Think about it. That little boy who's running back into his house, he may have a nice, clean fresh water supply, but he's got dirty hands that he's going to contaminate his water supply with.
Pagalvokite. Tas mažas berniukas, kuris bėgo į savo namus, jis gal ir gali turėti gražų, švarų vandens tiekimą, bet jis turi savo purvinas rankas, kuriomis gali užkrėsti savo vandentiekį.