A water shortage that exists entirely on paper is causing problems in the real world.
The Vallecitos Water District, which provides water to 97,000 people in and around San Marcos, told state regulators that demand for water will soon exceed its supplies.
Its projected shortage is 3.7 billion gallons a year by 2020, enough water for tens of thousands of people.
San Marcos residents are alarmed. They fear they’ll be forced to ration water.
The estimates also threaten new development across San Marcos. The Newland Sierra project  – one of the largest housing developments proposed in the county – is facing a lawsuit alleging there isn’t enough water for the 6,000 people expected to live there.
Indeed, a shortage that big could be a major problem. But Vallecitos’ problem might be something else: Its numbers are off.
The numbers came from the district’s 2015 Urban Water Management Plan .
Every five years, every major water agency in California prepares these reports to show they won’t run dry. Of 341 plans  submitted to the state Department of Water Resources, Vallecitos’ plan is the only one to show a major water shortage.
But even the state believes that Vallecitos messed up on the report.
“It looks like they overestimated their demand for some reason,” said Gwen Huff, a senior environmental scientist at the state water resources department.
By overestimating demand, the district created a shortage. (This isn’t Vallecitos only problem of late – its board also has kept water rates so low the district is now selling water at a loss .)
In its plan, Vallecitos assumed that per capita demand in 2020 would be 275 gallons of water per day. That flies in the face of recent history, when average demand has been far less. Last year, per capita demand was 117 gallons per day.
Vellecitos’ senior engineer, Robert Scholl, said the district’s demand projections are based on data from before the drought, when people were using far more water. Other water agencies also calculate “demand” by assuming people will continue to conserve water; Vallecitos’ projections do not make that assumption.
Scholl said in an email that the district is currently “on track” to have more than enough water for everyone, including Newland Sierra.
But assurances like that may not matter – especially not to lawyers – so long as the district’s official Urban Water Management Plan says something else.
“Their own planning documents show they have a shortage,” said Christopher Garrett, an attorney for Golden Door Luxury Spa and Resort in San Marcos.
Golden Door is suing Vallecitos and the developer behind Newland Sierra based on the Urban Water Management Plan. If Newland is built, Golden Door worries it and everyone else in San Marcos will be required to drastically cut their water use.
Golden Door opposes Newland for other reasons, too. Newland would be a sprawling development covering several hundred acres of undeveloped land nearby with 2,100-housing units, an unknown number of businesses and a school. The traffic from Newland alone could wipe out Golden Door’s serenity and drive it out of business, Garrett said.
For Newland to ever be build, its developers must get approval from Vallecitos that there will be enough water for the development. That’s hard to do when the Urban Water Management Plan shows a shortage. Nevertheless, on Oct. 5, Vallecitos’ board approved two documents that said the water agency had enough water for Newland.
Golden Door sued on Oct. 26  to challenge one of them, citing the management plan. To avoid going to court, Vallecitos quickly blinked and last week rescinded its approval  of the document at the request of both Newland and the county, which will also have to approve Newland.
For now, Newland continues to advance with only one of the needed approvals from Vallecitos.
A smaller, 189-home subdivision, the San Marcos Highlands Project, is facing similar questions about water supply, though there’s no lawsuit involved.
An attorney for the Endangered Habitats League, an environmental group, wrote a letter  to the San Marcos City Council earlier this month arguing it should reject the Highlands development because “conclusions regarding adequacy of supplies for the project are unsupported” by Vallecitos’ projections.
The City Council voted to advance the project anyway, but Highlands still faces other votes that could slow it down.
San Marcos Mayor Jim Desmond said he had been assured by Maureen Stapleton, the head of the San Diego County Water Authority, that there was enough water for the county to continue growing for a long time to come. Vallecitos buys most of its water from the Water Authority and then resells it. The Water Authority’s own projections expect San Diegans to be frugal with water  for many years to come.
Ultimately, Vallecitos may need to amend its Urban Water Management Plan. Until then, the document is inviting misunderstanding, alarm and litigation.
Hal Martin, one of the district’s board members, was baffled as he began to grasp the problem during a board meeting last week.
“What is the rationale to make it look like we have a water shortage when we don’t?” he said.