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Emergency Water Supply

Staff here at Valley of the Moon Water District (District) attempt to maintain high quality water at good, usable, pressure throughout our distribution system at all times. There are times, such as when we experience leaks or planned, new construction that this is not possible. However, those times are usually very short, only lasting a few hours.

Rarely, there can be a major disruption to either our infrastructure or to our main water supplier (Sonoma Water) which can result in a catastrophic drop in water pressure unless drastic action is taken immediately. In order to plan for such an event, the District has sought emergency water supplies in the form of interties with other local public water systems and local ground water production. In these emergencies, we will implement structured plans for notifying customers and ask all water users to reduce water consumption as much as possible. Under these conditions, approved water use will consist only of basic sanitation and drinking water until normal conditions are restored. 

If the condition of our emergency water supply changes, updates will be posted under "News" below.

Where Does Our Water Come From?:

Sonoma Water provides very high-quality water from the Russian River to the District and City of Sonoma (as well as others in Sonoma and Marin Counties) via an aqueduct that runs all the way from Dry Creek, near Lake Sonoma. That water constitutes approximately 80% of the Districts water supply under normal circumstances, with the remaining 20% of our water coming from local ground water wells. 

Other Agency Interties:

The District has two physical interties with neighboring water systems:

  1. A small, mutual water system that occasionally needs assistance in the form of water supply. This is a one-way intertie where the District can supply water to the small system. And

  2. The former Sonoma Developmental Center (SDC). This intertie is no longer active. When it was active, either system could provide water to the other in an emergency.  

The loss of SDC as an emergency water supply drove the District to implement plans for additional/reworked wells to increase our access to sufficient water to meet basic sanitation in an emergency. Plans are in the works currently to establish an intertie with City of Sonoma as well. We will have the ability to share water in both directions in the case of a water supply problem. City of Sonoma and the District both operate local wells that may be useful in this type of emergency.

Local Ground Water:

Currently, the District operates five wells in the southern end of the system. These five wells together, can produce approximately 500 gallons per minute (GPM). The District is implementing a plan to get the number of wells up so we can produce at least 700 GPM,  and future plans to get the District to  900 GPM in order to meet basic sanitation needs in the unlikely event that we lose some or all of our capacity from Sonoma Water.  

Other Action During Water Emergencies

The District has a formal plan to notify the public to a water shortage emergency by alerting publications and internet applications. Further, we have formal procedures to notify all of our high use customers, typically large irrigation and institutional accounts. We can also use our AMI system to monitor the high use customers for compliance.


The District's intertie with SDC was active from 2002 to 2019. After SDC shut down in 2019, the water system stopped operating as well. Before the facilities shut down, SDC operated the only independent, large scale water source in the Sonoma Valley that was not reliant on ground water. The system relied upon two lakes on the campus in conjunction with a surface water treatment plant. The plant was capable of producing 1.8 million gallons per day (or 1,250 GPM) of drinking water. The loss of this source of emergency water puts the residents of the valley at higher risk of source interruption were something to happen to the Sonoma Water source, transmission aqueduct, storage tanks or mainline valves.

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