I finished the main quest with not putting the FEV in the water, thus not killing every infected/mutated being on the fallout plane.
I was wondering what would hapen if I did?
How does the gameplay continue than? do u work for the enclave or stuff
Its hard to find this answer on the internet, and I am really curious.

Basically, all the NPCs are miserable, and if you drink more than a bottle or two of Aqua Pura (before it's effects wear off) YOU die as well. Other than those two mechanics in place, it's the same as before. Nobody seems to realize the Aqua Pura is killing them...

Thanks for the answer. Guess i took the right disision. Found also the con-artist at the entrance of underworld
Alright I am going to continue the game now hehe
thanks for the answer, again

Your character did get a mutation during the wasteland survivor guide if you got a major radiation poisoning so the water would be bad for him.
Ghouls should be hit extra hard from the FEV in the water, luckily the con artist replaced it with standard irradiated water

Actually, you'll die regardles if you "get" a mutation from a quest or perk; you were born in the wasteland, and the FEV kills off anything that wasn't born in a Vault or Enclave bunker.

I forgot about that. I thought because I came from a Vault I'd be fine, but the opening sequence of the game shows otherwise :unsure:
It's a pity, though, that after using the FEV on the purifier the people don't literally start dying. To me it seems as if the population is always still the same. The voice-over at the end mentions the wasteland becoming a graveyard, but it didn't seem like that at all. I suppose it'd be pretty boring if all the towns were empty.