Beginners guide to water productionVery early on in the game you will have to build out the Sanctuary settlement and add various resources to make your initial settlers there happy. Part of this is building two water pumps to meet your settler’s needs. If you come back to this quest later (around level 7-10) you should have enough resources to build a Water Purifier facility in the river south of the houses in Sanctuary. This will provide more water than you need for your settlers and all the excess will be stored in your Workshop as Purified Water. You can come by every day or two of in-game time and just pick this up to have as great healing item in the Commonwealth.
Regular Water Purifier requires 2x Oil, 2x Ceramic, 5x Rubber, 2x Copper, 10x Steel, and 2x Cloth. These are fairly commonplace and you can get them by scrapping stuff already in your settlement. You will probably have enough materials to build several, which will make more Purified Water for you (I recommend at least 2). You will also need a Power Generator to power these Purifiers. Don’t forget to connect a power wire between them!
If you build a large number of water purifiers you will have so much Purified Water that you can sell it at vendors for extra bottlecaps. With perks that increase your barter you can make couple of thousand caps every few days this way. Important thing to note is that you should have your settlement defenses higher than your water+food production or you might get raided a lot.
Advanced water production
You are a dedicated settlement builder and have invested into Charisma heavily to have access to building supply routes and shops for your settlements? You based your build on access to perks that grant the ability to build everything for your settlement? Purified Water production will pay back even more for you. Sanctuary is a great settlement in this regard because it has access to open water, which means you can build an Industrial Water Purifier. You can do this in any settlement with access to open water. It provides 40 water production for 5 power and requires the following materials to build: 4x Oil, 2x Ceramic, 10x rubber, 4x Copper, 20x steel, 4x Cloth and 6x Screw. Most of these materials can be gained from scrapping stuff at Sanctuary, like houses and tires for rubber and steel. You can get Oil from Gas Canisters and Ceramic is scrapped from toilet bowls or coffee mugs. Screws can be salvaged from your unneeded weapons, if you have the Scrapper perk (INT 5), or from scrapping Desk Fans, Globes, Typewriters, Toy Cars and such.
Road to high profits is having two points in the CHA 6 Local Leader perk and building stores in your settlement. Collect Purified Water from your Workshop inventory and sell it to your own vendors. You will get better prices and you will get a small tax bonus for each item you sell. All of the extra bottlecaps from you selling your own settlers purified water will be stored in the Workshop and can be picked up every day or two. This way you maxed out the efficiency of water production’s usefulness.
We would like to thank jredwards for posting this topic on reddit and sharing the water purification tip as well as Auparo