Will Montecito Run Out of Water?

By Bob Hazard   |   September 21, 2021
The Cachuma Reservoir, MWD’s principal water supply, contains only 51% of its full storage capacity (Photo by Mike Eliason)

As of mid-September, 50 out of the 58 California counties are reporting either “extreme” or “exceptional” drought status. Montecito falls into the “extreme drought” category. While Montecito’s water supply appears secure for the next three years, all bets are off if continued drought becomes the new norm, or if Montecito Water District (MWD) customers are unable to reduce current demand for water by 20% through conservation. 

California’s previous six-year drought, labeled as “the worst drought in 450 years,” began in December 2011 and ended in March 2017. In 2019, California was officially declared drought-free except for a small pocket of “abnormally dry” conditions in Southern California. Sadly, the last two years have brought a new drought threat to Montecito and 88% of the state.

The MWD Board of Directors and its management team have shown commendable foresight in securing an improved water supply portfolio that includes innovative sources of water that are not dependent on unpredictable rainfall; specifically, the Water Supply Agreement with the city of Santa Barbara and a new underground water storage banking program. MWD’s responsibility is “to provide an adequate and reliable supply of high-quality water to the residents of Montecito and Summerland, at the most reasonable cost.”

How Much Water Does MWD Need in a Year?

 MWD has some 4,620 active metered customers in its service area, which includes both Montecito and Summerland. Metered water sales have varied over the last decade.

From 2010 to 2015, in the early years of the last extended drought, water sales for MWD averaged just more than 4,800 acre-feet per year (AFY). From 2015 to 2020, water sales fell to an average of 3,600 AFY with water allocations, mandatory rationing, rationing penalties and the digging of more private wells being credited with the reduction. In the fiscal year ending on June 30, 2021, metered water sales jumped to 4,575 AFY, a 25% increase over the prior year’s use.

Water sales in 2021-22 are forecasted at 3,815 AFY, consistent with the past three-year-average sales, but down from the 2020-21 sales level. MWD urges increased voluntary conservation of 20% in fiscal year 2022, to both reduce demand and to remain in compliance with standards set by the State Water Resources Control Board and the nine California Regional Water Quality Control Boards. Failure to meet these standards can result in MWD’s loss of federal and state loans, grants, and other forms of assistance 

How Will MWD Produce Enough Water to Sell?

In 2021-22, MWD anticipates water production of at least 4,500 AFY. Where will that water come from?

Lake Cachuma Reservoir (50% of Supply)

Lake Cachuma, MWD’s principal water supply, received only minimal inflow during the 2020-2021 winter. Currently, the Cachuma Reservoir contains only 51% of its full storage capacity, or some 98,545 AF. 

Completed in 1953, the Cachuma Project is owned by the U.S. Bureau of Reclamation (USBR). Like other California surface reservoirs, Cachuma’s water supply is subject to major evaporation losses, massive silting that reduces reservoir capacity and environmental releases required for fish protection. Cachuma also suffers from undersized pipes and inadequate intake pump capacity to accommodate the flow of state water and purchased supplemental water into Lake Cachuma.

MWD anticipates receiving some 50% of its water supply needs for the 2021-22 fiscal year but will only know for sure when USBR releases its Cachuma allocations in October.

WSA or Desalination With the City of Santa Barbara: (17% of Supply)

On July 21, 2020, after four years of intense negotiations, MWD signed a 50-year agreement with the city of Santa Barbara for delivery of 1,430 AFY of potable water (or about 35% of MWD’s annual water supply needs), irrespective of rainfall conditions. The agreement was made possible by the city’s renovated desalination facility, which opened in March 2017 at a production capacity of 3,125, roughly one-third of its permitted capacity of 10,000 AFY.

Water deliveries to MWD will begin on January 1, 2022, as do MWD payments of approximately $3,200 per acre foot.

Jameson Reservoir (17%)

District-owned Jameson Lake received less than 200 AF of inflow during the 2020-2021 water year. At the end of July, MWD had some 3,323 AF of water stored in Jameson, only 68% of its current capacity of 4,848 AF. Due to years of silting, the storage capacity of Jameson has been reduced to 70% of its original capacity of nearly 7,000 AF. Environmental restrictions and the cost of trucking dredged silt prohibit economical dredging of Jameson to restore its original capacity. Deliveries from Jameson Lake are projected to provide approximately 17% of MWD’s water supply in 2021-2022.

Doulton Tunnel (5%)

Doulton is a 2.3-mile-long tunnel through the Santa Ynez Mountains connecting Jameson Lake and MWD’s service area. MWD receives tunnel intrusion water (groundwater) along with water delivered from Jameson Lake through the Doulton Tunnel for treatment. 

