Table 1: Copper levels in Nor American household drinking water.

Copper level (ppm)Number of households

Undetectable 0.0180 (28%)12Considered safe
68

0.02114 (41%)36Safety unknown
0.0316
0.0413
0.0515
0.0612
0.077
0.087
0.098

0.181(29%)3Cause Alzheimer’s disease in animal models
0.234
0.314
0.49
0.56
0.62
0.73
0.82
0.92
1.02
1.12
0.21
1.31

1.45 (1.8%)1Above EPA limit
1.81
1.91
3.41
6.01