No one likes contaminated water, so it's best you fix things up when you find out the water supply is tainted in Arc Raiders. The Source of the Contamination quest asks you to figure out what's causing the issue--and while it may seem pretty simple at a glance, it can be a little tricky to figure out the exact spot where things are going wrong with the water. Below, we'll fill you in on where to find the Flood Spill Intake on the Dam Battlegrounds map and how to solve this mystery.Be aware that you don't need to extract with any items during this quest. Since you'll merely need to visit the location below and interact with an item, it's not a bad idea to handle things with a free loadout so you're not risking any of your hard-earned resources while exploring here.Where to find the Flood Spill Intake at the Water Treatment CenterThe Water Treatment Center is found just to the left of the middle of the Dam Battlegrounds map. It's a popular spot where a lot of raiders tend to visit to loot and fight, so it's probably best for you to approach it from the swamp if you're trying to keep things quiet. This is also a good call in general since the Flood Spill Intake is on the exterior of this POI.The Flood Spill Intake is on the northern part of the Water Treatment Center facing toward the swamp. It's not too hard to spot as you approach.Flood Spill IntakeYou'll know you've reached the right spot when you see concrete walls containing polluted water. Once you've reached this location, make your way down into the gross water.Here's where you'll find the source of the contamination.In the water will be a barrel, which happens to be the source of the contamination you're searching for. Interact with this suspicious object to defuse it. This completes the quest.You can now leave the raid by using the Central Swamp Lift to the north. However, while you're here, it's a good time to peruse the various structures in the swamp for loot or check around for mushrooms, the latter of which can be found growing on trees all around this area. You'll need at least twelve of them to complete all of Scrappy's upgrades back in Speranza, so you might as well start collecting them, considering that they're fairly hard to come by.Next up, you'll need to complete a quest called Switching the Supply. You can also check out our full Arc Raiders quest list to find out what else you'll need to handle while exploring topside.