The intrusion rate has historically varied widely but can range from 1,000 AFY down to the low hundreds. Due to the ongoing severe drought conditions, deliveries from Doulton Tunnel are projected to provide only 5% of MWD’s water supply in 2021-2022.

Montecito Groundwater Basin (11%)

MWD owns a total of 12 active groundwater wells, of which six produce potable water and six produce non-potable water. After reducing pumping since late 2019 to allow for basin recovery, it is anticipated that deliveries from MWD groundwater wells will provide 11% of MWD’s water supply in 2021-22. 

State Water Project (0%)

The California Department of Water Resources has promised MWD an annual allocation of 3,300 AFY of state water, or 73% of the 4,500 AF needed by MWD each year. Unfortunately, promises made are not the same as promises kept.

For the 2020-21 drought year, SWP delivered only 165 AF to MWD, or 5% of its 3,300 AF allocation. This year, SWP delivery is projected to fall to zero because of the lack of snowfall and rain in the High Sierras. MWD, under its SWP agreements, pays the state a fixed payment, regardless of whether it receives no water, or its full allotment of 3,300 AFY.

MWD, through its Joint Power Authority (JPA), paid the state in FY 2020-21 some $7.7 million for conveyance and treatment, representing 47% of MWD’s total expenses of $16.3 million. In return, MWD received only 165 AF of state water. This means MWD and its customers paid a whopping $46,700 per AF for SWP water.

Worse, for the current fiscal year, MWD budgeted another $7.6 million in JPA expense for what is expected to be zero AF of SWP water. Paying a two-year total of $15.4 million to receive 165 AF, or $93,300 per AF, is a tough burden for MWD.

To be fair, SWP does provide a delivery system for water that MWD stores in the Semitropic Water Bank, supplemental purchases of water from agricultural districts or other water sellers, and transfers of water between districts.

Carryover Water 

In addition, MWD has an additional 1,487 AF of carryover water stored in Lake Cachuma, plus another 203 AF of SWP water stored in the San Luis Reservoir in reserve.

Banked Water Supplies 

 The MWD Board and management team have banked an additional 2,000 AF of water in the Semitropic Groundwater Banking & Exchange Program with a right to withdraw up to 1,500 AFY a year. The concept is for MWD to pay Semitropic for the underground storage of excess water deposited in wet years to be withdrawn in drought years as emergency water. 

Purchase Supplemental Water 

In past years, MWD has relied on water purchased by MWD from other districts or agricultural users who have excess water to sell. That water is less available in drought years. Nevertheless, MWD hopes to negotiate a two-year agreement with an agricultural landowner for an option to purchase 2,000 AFY of supplemental water at a cost not to exceed $1,500 per AF. This water would be delivered and stored underground in the Semitropic Groundwater Bank to provide added water insurance.

Could Montecito’s Private Wells Run Dry?

As MWD water prices have risen and calls for conservation have grown louder, larger Montecito users have turned to drilling more and deeper private wells to draw water from Montecito’s limited aquifers. The Groundwater Sustainability Agency (GSA) estimates that there could be some 450 active private wells in the Montecito-Summerland service area, but no one knows for sure the number of wells, or the quality of water, or the flow rates.

The disaster scenario for Montecito would be to have Montecito’s inadequate groundwater aquifers run dry, leaving private well owners without water. If too many straws are inserted into Montecito’s distressed aquifers by private well owners, and the aquifers run dry, or flow rates decline, MWD would be asked to fill the gap. 

Form Montecito GSA

In 2019, MWD formed its Montecito Groundwater Basin Sustainability Agency to comply with the Sustainable Groundwater Management Act, which is intended to ensure that the local groundwater supply is protected from overdrafts. As the new Montecito GSA attempts to determine the number of wells in existence in Montecito and Summerland, as well as their flow rates, they may face opposition from private well owners who fear mandated well restrictions and added charges.

Voluntary Conservation Cut

On August 5, 2021, MWD reported that 75% of its residential single-family customers, which use more than 80% of MWD’s water supply, reported a 25% annual increase in use. In response, MWD called on its customers to voluntarily reduce overall water use by 20%.


There are two ways to solve California’s water problem — increasesupply through affordable technology or decrease demand through conservation. Success will require a combination of both. As deliveries of water from the State Water Project become more unreliable, MWD, its partner agencies and the state need to find environmentally sensitive and affordable ways to produce and deliver reliable water that is not dependent on rainfall. •MJ

Coming Next Week: Part III, The Role of Desalination in an Increasingly Water Scarce World


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