San Diego’s overabundance of water during one of California’s worst droughts has reached a new, absurd level. The San Diego County Water Authority has dumped a half billion gallons of costly drinking water into a lake near Chula Vista.

Now that drinking water has been poured into a lake, the water must be treated a second time before humans can consume it. And here’s another kick in the gut. The drinking water that’s now been dumped into the lake includes desalinated water, some of the most expensive treated water in the world. Water officials will now have to spend even more money to make the once-drinkable desalinated water drinkable once again.

Several factors are causing the bizarre outcome: stubborn water politics, pipeline physics, unexpectedly low demand and the restrictive terms of a contract the County Water Authority signed with water desalination company Poseidon Resources.

The result is that after spending money to make water from Northern California, the Colorado River and the Pacific Ocean drinkable, ratepayers will now have to shell out an additional quarter-million dollars to retreat the water so it’s again fit for human consumption.

“Nobody wants to see any treated water going to a reservoir that would have to treated again,” said Mark Weston, chairman of the County Water Authority’s board of directors.

How This Happened

Several years ago, the County Water Authority imagined an ever-increasing demand for water. So, it embarked on expensive efforts to bring more water into the region, including its backing of Poseidon’s $1 billion desalination plant in Carlsbad.

The County Water Authority did not imagine an extensive drought would prompt Gov. Jerry Brown to order customers across the state to use less water.

As San Diego benefits from its new supplies of water, its customers are cutting their water use.

That means San Diego now has more water than it needs.

About 554 million gallons of treated water has been dumped into the Lower Otay Reservoir, a popular fishing spot near Chula Vista. That’s a very small portion of the County Water Authority’s annual water supplies, but still roughly as much water as 14,000 people use in a year.

Blame Games

There are two types of water. The first is “raw” water that has to be treated before it can be consumed by humans. The second, more expensive kind is water that’s already been treated.

Getting extra raw water isn’t such a big deal, because it’s relatively cheap and can be stored in open air reservoirs and treated later. Regional water officials welcome excess raw water and are storing it in case the drought continues and for emergencies.

But now there’s too much treated water, and that is causing headaches.

The County Water Authority blames its main supplier of water, the Metropolitan Water District of Southern California, for the treated water being dumped into the Lower Otay Reservoir.

In recent weeks, the County Water Authority has asked Metropolitan to stop sending treated water to San Diego from Metropolitan’s treatment plant in Riverside County.

Metropolitan said it cannot do that without making physical changes to its pipeline, which is designed to carry a few hundred gallons per second of water.

“The Water Authority, like, calls us out of the blue and says, ‘We want it lowered to zero,’” said Jeffrey Kightlinger, Metropolitan’s general manager.

Water Authority officials said they did not want all the water Metropolitan sent and are not going to pay for it all.

The same pipelines carry two other kinds of treated water: desalinated water, and water the County Water Authority treated itself at its Twin Oaks Valley Water Treatment Plant in San Marcos.

The water that ended up in the Lower Otay Reservoir is a mixture of these three kinds of treated water.

Of those, the most expensive by far is desalinated water. It costs at least $2,131 for an acre foot, the standard measure used by water officials, which equals 326,000 gallons. Metropolitan’s treated water costs about half that much, $942 per acre foot. The water treated at Twin Oaks costs even less, about $830 per acre foot.

Why is the County Water Authority trying to turn away cheaper water while buying desalinated water? Because it has to buy water from the plant, whether it needs it or not. That’s the deal the authority struck with Poseidon Resources.

“There’s no incentive for Poseidon to shut down and we have to take the water, so this kind of thing, I can see happening more frequently,” said Livia Borak, an attorney who represented environmental groups that opposed construction of the desalination plant.

San Diego water officials said the current situation does not undermine the long-term rationale behind the desalination plant.

“We have built in resources not for this year, next year – but we have built in resources for the next 30 years,” said Weston, the authority’s board chairman.

The authority also expects the desalinated water to become cheaper than Metropolitan’s sometime between 2027 and 2042. The desalination plant is considered a reliable supply for the region, something San Diego can rely on even if there’s an earthquake or if Metropolitan cuts its deliveries, as it did during a prior drought.

“We discovered back in the early-1990s that we really didn’t want to be in that position again,” said Mark Watton, another member of the County Water Authority’s board.

Where This Is Heading

The County Water Authority and Metropolitan are already on bad terms, but officials at both agencies have expressed hope for a quiet resolution to what the authority calls “forced water deliveries.”

The County Water Authority has considered taking Metropolitan to court, although it is working to avoid that outcome because lawyers may cost more than the value of the water at stake.

San Diego officials said they could pay Metropolitan cheaper raw water prices for the treated water. After all, the water can still be used, it just has to be treated again.

“The treatment value is lost, but the water value is still there,” Watton said.

Kightlinger, the Metropolitan head, also expressed interest in a compromise. The compromise proposed by San Diego would cost his agency about $400,000 in lost revenue – which is roughly the value of the treatment done to the water by Metropolitan.

Staff at both agencies are also working on ways to permanently reduce the minimum amount of water that needs to go through the main pipeline involved in the dispute. Any flow below a certain number cannot be read by Metropolitan’s meter.

One solution to all these problems? Just let San Diego use more water.

The County Water Authority has been lobbying against the governor’s water conservation mandate, even though state officials are looking to lock in the water savings so that Californians don’t backpedal and find themselves unprepared for yet another drought.

Last week, the authority sent an 11-page letter to the State Water Resources Control Board that continued to plead San Diego’s case, which is basically that San Diego should have a choice about saving water, in part because it has worked for years to buy itself out of droughts.

“There is no substantial evidence in the record that the Water Authority’s use of water from existing sources is unsustainable, wasteful, or unreasonable because its use will not injure any other water user or the environment,” the letter said. “All evidence is that water is available to the Water Authority and that this water can be used safely and efficiently.”