Learn More


Check out this set of useful guides and manuals which contain more information on a variety of topics such as drinking water quality, SGMA policy, well maintenance, and community participation.

Web Resources

Explore additional websites and web tools that are packed with additional resources such as SGMA updates, groundwater glossaries, free “Ask an Expert” services, and other helpful information.

Frequently Asked Questions

All Things Groundwater

The dominant groundwater use in the Solano Subbasin is agriculture, but groundwater is a source of drinking water to the cities of Dixon, Vacaville, and Rio Vista; to rural residential households, churches, schools, and businesses like hotels, marinas, and restaurants, as well as wetlands and creeks.

The easiest way to find out who is using groundwater in your community is by entering your address into the Community Water Center's Drinking Water Tool. This tool gives an in-depth look at your own water profile as well as nearby. The Groundwater Sustainability Plan is also required to include a description of water supplies and which sectors are using those supplies for your basin. This section will include historical, current, and project future water use by each sector in the subbasin.

In the Solano Subbasin, Chapter 4 of the Groundwater Sustainability Plan (Historical, Current, and Projected Water Supplies) will summarize this information. The draft of this chapter should be available by the end of 2020 for public review and comment.

Five Groundwater Sustainability Agencies have joined together as the “Solano Collaborative” to jointly develop one Groundwater Sustainability Plan (GSP) for the entire Subbasin. The Solano Collaborative as a whole is responsible for developing and implementing the management practices that guide your groundwater resources towards sustainability.

Find out who your GSA is by visiting this website and entering your address

The Community Water Center's Drinking Water Tool is a great resource to identify where your water comes from. In fact, this tool provides a wide breadth of information related to your water like:

  • Who manages or makes decisions about your water supply;
  • Groundwater quality in the area where you live;
  • Your water provider and where they draw water from; and,
  • Potential impacts to groundwater supply from future droughts.

If you rely on a community water systems, such as those serving cities, mobile home parks, churches, schools, or food facilities, those systems are required by state law to monitor the quality of the water they supply to the public.


If you rely on a small community water system for your drinking water, and you are interested in finding out the quality of your groundwater: 

  • Contact your water provider and ask for a copy of the most recent Consumer Confidence Report. Public water system providers are required to provide these annually to their customers.
  • Explore The Community Water Center's "Your Drinking Water" Tool to learn more about your water provider and your local water quality


If you rely on a household, domestic well for your drinking water, and you are interested in finding out the quality of your groundwater, take the following actions:


If you have additional questions about the drinking water quality from your well or small community water system, contact your county environmental department:

Sacramento County Environmental Management Department
Environmental Compliance Division
10590 Armstrong Avenue, Suite A
Mather, CA 95655-4153

916-875-8513 (fax)


Solano County Department of Resource Management
Environmental Health Services

675 Texas Street, Suite 5500
Fairfield, CA 94553
(707) 784-6765

In most places around the state, groundwater pumping has not been regulated before the Sustainable Groundwater Management Act passed in 2014.

Landowners could apply for a drilling permit from their county, drill a well on their property, and access groundwater for their needs (agricultural, commercial, drinking water, etc.) without limit. Underneath the surface, groundwater resources are not divided by property lines. We all share the water beneath our feet. Groundwater is critical for meeting our communities' drinking water, agricultural, economic, and ecosystem needs.

Water use activities by a city or individual in one area can impact communities and households located both near and far. For decades, regions throughout the state pumped more groundwater than could be replenished naturally by rain and snow, causing negative impacts for many communities, especially during the drought. Some of these impacts, known as undesirable results in SGMA, include seawater intrusion (when saltwater from the oceans moves inland and enters our freshwater resources stored in underground aquifers), subsidence (when land sinks as a result of overpumping of groundwater), degraded water quality, and the lowering of groundwater levels which has made it difficult, and in some cases, impossible for households with domestic wells to have access to clean drinking water from groundwater. In order to protect this shared groundwater resource, the Sustainable Groundwater Management Act was passed.

Check out this quick overview of California's Groundwater and the Sustainable Groundwater Management Act here.

What goes into the Plan?

A Groundwater Sustainability Plan or GSP, is a plan required by the state for any groundwater basin that the Department of Water Resources identified as at-risk in California.  Plans will guide how groundwater resources are managed in your community with the a 20-year goal of reaching a sustainable balance between community, industrial, agricultural, and environmental needs. Projected climate change impacts and population growth are considered within the plans.

Visit our SGMA 101 page where we break down the basics of what's included in a GSP. Other helpful resources include:

Sustainability reflects the balancing of resource needs of communities, economies, and the environment. The Sustainable Groundwater Management Act (SGMA) is groundwater legislation that requires that groundwater resources remain a reliable and healthy source of water for all those who depend on it. SGMA requires that we consider and protect all uses of groundwater. This includes farms, cities, businesses, tribes, and households that depend on local groundwater, in addition to the creeks, rivers, marshes and wetlands that also rely on groundwater resources. Fundamentally, SGMA is built on the premise that local knowledge and the best available science will create the most effective plan for understanding and managing local groundwater resources for sustainability.

You can help define what sustainability means in your subbasin by weighing in on the Groundwater Sustainability Plan development process. Learn more about ways to contribute here.

Check out this Department of Water Resources factsheet to learn more about sustainability and groundwater resource management.

Models help us understand complex systems, like groundwater basins, so that we can make informed decisions on how to manage those resources. Models help us understand the current conditions of our water resources - both supply and water quality, how those conditions may change over time, and how impactful different actions to manage a resource may be.

