My relatively small (24-person) vault seems to have an abundance of power, but a major water and food shortage! I've tried building more water treatment plants and diner/cafeterias (although they're minimally staffed), but my vault continues be in a state of perpetual shortage.

Everyone's miserable! I feel guilty.

I'd appreciate any tips or rules of thumb to determine how many of each type of room I should build...or general advice on how I seem to be messing up.

  • I don't think there's any point in having more or larger rooms if they're understaffed. Better upgrade your rooms and make sure they're fully staffed. Jun 24, 2015 at 9:08
  • It more cost effective to upgrade merged rooms so it is better to merge first than upgrading before merging. Jun 25, 2015 at 11:56
  • Kids seem to use up water and food more than adults, and on top of the fact that they do not work. You should check how many kids you have and try not to have too many kids pop at the same time.
    – Nelson
    Aug 23, 2015 at 8:47
  • FWIW, I'm running a vault with currently 68 dwellers on "single", fully upgraded and staffed triple room of the basic type for both food and water, but I need 3 upgraded triple power rooms to keep the vault going comfortably. Don't expand too fast (ie., build more rooms than you need)!
    – Freso
    Nov 10, 2015 at 9:44

5 Answers 5

  • In the beginning (up to about 50 dwellers) you should have about an equal number of each production room type, so one power for each food and water.

  • When expanding, you should usually build the power room first, so that you have enough power to activate a new food and water room.

  • Extending a room (i.e. building a new one next to an old one) is more efficient per dweller than placing singles.

  • Just building a room doesn't make it produce anything, it is actually only a dweller's stat that produces something. For example, in power rooms the production comes from the strength stat. One power room with three strength 3 dwellers will produce the same as one power room with one strength 9 dweller.

  • Rooms produce depending on the amount of the main stat, not the number of rooms. So for example, one power room with dwellers totalling 10 strength will produce the same per minute as two power rooms of equal size and level as the first room if they contain a combined total of 10 strength. However, using two power rooms instead of one will cost more to build!

  • To make dwellers happy, keep them in the room they have the strongest stat in (their "talent"). If two stats are equal, the left stat takes precedence (left in the sequence "S-P-E-C-I-A-L"). You will see if a dweller likes a room by the green corners of the room when you move a dweller to it. You can also make dwellers happier by successful rushes (but sadder by failed rushes) or by making them have children (both parents).

    • The main stat for a dweller includes any outfit bonuses. This means that you can use outfits to change which room a dweller prefers by giving them the right outfit. This is important, since it is more important to keep your production balanced than it is keeping your dwellers happy, but by using outfits you can achieve both!

There is not really a formula for this. I normally try to get everything in balance. I normally build slowly. Just add one room, and upgrade it to the top. Wait for the result (some minutes) and see if your trend in a stock goes up or down.

Mostly it is more helpful to train your dwellers in the right stats to improve the efficiency of each room and to lower the accident rate for rushes. This is more important than a lot of rooms. By the way, don't let dwellers alone in one room. Their happiness will fall down. If they work with someone else in the same room, they are much happier. But in your case it's just the water/food problem.

You should stuff 2-3 people in each dinner and water supply. If you're still on a shortage, build the next room, upgrade it and stuff it.

  • I've noticed there is a 2-person limit to each room, regardless of the level (which doesn't make sense to me - if I can see a diner with 16 tables, why can't I put 16 people in there!?). So for three merged rooms you can only put 6 people in the room. Jun 24, 2015 at 10:55
  • Yes this is right. You can merge the rooms to get up to 6. This is good, but mostly not needed 2-3 per room work efficiently enough. I only use the max number for my training rooms.
    – Ionic
    Jun 24, 2015 at 10:58
  • More people, faster resources. A room with 6 people with the same stat level will be twice as effective than the same room with only 3. Jun 25, 2015 at 11:57

What I do, is that I build rooms for the amount of people there are. What I mean by that is if I have, say, 15 dwellers, I would have 6 individual resource rooms. 3 Dwellers would either be two are populating the vault, or going out into the waste land. Add up every resource room you have, and divide it by 3. What you get is how many rooms you should have per category. Any more and you run the risk of wasting your power, any less and your vault is not running at top efficiency, however there are exceptions.

