Parched California Farmers Hope to Tap Wastewater From Cities

Will Wong looks over the city of Modesto's new wastewater treatment plant, which could become a water source for local farmers.

Will Wong looks over the city of Modesto's new wastewater treatment plant, which could become a water source for local farmers. (Lauren Sommer/KQED)

Facing record-low water supplies and a dry summer ahead, some California farmers are getting creative in looking for new sources of water. In one community, they’re planning to buy water from cities — after it’s already been used.

Through flushing toilets and running faucets, the city of Modesto produces millions of gallons of wastewater a day, just a stone’s throw from some of the driest agricultural areas in the state.

In a few years, that wastewater — treated and disinfected — could flow to farms in the Del Puerto Water District, in what would be the largest urban-to-agriculture water recycling project in the state.

“It can’t go fast enough,” says Anthea Hansen, who runs the Del Puerto Water District. “Any water would be welcomed at this point.”

The reason is right outside her office window. “This field across the street is about 350 acres,” Hansen says, looking out at bare ground. “This land would typically be farmed in, probably, tomatoes.”

A quarter of the district’s 45,000 acres are fallowed this year, but half of the district is planted in permanent crops, like almonds, that require water every year to stay alive.

“‘Crazy’ wouldn’t adequately describe what we’re going through here,” Hansen says. “Having zero water available, we’ve been in survival and crisis mode for, literally, 24 months now.”

A quarter of farm fields in the Del Puerto Water District are fallowed this year.
A quarter of farm fields in the Del Puerto Water District are fallowed this year. (Lauren Sommer/KQED)

Hansen’s district relies entirely on water from federal reservoirs in the state, through the Central Valley Project. But with record-low snowpack during the drought, that supply has been cut off completely for two years.

The district doesn’t have water rights to local rivers, and lacks groundwater to pump, as many other agricultural areas have turned to doing this year. Buying water on the open market has been Hansen’s only option, but prices have gone through the roof.

Drought-Proof Supply

Even during the drought, around 240,000 Modesto residents produce a steady stream of water — in the form of sewage.

“Water is water,” says Will Wong, engineering division manager for the city of Modesto. “As long as it’s wet, it’s water and it’s valuable.”

The city’s wastewater treatment plant is undergoing a $150 million upgrade to meet new water quality requirements. Currently, most of its wastewater is discharged into the San Joaquin River, and to protect the river, the city is being required to meet higher, “tertiary,” standards.

New filtering equipment is installed at the Modesto wastewater treament plant, part of a $150 million upgrade.
New filtering equipment is being installed at the Modesto wastewater treatment plant, part of a $150 million upgrade. (Lauren Sommer/KQED)

“The nice thing is that we have technology on our side here,” Wong says, “to take water that has some solids and whatnot, and essentially strip everything away and bring back pure water.”

New equipment will filter and disinfect the wastewater with ultraviolet light. It won’t be drinking water quality, but, according to state standards, it’ll be clean enough to use on crops.

In what’s called the North Valley Regional Recycled Water Program, the Del Puerto Water District would construct a six-mile, $100 million pipeline to carry the wastewater from the city to the Delta Mendota Canal. From there, it would go to the district’s farms.

“I really, really, really, truly hope that we can bring it across the line because it will be a model for others,” Hansen says.

The water would be expensive for farmers, four to five times normal prices, but Hansen says that’s the cost of reliability. Growers like Jim Jasper are more than willing to pay.

“When something like this comes up, you don’t have to think about it twice,” says Jasper, who owns Stewart & Jasper Orchards.

“Most farmers are internal optimists and I like to be optimistic,” Jasper says, “but without something like this, the future for my son and grandson and family — we’re into this third generation — I don’t know if we can keep our business going.”

The water would meet about one-third of the water district’s “hardened” demand, or the minimal supply it can get by on. The cities of Turlock and Ceres are also looking at joining the project.

Recycling on the Rise

Other agricultural areas are taking notice, as they face their own drought shortfalls.

“There’s absolutely more potential for recycled water use in California,” says Heather Cooley of the Pacific Institute, a non-profit water think tank in Oakland. According to her analysis, California could be using two to three times more recycled water for many purposes, including urban landscape and golf course irrigation.

Recycling urban wastewater in coastal cities would have added benefits, she says. When wastewater is discharged into the ocean, it creates pollution problems.

But in inland areas, treated wastewater is usually released into rivers, so removing that source of water from the river by recycling it could impact the river itself.

“You need to understand where that water would have gone,” Cooley says. “Is it providing important environmental flows? Is it providing water to a downstream community such that if you’re recycling it, there’s no longer water for that community?”

Challenges From Other Farmers

Two agricultural water districts are protesting the North Valley Regional Recycled Water Program, saying it could harm the area.

Westlands Water District, the largest irrigation district in the country, is challenging the project for its possible effects on the San Joaquin River.

The river is used so heavily by the region that it runs completely dry in some years. As a result, minimal standards have been put in place to ensure enough water is flowing to protect water quality and the endangered salmon that use the river. When those standards aren’t met, water pumping to local irrigation districts must be slowed down.

Wastewater from Modesto and Turlock makes up only a tiny fraction of the overall flow of the San Joaquin River, but Westlands would rather see it go into the river, instead of being recycled, to help meet water quality standards.

A six-mile pipeline would connect Modesto's wastewater treament plant to a canal that reaches Del Puerto Water District's farms.
A six-mile pipeline would connect Modesto’s wastewater treament plant to a canal that reaches Del Puerto Water District’s farms. (Lauren Sommer/KQED)

“In terms of San Joaquin River flow, we are at a point where every acre-foot is important,” Tom Birmingham, General Manager of Westlands Water District, said in an email.

Officials with the Turlock Irrigation District say they’d rather see the wastewater used to replenish local groundwater, and to combat overpumping in the area. The City of Turlock relies on groundwater for its water supply, and after it’s treated, it’s discharged into the San Joaquin River.

“Recycled water is the primary source of water available to help achieve groundwater sustainability,” Calvin Curtin, spokesman for the Turlock Irrigation District, said in an email.

No Silver Bullet

Recycled wastewater projects are currently used in Monterey and Sonoma Counties, where urban areas are close to farm fields. But much of the Central Valley is far from large urban areas, and moving wastewater long distances quickly becomes cost-prohibitive.

“It’s not the single silver bullet solution for agriculture,” Cooley says. “Agriculture is going to have to do a lot of things to adapt to a future of less water availability.”

In the Del Puerto Water District, farmers see water recycling as a way to survive that future. The project still needs a range of permits from local and state authorities, but if it’s approved, the taps could open up in just three years.

  • Watermains

    pipeline, 6 miles for $100,000,000 is $3k/ft, did someone lose a couple of deciemal points?

  • Richard Solomon

    It is no ready made solution. But recycling water can be part of a complex web of interacting parts which lessen the pressure of water needs throughout the state.

    Yes,it’ll cost more money. But then we have to pay for our water use one way or the other.


Lauren Sommer

Lauren is a radio reporter covering environment, water, and energy for KQED Science. As part of her day job, she has scaled Sierra Nevada peaks, run from charging elephant seals, and desperately tried to get her sea legs - all in pursuit of good radio. Her work has appeared on Marketplace, Living on Earth, Science Friday and NPR's Morning Edition and All Things Considered. You can find her on Twitter at @lesommer.

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