Home » How much percent of impurities are enough to make domestic sewage unfit for humans? Water Pollution MCQs How much percent of impurities are enough to make domestic sewage unfit for humans? September 22, 2022 3 Views Q. How much percent of impurities are enough to make domestic sewage unfit for humans? 0.1 percent1 percent5 percent10 percent Answer: 0.1 percent