Put the best people into their proper rooms, and it's a generally rule of thumb to combine rooms and then upgrade, as I've noticed that if you upgrade a room and then combine it it (seemingly) loses the upgrades you gave it.

In your situation, you would use seven people, and four rooms per resource category. Three of your people should be bumping uglies or out in the wastes. Give the people in rooms that are understaffed better weapons and better SPECIAL stats, as these people will need a boost, and you will need to rush these people, sometime disregarding the almost-certain probability of failure. That's why they have better guns; almost all of your rushing should be done in those rooms, if not all.

If you need more resources and you have extra people, go ahead. Build more rooms, but make sure you got the caps to upgrade those rooms right away.

That's generally what I do, and it works out well for me. I haven't gotten too far, but my vault never once dropped in the red, so that's great. Happy Surviving!


I was having a lot of trouble and couldn't get past 10 or so people without everything going to crap. So what I finally figured out is to built a single unit power, water and food room and staff them adequately with 2 people and send one to the wasteland (checking up on them to make sure they weren't dying). Once I got my resources up to speed, I added only 1 more living quarters and had one pregnant woman. I didn't build anything else until my resources were at peak capacity even though I had the money. I added very slowly to my rooms, making my power room bigger, then my water, and then my diner. I did this slowly, as I began getting new dwellers so I could adequately staff my rooms. I didn't build a medbay or a science lab at all until I had a 3-unit power, water and diner with full staff. You don't really need stimpaks or radaways this early in the game anyway, and if you check up on your explorer regularly you can pull them back before they die.

Now, as far as having kids goes, I never have more than one child at a time, because they utilize water and food without contributing. I would wait until one baby was born and then have another pregnant woman, so that way I only had one pregnant woman and one child. The pregnant woman won't fight, so having too many isn't a good idea. And then once the child is grown (3 hours) they can work in a room. Since it takes 3 hours to have a baby, this is a cycle than I find works well. If I don't have room, I don't have a pregnant lady, and I only build as I need so there aren't rooms using energy that aren't being used.

I also made sure to put the people with stats matching the rooms. And if I got an outfit than increased a stat, I'd put in on the appropriate person so they would decrease the time a room takes to make a resource.


This guidance applies to Survival mode, so it will also more than cover regular games as it is very conservative:

Basically, getting up to 30 dwellers is critical, as, with 30 dwellers, you have training rooms available for Strength, Perception and Agility and Intellect.

Start your base by concentrating on building exclusively 1 each of a full sized (size 3) Power room, Diner and Water Processing plant - expanding your living quarters as necessary. That covers the first 18 dwellers.

You will need (on Survival) stimpacks, so you also need a size 2 medical room that you will populate with the next 4 dwellers.

With this many dwellers, the training rooms will start to unlock, so a size 1 Weight room, Armory etc, each stocked with 2 dwellers.

At this point your production rooms will NOT be producing enough. Don't panic. Whenever the % chance to fail is near or below 30%, rush the room immediately after collecting. This effectively doubles your production and makes dwellers happy, providing a further boost. As and when the dwellers in the training rooms level up, drag them over their production room and drop them there if you see a "+1" or more. This automatically swaps the dweller with the dweller with the lowest stat in the room and is thus very effective at minimizing training times and growing the total number of relevant SPECIAL in the room to boost production.

Your (potentially) survival base now has 30 dwellers, all dedicated to principal production (6 in each room) and stimpacks (4), or training up on S,P,I and A (2 in each size 1 room).

As soon as the minimum skill level in each room reaches about 4, production will start to exceed use. Yay!

At this point you can start building more diners, power plants and water processing rooms - that you will leave unstaffed: Use elevators and a zig zag pattern to ensure that disasters in these rooms cannot reach other rooms or your occupied area. These rooms allow your (now) excess production to be stored which act as an excellent buffer to use while you log off / loss due to raids etc.

If you are playing survival, you can now breed 5 more dweller to get the total to 35, an get a fitness training room and train their Endurance.

But with these initial 30 dwellers committed, your power, food and water requirements will be stable and you can (now) take a breather, and start to expand how you choose.

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