CNBC's Jane Wells highlights the rise in the business of capturing rainwater in drought-ridden California.

Jane Wells: I know what I want for Christmas. I'm at SOS Survival Products in the Valley with this El Nino coming, people are buying rainwater barrels and not just for residences. Ca Technology, a big company up in the Bay area has spent big on a system to capture water landing on the roof. Won't be potable, but it can be used to offset a huge cost for cooling and for flushing toilets.

Steve Deason: And approximately for every inch of rain that we receive, we can capture about 40,000 gallons, so during a drought year, which is defined as six inches of rain, that's about 240,000 gallons In a normal rainfall year, we would expect to see about 750,000 gallons over the course of a period from December to April.

Jane Wells: Okay. The American Rainwater Catchment Association tells me that the EPA rules are forcing more cities and companies to capture their stormwater, keep it from running into the drain, and bringing pollutants into the system. That's turning an estimated $100 million industry into something a lot bigger.

Brian Quill: We just provided a system for a very large Fortune 500 company that cost about $350,000.

Shad Kazerooni: We've carried 50 products online. Now we carry over 200 products online.

Jane Wells: What's the biggest project you've done so far?

David Crawford, President of ARCSA: Probably a 6 million gallon hospital, a million-gallon system at the Gates Foundation.

Jane Wells: This is $99. Of course guys, it has to rain for the investment to pay off