Oh in that case I’m sure they would all prefer to die of dehydration instead of drinking slightly contaminated rainwater.

Because it must be equally as bad as all the sewage ground water.

You can distill water with a hole in the ground, a tarp, a coffee can, and a small stone to hold down the center of the tarp.

You can distill your urine this way if it comes to that.

Simply boiling the water is enough to kill most harmful microorganisms that might be in the water.