NEW YORK (TheStreet) -- California policymakers and industry executives gathered in San Francisco last week at the Economic Power of Water conference to discuss ways to mitigate that state's severe drought, including new investments in technology. The conference, sponsored by General Electric (GE) - Get Report and the University of Pennsylvania's Wharton School of Business, took place Wednesday, just days after new mandatory water-use restrictions went into effect in California. Executives from GE, Intel (INTC) - Get Report, and Pacific Gas & Electric (PCG) - Get Report talked about the efforts being made by their companies. 

"We think the situation here in California specifically calls for more investments in wastewater treatment plants that can recycle and reuse water and make it available for agriculture, for aquifer recharge," said Heiner Markhoff, president and CEO of GE Water & Process Technologies

Orange County recently made a big investment in expanding a wastewater treatment plant that has been operational since 2008. The plant added extra capacity just this month.

"Our facility itself produces 100 million gallons, and in fact, the plant is the largest indirect potable reuse project in the world," said Mike Markus, general manager of the Orange County Water District. "What we're seeing in California is more and more agencies are looking at this type of project to increase their water supply." 

Wastewater recycling -- also known by the unpopular and polarizing phrase "toilet-to-tap" -- isn't the only solution, however. There's a lot of excitement around a new desalination plant going on line later this year in San Diego County, one billed as the largest seawater desalination plant in the Western Hemisphere. The project was financed by a private company, Poseidon Water. Industry experts say more public-private partnerships like that one are needed to help pay for new water projects.

"Anything that allows us to attract more capital to this problem is highly valuable," said Robin Gilthorpe, CEO of WaterSmart Software. "The investment gap for water infrastructure in the U.S. is $1 trillion. Nobody's going to write that check."