The four-year drought that has gripped California is adding to the pressure on oil and gas producers in the state to find ways to recycle the billions of gallons of wastewater produced from their wells.

The producers generate over 92 billion gallons of produced water, much of which is brackish and contaminated by traces of petrochemicals and chemicals used for hydraulic fracking. Most of the water is pumped back deep underground, into 50,000 disposal wells.

The shortage of water in California, along with concerns about possible environmental risks associated with the disposal wells, is causing the industry to look at ways to recycle produced water, according to Bloomberg Business.

Conservation is “suddenly leaping to the forefront,” Laura Capper of CAP Resources in Houston told Bloomberg Business. “You’re going to see a lot of retrofit programs. If they’re not already recycling, they’ll be adapting.”

Some companies are experimenting with using pulses of electric current to reduce enough of the salt and other contaminants to make the water acceptable for agricultural irrigation.

Bloomberg reported that Chevron supplied almost 8 billion gallons of treated wastewater to farms last year, and California Resources Corp. (formerly part of Occidental Petroleum) plans to quadruple the volume of water it sells for agricultural use.

Aiming to avoid the use of potable water, Santa Maria Energy LLC, has obtained approval for an $8 million pipeline to bring treated sewage effluent to its wells north of Santa Barbara for use in drilling operations.