should) link up settlements with caravans.
Once you have multiple settlements you can assign a settler to travel between two locations. The settler will change their title to Provisioner and travel between the two settlements with a Brahmin. You may occasionally encounter them en route out in the world.
Linking settlements together creates a network where resources are shared. The ideal is to link up all of your settlements. Storing a resource in your workshop makes it available at all of your workshops. This make crafting and building much easier and reduces having to bounce around between different locations.
6. You can power structures and locations by attaching power conduits to the walls or general area.
Some items such as floodlights require a direct wire connection to work. However, some objects just need to be in a powered area. You can accomplish this task by attaching a conduit to the wall or floor near where you want to place the object and then attaching a wire to your power network.
The radius isn't terribly large so you may need more than one conduit to cover a building. The houses in Sanctuary will often require a few strategically placed conduits to power the entire building. This isn't strictly necessary, but if you want to light up the interior of buildings (whether they're pre-existing structures or your own creations) you'll have to slap some conduits on the side and wire them up.
7. Shops slowly generate caps for you and refresh their inventory every two days or so.
Another type of workstation you can build is little shop stalls that settlers can man. There are six types in total with three different quality levels. You won't be able to build the best kind until you reach Level 20 and unlock rank 2 of the Cap Collector perk but it's absolutely worth it for a variety of reasons.
Some of the larger stores have a pretty big upfront cost—building one of each will cost you around 10,000 caps. However, they make an excellent place for unloading your wares when you need to resupply. And heck, you can live the capitalist dream by selling the crops and purified water back to the people who made them.
Aside from providing the invaluable resource of a place to sell your stuff, the stores will also slowly generate Caps in your workbench. It will take many, many in-game days to ever make your money back from the initial building costs. However, this is a totally passive way of earning money, and it's worth the investment in the long run.
8. Magazine Racks can display the skill books you pick up throughout the game.
The Bobblehead Stand is pretty well known—you can display the Vault-Tec Bobbleheads that you pick up while playing Fallout 4. Something similar existed in Fallout 3. However, you might be surprised to learn that there is also a Magazine Rack that lets you put the various skill books on display.
The Magazine Rack is only for displaying skill books and is not able to hold anything else. It's a nice option if you like to easily keep track of all the books you've collected or merely put them on display.
9. There are skill books for the building portion of the game, too!
You may know that there are skill books that will give you certain perks such as +5% critical damage with guns or +10 to companion carry weight. However, there are also more mundane skill books that add new things to build in settlements, such as picket fences and high-tech lights. Now you can recreate the dream of suburbia in post-apocalyptic Boston!
Just as an aside, there are also other cosmetic skill books that can add new things such as tattoos and hairstyles if you're into changing your character's look every now and again.
10. Named NPCs and companions can work, but they're not necessarily the best choice for the job.
Mild early game spoilers ahead: the initial batch of settlers in Sanctuary are Codsworth, Preston Garvey, and a handful of named NPCs that you rescue from the Museum of Freedom in a mission you probably will tackle in the first few hours of the game.
You can assign these people to do specific jobs, but part of the background world building is that these NPCs will "work" on the houses and do various other things. This, in effect, also means that they abandon their stations. I had hoped that perhaps I could get some of them to shut the hell up by having them man Sanctuary's stores but it just didn't work out.
If settlers don't have a job they tend to default to working on the crops. Let the named NPCs work on your crops and assign the other tasks to unnamed Settlers.
Welp, that's it for my Fallout 4 settlement building tips! I hope you've found them useful!
This is by no means a comprehensive guide. However, unless you have a crazy amount of time in the game I'd bet a hundred Caps that you probably didn't know at least one of these. It's just so darn difficult to track some of this information down. It's made especially difficult considering that Fallout 4 is still pretty new and some of the larger sites out there have leveraged a lot of techniques to get their stuff to the front page of Google searches.
If you're looking for more tips like this, I'd advise that you go to Fallout 4 communities like the /r/fo4 subreddit and sub-boards on places like GameFAQs (PC, PS4, and XBox One) and the Fallout 4 Steam Community. You might have to look around a bit, but you can generally find an answer to most questions or a solution to most problems. And hey, if you don't know - ask! Someone is usually glad to help you.
Did I get something wrong here? Do you know any other really cool tricks that other people should know? Share any other tips you have for Fallout 4 settlements in the comments below!