But it doesn't add up.

Here's an interesting piece I found at http://www.epa.gov/WaterSense/pubs/outdoor.html


"An American family of four can use 400 gallons of water per day, and about 30 percent of that is devoted to outdoor uses. More than half of that outdoor water is used for watering lawns and gardens. Nationwide, landscape irrigation is estimated to account for almost one-third of all residential water use, totaling more than 7 billion gallons per day."
I didn't look into the details, but it's strange that this item would begin with a paragraph where the numbers don't seem make sense: If about 30% of a family's water use is outdoor use, and half of that is for lawns and gardens, one would suppose that about 15% goes to "landscape irrigation," but no, the next sentence says landscape irrigation is almost one-third of all residential water use.

I can't leave this one without pointing out the frequent use of phrases that are possibly very misleading.  The item says that "a family of four can use 400 gallons" per day.  They probably "can" use a lot more than that, but the impression the statement leaves is that they typically do use that much.  If that's what is meant, please be clear about it.  If 400 gallons isn't a fair statement of an average, then the statement can only be regarded as intentionally misleading.  Along the same lines, the item says that "more than half of that .... is used for watering lawns and gardens."   Does that mean "about" half, or is it 90%--which is "more than" half?"  "More than 95%," or "at most $1.50 per day" are probably meaningful, but not "more than half."
The last sentence: "more than 7 billion gallons" has the same problem, and it also has no context: how significant is 7 billion gallons?  It's a nice big number, but I don't know off hand what it means. Is it 0.1 percent of our total water use? or 10%? or 50%? Why say it if you don't explain it?