> There is a concentration of it where... Unfortunately, lead seems to follow a "anything above 0.000000000000% is harmful, though more is worse" rule. > They

> There is a concentration of it where... Unfortunately, lead seems to follow a "anything above 0.000000000000% is harmful, though more is worse" rule. > They have the ability to... True, but there are a lot of filter-worthy things which can be found in drinking water - https://www.epa.gov/ground-water-and-drinking-water/national-primary-drinking-water-regulations https://www.epa.gov/ground-water-and-drinking-water/national... - so how much filtering, for which contaminants, should they have to do? How often should they have to re-test the (probably municipal) water supply, to verify that their filtering is doing the job? And how much will they mark up the price of water for their tenants, to cover the expenses of all their extra filtering and testing?