Thirsty? What was derided as ‘toilet-to-tap’ is key to our water future

Many of you have apparently stopped brushing your teeth in the shower. Way to go!

As drought closes in, “water police” patrol many parts of Orange County and conservation is a battle cry, there are some encouraging signs both statewide and locally.

Californians did better at tightening the taps in June: Residential use was down to about where it was in 2019, which was a wet year, and we used 7.6% less water this June than we did in June 2020, new data from the State Water Resources Control Board show.

But don’t get too self-congratulatory. Our cumulative water savings was only 2.7% when looking at the 12 months ending in June compared to the same period in 2020, thanks to a ravenously thirsty spring.

And the (wetter) Bay Area left us in the dust, cutting water use by 12.6% to the South Coast’s 5.9%.

Hey, it’s hotter down here.

We’ll tell you more about how your individual O.C. cities and water districts did in coming days, but in the meantime, there’s this to consider: O.C. is pushing more water in to its vast groundwater basin, and is pumping less water out, as compared to last year.

“That’s, in general, good news,” said John Kennedy, executive director of engineering for the Orange County Water District.

That’s important because this vast groundwater basin is O.C.’s largest source of drinking water.

Vital supply

Managed by the Orange County Water District, the groundwater basin furnishes some 77% of the wet stuff used by more than 2.5 million folks in north and central Orange County. (Sorry, south county folks — you don’t sit atop the aquifer and thus must buy expensive imported water instead. The tyranny of geography!)

But the more-in, less-out story is not entirely one of perfume and roses.

OCWD had to buy imported water to help fill the aquifer, topping off the recycled water it pushes in there (making it cooler than just about every other agency in SoCal, which have lagged in bringing water reuse systems online).

And while some of the decrease in pumping from the aquifer is thanks to conservation, some of it reflects cities shutting off wells that registered contaminants, Kennedy said.

Purify wastewater, drink it

But back to the water reuse/recycling thing. This, the water lords say, is a vital piece of California’s water future, ripe with vast, untapped potential.

Faced with ongoing drought and climate change, California is planning a big push on reuse and recycling over the next few years. Once derisively branded “toilet to tap,” the idea of purifying wastewater from our sewer systems and sending clean water back into the ground to do drinking water duty is now de rigueur.

There’s tremendous room for growth, the State Water Resources Control Board heard at its meeting Tuesday, Aug. 2.

Regulators had hoped to hit 1.5 million acre-feet of recycled water by now — but we’re only at about half of that (732,000 acre-feet).

Still, that’s a nearly 50% increase since the early 2000s, when California logged 525,000 acre-feet of recycled water.

O.C. was hip to this long, long ago.

Pioneers

Visions of the Groundwater Replenishment System began dancing in engineers’ heads a quarter-century ago. Los Angeles and San Diego tried to pursue similar wastewater recycling projects, but the “toilet-to-tap” thing killed them.

O.C., however, stood firm on the logic of it. The system came online in 2008 as a joint project of OCWD and the Orange County Sanitation District, and it’s now touted as the world’s largest advanced water purification system for indirect, drinkable water reuse. (Which is to say, the purified water goes back into the ground to mix with what’s down there before being sucked back up into your kitchen or bathroom or washing machine.)

Right now, the system can produce up to 100 million gallons of high-quality water each day, enough to meet the needs of nearly 850,000 residents. When its expansion project wraps up next year, it will be able to produce up to 130 million gallons per day, enough for 1 million people.

Officials hail it as a locally controlled, drought-proof and reliable supply of high-quality water. On the system’s 10th birthday, it set a Guinness World Records title for the most wastewater recycled to drinking water in 24 hours. And as O.C.’s system celebrates its 14th birthday, others play catch-up.

The giant Metropolitan Water District in Los Angeles is working on a similar project that will eventually dwarf O.C.’s, and the cities of L.A. and San Diego are working on similar projects as well. The idea is to use what we’ve got more wisely.

And on that front, another promising approach was pitched on Tuesday: gray water recycling, the State Water Resources Control Board heard at its meeting.

That simply means capturing water from sinks, showers, dishwashers and washing machines and sending it to yards and gardens to irrigate trees and plants, rather than sending it to the sewer system.

About 1 billion gallons of gray water drain away every day, and capturing gray water could save up to 40% of that, the board was told. The plumbing is easy enough to do in new construction but requires some revamped piping for existing homes

Gray may be the new green! Congrats on deciding to not brush your teeth in the shower. Next assignment: Save the sink water for your petunias.

Source: Orange County Register