I’ve been following it because it is a topic that I’m interested in professionally (my realm of expertise is in safe drinking water.)
Couple of things:
The lead is being leached from the water line fittings, customers’ pipes and faucets because the water is more corrosive than it used to be. The act of switching source water should’ve triggered testing (and it likely did, which is why results exist) to see what the effects were going to be.
Lead and copper sampling are the only samples that water systems do that come from the customers’ tap. [Edited to add: coliform sampling may also be done at a customer’s home but it is more likely to be taken from an outside tap by the water system.] It’s problematic because of that - the water system has no control- the homeowners draw the samples from the tap not the water system. There is a protocol that customers have to follow- letting the water sit for at least six hours. Invalidation criteria is set forth by EPA, but some states will invalidate based on time- like if the customer lets water sit for three hours and then pulls a sample, or if they take it from a faucet that they haven’t used in six months. These are first-draw samples, meaning that the water that first comes out of the tap is what is pulled into the sample bottle. Water systems must use certain home sites, and these sites are used every single round of testing- every three years between June 1 and Sept 30. If a homeowner replaces plumbing then this can mean that the house no longer qualifies as a sample site. Lots of reasons to invalidate sample results but none within the water system’s direct control or knowledge. I say that only because it is a confounding factor to getting good sample results.
The calculation for compliance is the 90th percentile number - so if you have 100 results lined up in order from lowest to highest, sample number 90’s result will be used to determine whether your water system meets or exceeds the action level. As noted above, water systems have from June 1 to Sept 30 to get their preselected residents to take their samples. Not every house will collect their sample at the time they should, so it’s pretty typical for a large water system to turn in sample results in bits and pieces, and the 90th percentile number can’t be calculated until the required number of results is turned in.
A water system may try to invalidate a high sample result. At a minimum, they will take a look at what went wrong if a home they’ve been sampling every three years suddenly gets a huge hit in terms of a result. They’ll go back and talk to the homeowner and find out if the homeowner sampled correctly or not. It should be a huge red flag if a bunch of results come up high.
Pretty much all water systems took out their lead service lines ages ago, so the actual sources of lead aren’t in the water systems’ control (other than adding chemicals to reduce the corrosiveness of the water.). If your house is old enough, you have lead solder in your pipes. Many of the fancier faucets will leach some lead - it has to do with how the faucet metal is cast and coated. Even shut off valves under sinks have been found to be problematic in terms of amount of lead leaching from them.
I don’t know if there was an attempt at a coverup or any wrong doing or not. I don’t have enough info and I’m not the EPA investigator. I can see the moving parts with a certain amount of fear and horror, but I don’t know if it is criminal incompetence or malicious intent. Someone will unwind it (likely the EPA) and blame will be assigned. For now, it should serve as a case study of what not to do when changing water sources. I’m most curious whether the regulating agency considered the effects when approving the new water source.
I live in a water system that has corrosive water. Best practices for homeowners include running the water for several minutes until the water is cold and never using the hot water tap for cooking or drinking (and certainly never installing one of those ‘instant hot’ taps!) It’s the water that has been sitting in the taps the longest that is a problem, not the cold water coming from the street.
Sorry for the long post.