Fallout 4: Simple Infinite Purified Water Farm

Date: 2024-05-01 | create | tech | video-games | fallout-4 |

Fallout 4 is a game about survival in a barren wasteland. Finding reliable sources of key resources is crucial for staying alive and avoiding frequent resource grinds.

Unsurprisingly Purified Water is a crucial resource for post-apocalyptic humanity. In Fallout 4 this is both a decent healing item and a pretty good cash crop with a Value:Weight ratio of 40.

In this post we'll go over a simple method for farming infinite Purified Water - providing an infinite supply of both healing items and money (bottlecaps).

Farming Purified Water

We'll be farming Purified Water in this post. This is a good resource for a few reasons:

  • Easy to Farm - Just needs 1-2 base items (and no settler requirements)
  • Scales Well - Can get to 10+ generators pretty quickly leading to lots of resources
  • Valuable - Decent Value:Weight ratio (40) and doubles as a good healing item

How to Farm Purified Water

There are four settlement buildings that produce Purified Water:

  • Water Pump - 3 water per day
  • Water Pump (Powered) - 10 water per day, requires 4 electricity -> I recommend skipping this one
  • Water Purifier - 10 water per day, requires 2 electricity (small generator)
  • Industrial Water Purifier - 40 water per day, needs 5 electricity (medium generator)

The Water Pump can be built anywhere and doesn't require electricity or a body of water. The Water Purifiers do need electricity and a body of water to function but the tradeoff is they produce a lot more water. Not all settlements have a body of water but there are several including the first settlement you get (Sanctuary) so you can start this production line right away.

Your settlement will produce water every day-ish and about 75% of the surplus water will be stored in the workshop inventory.

Surplus is generally calculated as WaterProduced - SettlementNeeds.

Note that there is a relatively low cap on workshop producable inventory. Once the workshop stores enough to reach that cap it will stop producing that resource entirely. This means you will want to regularly take the produced water from your settlement to ensure it keeps producing.

We'll talk about some ways to efficiently work around these constraints in the next section.

Tips for Effectively Farming Infinite Purified Water

We now know how to farm infinite purified water but there's a few more things to keep in mind to keep your farm running efficiently.

Build water generation as you go - Water generation systems can be expensive, requiring some relatively uncommon scrap components. Don't worry too much about building it all in one go. Instead, gather scrap as you play the game and build up your production each time you return to your settlement. You'll have more water than you can use pretty quickly.

Regularly take generated water - Water generation will stop once the workshop reaches the relatively low resource cap. This means you'll want to regularly take any generated water so it will continue producing. My system is to take the water whenever I return to my settlement - usually for repairing or upgrading gear. It only takes a few seconds and ensures everything continues to run smoothly.

Keep some water on you, sell the rest - Purified Water is a great healing item made even better now that you have an infinite supply. I like to keep ~20 on my character for use as an over-time heal and sell the rest. You'll quickly have WAY more water than you know what to do with (like 100+) and you can sell them at vendors for a pretty good sum - allowing this farm to double as an infinite money farm.


I've been thoroughly enjoying returning to the wasteland in Fallout 4. The base building mechanics are lacking compared to games focused on that but they provide some interesting side mechanics and possibilities to play around with.

Q: What's your favorite kind of base / factory to build in Fallout 4?

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