Lead and copper summaries

Each row summarises one analyte over one monitoring period for one system. The number of samples behind each value is in the column beside it.

The agency records more than one kind of summary, and the Type column says which. Type 90 is the ninetieth percentile — the value 90% of that period’s samples fall at or below. The agency publishes no explanation for the other codes, so this page does not offer one: a value of another type is not a 90th percentile and must not be read as one.