Table 3.

Mean daily individual probability for infection from drinking contaminated tap water in Norway in 2009.

		Treated drinking water
		Optimal treatment	Excess precipitation
Cryptosporidium	General public	5 × 10−6	3 × 10−5
	Immunocompromised	2 × 10−5	8 × 10−4
Giardia	General public	7 × 10−7	1 × 10−5
	Immunocompromised	0	45 × 10−4