Need to explain "cropland area displaced by household water consumption"?

Hi, I'm writing a paper and I need to explain what it means here a href="http://myfootprint.org/en/about_the_quiz/faq/" rel="nofollow"http://myfootprint.org/en/about_the_quiz…/a where it says "cropland area displaced by household water consumption" in a paper, and I can't find info on it anywhere. Urgent help is needed