Lead in West Virginia school drinking water

The source publishes one row per sample taken at a fixture, so every figure below counts fixture samples. A sample is counted above the action level here when its measured value is at or above 15 ppb.

Samples collected

1,240

Readings published

1,240 — every one carrying a number. West Virginia does not mark a reading its laboratory could not measure, so how many of these are measurements and how many are non-detects recorded at a reporting limit is not derivable from what it publishes.

1,240 readings published = 1,240 samples collected

West Virginia's readings sit on two floors rather than one. Every reading collected before July 2022 — 383 of 1,240 — is 1 ppb or above, 247 of them exactly 1. From November 2022 the lowest reading is 0.4 ppb, with 351 at exactly that value and 205 falling between the two. That is consistent with non-detects being recorded at a laboratory reporting limit that changed during the programme rather than flagged as non-detects. None of the state's four published programme documents states a limit, so we do not state one, we do not say which readings are non-detects, and we do not compute a measured-only rate for West Virginia. That inference is ours, not the state's. The share of all samples collected at or above the action level is not affected by it.

2.9% (36 of 1,240 samples collected) — fixtures at or above 15 ppb, the state's action level

18.1% (19 of 105 schools with published results) — schools at or above 15 ppb, the state's action level

The two rates above count fixture samples; this one counts schools with at least one sample at or above the level. The gap between them is itself informative, and the two units must never be mixed inside one comparison.

Sampling period: 2021-11-23 to 2024-09-24.