Groundwater Sustainability Plans are informed by hydrologic (water resource) models. These models are tools that helpprovide estimates and responses to questions such as:

  • How much water is used annually by each sector of my groundwater community?
  • How much water is available within my groundwater basin? How much water replenishes my groundwater basin each year?
  • How does groundwater use and availability compare in a very wet year versus a very dry year?
  • How might overall water use and water availability change with projected climate change impacts or increases in population growth over time?
  • How might different water conservation programs affect overall water availability? How might different groundwater recharge programs increase overall water availability?

Models work best when informed by good, local data. Hydrologic models are informed by measurements taken throughout the basin on groundwater levels, stream flows, precipitation and weather data, irrigation patterns and other physical data. They are also informed by water use trends over time, and land-use patterns. Models will never be perfect representations of our world, given the complexity of our earth's systems, and the limited data available to help set up a model to reflect local conditions. You can support your local Groundwater Sustainability Agency by providing more information about local conditions through the completion of the Solano Subbasin's survey.

Here are a few more resources to learn more about models:

A water budget, like a household budget, accounts for all the water that enters and leaves your groundwater subbasin. A water budget informs GSAs of the amount of water that can be withdrawn from the subbasin without causing significant and unreasonable undesirable results to groundwater users or the environment. Learn more about water budgets here in this "Getting Involved in Groundwater Guide" (page 13). This SGMA Hydrology factsheet published by the California Farm Bureau also provides a helpful graphic and description of water budgets.

The draft water budget for the Solano Subbasin will be described in Chapter 5: Water Budget of the Groundwater Sustainability Plan. This Chapter will include a discussion of how a water budget for the basin provides an accounting and assessment of the total annual volume of groundwater and surface water (rivers, streams, canals) entering and leaving the basin, including historical, current and projected water budget conditions, and the change in the volume of water stored over time.

If you’d like to be involved, the best way is to fill out the survey, where we are capturing direct feedback from groundwater users like you! Help us understand your interests and concerns related to groundwater quality and quantity.

While there is a lot of data about the Solano Subbasin’s current groundwater conditions, some information is still missing. Your input and knowledge of local water conditions are needed to understand key concerns, and to address gaps of understanding. The objective is to ensure that decisions are both data-driven and well-informed by community members.

Information about local conditions and your experience with site-specific issues is helpful. For example, the technical team is seeking information about:

  • If you have experienced your well going dry 
  • If you have access to well logs for your household
  • If you have access to local groundwater level or quality monitoring data

Information or concerns about specific wells should be directed to

You can also help your local Groundwater Sustainability Agency understand your concerns by answering questions such as "What are the undesirable results we want to avoid in the basin? " or “What are projects or management actions we should consider to meet sustainability goals?Attend local meetings or connect with your local GSA to learn more about opportunities for input.

Be sure to sign up for the newsletter at the Solano Collaborative's website, to receive SGMA 101 overviews, updates, meeting announcements, and invitations to provide public input. Groundwater Sustainability Plan draft sections will be released and posted for public comment here.

How does SGMA affect me?

Groundwater Sustainability Agencies (GSAs) have the power to impose fees on groundwater users to help cover the cost of implementing and monitoring the Groundwater Sustainability Plan. Any fees proposed to be established by a GSA will require a public process before implementation.

Wells pumping less than 2 acre-feet per year (1,785 gallons per day) for household or domestic use are considered to be “de minimis” and could be exempt from most SGMA requirements. This may include exemption from metering, reporting requirements, and fees. Most private, non-agricultural wells will fall into this de minimis category.

Chapter 8 of the Solano Subbasin Groundwater Sustainability Plan will focus on Projects and Management Actions to achieve and maintain basin-scale sustainability. This is the section of the plan that describes the costs, funding, and timelines associated with Projects and Management actions. It will also describe how the Groundwater Sustainability Agencies plan to meet the costs of the Projects and Management Actions. This draft section of the plan will be released in early 2021 for initial public comment.

Groundwater Sustainability Plans are designed to avoid undesirable results caused by changes in groundwater conditions. For example, one undesirable results is the chronic lowering of groundwater levels, which results in a significant and unreasonable depletion of water supply over the planning and implementation period of SGMA (20 years). So what does that mean? SGMA focuses on regional groundwater conditions, over a long-period of time. It should prevent persistent, continuous lowering of groundwater levels over the period of 2022-2042 to meet the goals of the Groundwater Sustainability Plan. SGMA and your local plan may not, however, protect every well against all incidents of wells going dry, particularly during a drought.

There are also proactive actions you can take to better understand local potential drought risk for your well and ways to improve your well's operation and maintenance.

  1. If you have experienced your well going dry, let the Solano Collaborative know by contacting If you have your well construction log available, that will also help the team continue to assess local conditions.
  2. View the Community Water Center Drinking Water Tool and test out different levels of drought scenarios as it pertains to your address and well
  3. Use this Well Owners Manual to learn how to maintain your well and extend its lifespan
  4. Find ways to conserve or reduce your overall water usage.

Monitoring is critical for meeting the subbasin's sustainability goal. Monitoring networks will track groundwater levels regionally over time to identify if, when, and where groundwater levels drop below minimum thresholds. The monitoring network will also track other identified sustainability indicators of undesirable results, such as subsidence (land sinking) or degraded water quality. The projects and management actions implemented to reduce water demand or increase supply will also be assessed to ensure that they are working.

The Groundwater Sustainability Agency is responsible for submitting annual reports to the Department of Water Resources, and for providing 5-year updates to evaluate how well the plan is working to achieve sustainability by 2042.

If you are interested in participating in the monitoring network, the Solano Collaborative is currently looking for voluntary data on groundwater conditions in certain areas within the subbasin. Can you help? This information will give us a better understanding of overall groundwater conditions in the Solano Subbasin. This map shows the areas where we have some data gaps. All personal information will be redacted.

Contact for more information.

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