Frequently Asked Questions - Mojave Water Agency

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Frequently Asked Questions

Welcome to the Frequently Asked Questions page. If your question isn't answered here, feel free to send us an email.

Development Projects
Mojave Basin Area Adjudication
Mojave River Pipeline
Morongo Basin Pipeline
Mojave Water Agency
Property Taxes
Regional Water Management Plan
State Water Project Water Quality


Q: What is the Mojave Water Agency?

A: The Mojave Water Agency is the guardian of the High Desert’s water supply, ensuring that there is enough water today and for generations to come. Formed in 1960, the Agency is responsible for managing groundwater resources in the Mojave River  Basin and Morongo Basin, and providing alternate water sources to the region as needed. It is one of 29 State Water Project contractors permitted to deliver water from the California Aqueduct. The MWA is also the entity charged with implementing the adjudication,  a court sanctioned groundwater management system designed to gradually bring water used in balance with the available supply.

Q: Why is the Mojave Water Agency needed?
A: Most of the area served by MWA is experiencing severe groundwater overdraft, which means more groundwater is used each year than is replaced by nature through rain and snowmelt. Since 1991, the MWA has been importing water from the California Aqueduct  to recharge the groundwater basins from which local water companies and other well owners derive water for all uses: domestic, agricultural, industrial and recreational.

Q: What is the leadership structure of the MWA?
A: The Agency is governed by an elected Board of Directors responsible for making policy decisions that advance the MWA mission and support its bylaws. The MWA General Manager directs the Agency’s day-to-day operations, implements Board policies  and advises the Board on Agency issues.

Q: Why do we pay taxes to the MWA, if we get our water from a well or a water company?
A: All properties within the MWA’s 4,900 square mile service area benefit from the Agency’s ability to import water from the California Aqueduct. When there is an insufficient amount of local groundwater available, local water companies  and well owners use this imported water for domestic, agriculture and industrial purposes. Taxes paid to the MWA pay the capital cost of facilities required to build the State Water Project and to distribute water to various basins.

Q: Does the MWA have the ability to raise or lower water rates for residents?
No. The Agency may be required to raise wholesale rates to water purveyors in order to cover increases in the State Water Project cost to the Agency or other increases in local costs, like the power to run our facilities. This may cause water purveyors  to raise their rates to cover the additional cost of water purchased from the MWA. But the decision of whether or not to raise water rates to residents is not made by the Agency.

Q: What is the adjudication and how does it work?
The adjudication is a groundwater management system that is an important tool in achieving a long-term, balanced water supply of water for all residents of the Mojave River Basin. The court-sanctioned system grants groundwater rights to users based upon the maximum amount they pumped between 1986 and 1990. Through the stabilizing structure of the adjudication, the long-running condition of overdraft – when more of the local water supply is used than can be naturally replenished – will  be eliminated.

Q: To whom does the adjudication apply?
The adjudication applies to a water user that pumps 10-acre feet or more per year.

Q: What is rampdown?
Rampdown is the primary tool through which the adjudication of the Mojave River Basin is being implemented. It calls for a reduction in pumping rights in five-percent increments until the overdraft is eliminated. Water purveyors can pump more than their share of local groundwater under rampdown, but they must pay an assessment fee on any amount beyond their adjudicated pumping rights. The assessment fee is used to buy imported water to offset the excess local water taken.

Q: What is the Morongo Basin Pipeline and why is it needed?
The Morongo Basin Pipeline is a 71-mile underground pipeline that delivers water from a five-million gallon reservoir in Landers to percolation ponds in the Yucca Valley area. The pipeline serves nearly 60,000 people and 455 square miles of the High  Desert, including the communities of Yucca Valley, Joshua Tree, Landers and Johnson Valley. The pipeline has played and will continue to play a crucial role in bringing water to people, farms and businesses as well as protecting precious groundwater resources.

Q: What is the Mojave River Pipeline and why is it needed?
The Mojave River Pipeline is a 72 mile pipeline designed to replenish natural groundwater supplies in the Mojave River Basin that are threatened by ongoing overdraft. The Mojave River Pipeline, which will run from Duncan and White roads in Adelanto  to Newberry Springs upon full completion, delivers water from the California Aqueduct through the pipeline by gravity flow. The water is then released into recharge basins in or near local riverbeds. The Mojave River Pipeline will deliver up to 45,000  acre-feet of imported water each year to communities in the Mojave River Basin, helping to ensure a stable water supply to area residents.

Q: Why is water conservation important?
With an estimated 60-90% of residential water use in the Mojave Desert region spent on residential landscaping, human use of water is a factor in the region’s ongoing overdraft. Therefore, the increased use of water conservation practices among  High Desert households is the best way for residents to join in the effort to secure a balanced, long-term water supply.

Q: Why is securing a balanced, long-term supply of water so important?
The growth and prosperity of the High Desert depends on a securing a balanced, long-term supply of water. New homes, businesses and schools can’t be built without a stable water supply in place. New state laws SB 221 and SB 610 – which  require that water supply be accounted for before approval of a development project – have been passed in response to growing concern about the continued availability of water to accommodate population growth in California over the next 20 years  and beyond.

Q: What is the Watermaster and how does it relate to MWA?
The Watermaster is a court-appointed accountant for water rights in the Mojave River Basin. The Watermaster’s main responsibilities include monitoring and verifying water production, collecting assessments, conducting studies and preparing an  annual report of its findings and activities to the court. In October of 1992, the Mojave Water Agency was appointed as the initial Watermaster by the Riverside County Superior Court.

Q: What are the sources of the High Desert’s water supply?
The local water source for the High Desert is runoff from the local mountain water sheds. The High Desert has been dependant on groundwater retrieved by wells and by pumping water from groundwater basins and aquifers. The High Desert also receives  water from the State Water Project, which is pumped to our region through the California Aqueduct. Since the MWA is a State Water Project contractor, it is entitled to deliver up to 75,800 feet of water per year from the California Aqueduct.

Q: What are the beneficial uses of our water supply?
Beneficial water uses are many but can generally be divided into municipal, industrial, agricultural, recreational and environmental uses.

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