Lack of access to safe drinking water affects communities all over California.

Where Does My Drinking Water Come From?

Your drinking water could come from a domestic well or a water system. Water systems can rely on groundwater or water from streams and rivers (known as surface water), or a combination of these sources.

Let’s figure it out

Enter your address and follow the steps below to learn more about your water. Your information will not be saved and you are welcome to return and enter new addresses.

Step 1. What is your address?

Looking up address.

That address appears to be outside of California.

That address could not be found. Check the spelling and try again.

Calculating water statistics.


According to the information you have provided, your address was found within the service area boundaries of a water system.

If you pay a water bill, your water most likely comes from a water system. If you are a renter and your rent includes water service, your water is also likely from a water system.

Step 2. Click Yes or No to confirm that your water is from a water system.

 


According to the information you have provided, your address was found within an area with domestic wells.

If there is a domestic well on your property or a well that you share with one or more neighbors that you use for drinking water, then your water is likely to be from a domestic well. If you are unsure about whether your water comes from a water system or domestic well, ask your landlord, review the terms of your lease, or review your property details.

Step 2. Click Yes or No to confirm that your water is from a domestic well.

 


According to the information you have provided, your address was found within an area with domestic wells that is also within the service area boundary of a water system.

If there is a domestic well on your property or a well that you share with one or more neighbors that you use for drinking water, then your water is likely to be from a domestic well. If you are unsure about whether your water comes from a water system or domestic well, ask your landlord, review the terms of your lease, or review your property details.

If you pay a water bill, your water most likely comes from a water system. If you are a renter and your rent includes water service, your water is also likely from a water system.  

Step 2. Click either option below to confirm your household water source.

 


According to the information you have provided, your address was found in an area with an unknown water provider.

If you think your water is from a water system, its service area may be either incorrect or missing from the tool. To learn who provides your water, review your most recent water bill, visit the State Board’s water supplier tool or call your County Environmental Health Department. If you think your water is from a domestic well, your household may be in a newer development or is missing from the state’s database of domestic wells.

Step 2. Click either option below to confirm your household water source.

 

Lack of access to safe drinking water affects communities all over California.

Who Manages My Water?

There are several levels of water management in California, from the water system who may supply the drinking water to your home, to the local, regional, and state agencies who regulate water availability and quality in wells and streams. This tool identifies different local agencies that may be making decisions about water in your area.

Water systems are typically overseen by the State’s Division of Drinking Water and typically manage their own water sources. For domestic wells, local agencies will have the authority over any new groundwater well construction or changes to existing wells. Often this will be your County Department of Environmental Health.

Groundwater Sustainability Agencies (GSA) are public entities that manage how groundwater is used locally in certain parts of the state. GSAs have the power to regulate how much groundwater is pumped and by whom. GSAs are developing policies that will impact available supply for both water system wells and domestic wells.

According to the information you provided, your drinking water is supplied from a water system .

Some important jurisdictions in your area include:

  • Water System: [CWS_NAME]
  • Groundwater Sustainability Agency: [GSA_NAME]
  • County: [COUNTY_NAME]

Your representatives:

  • State Assembly: [ASSEMBLYDISTRICT]
  • State Senate: [SENATEDSTRICT]
  • US Congress: [CONGRESSDISTRICT]

* Your address was not found within the boundaries of a Groundwater Sustainability Agency. This means that your area may not be subject to SGMA at this time. Your area might have a voluntary groundwater management plan, contact your county to learn more.

According to the information you provided, you may be served by a domestic well, even though your address was located within the service area of the listed water system.

Some important jurisdictions in your area include:

  • Water System: [CWS_NAME]
  • Groundwater Sustainability Agency: [GSA_NAME]
  • County: [COUNTY_NAME]

Your representatives:

  • State Assembly: [ASSEMBLYDISTRICT]
  • State Senate: [SENATEDSTRICT]
  • US Congress: [CONGRESSDISTRICT]

* Your address was not found within the boundaries of a Groundwater Sustainability Agency. This means that your area may not be subject to SGMA at this time. Your area might have a voluntary groundwater management plan, contact your county to learn more.

According to the information you have provided, your water comes from a domestic well.

Some important jurisdictions in your area include:

  • Water System: [CWS_NAME]
  • Groundwater Sustainability Agency: [GSA_NAME]
  • County: [COUNTY_NAME]

Your representatives:

  • State Assembly: [ASSEMBLYDISTRICT]
  • State Senate: [SENATEDSTRICT]
  • US Congress: [CONGRESSDISTRICT]

* Your address was not found within the boundaries of a Groundwater Sustainability Agency. This means that your area may not be subject to SGMA at this time. Your area might have a voluntary groundwater management plan, contact your county to learn more.

According to the information you provided, your drinking water is supplied from a water system whose boundaries are inaccurate or not currently in our tool. To learn who provides your water, review your most recent water bill, visit the State Board’s water supplier tool or call your County Environmental Health Department. Explore the Map to learn about water systems in your area.

Some important jurisdictions in your area include:

  • Water System: [CWS_NAME]
  • Groundwater Sustainability Agency: [GSA_NAME]
  • County: [COUNTY_NAME]

Your representatives:

  • State Assembly: [ASSEMBLYDISTRICT]
  • State Senate: [SENATEDSTRICT]
  • US Congress: [CONGRESSDISTRICT]

* Your address was not found within the boundaries of a Groundwater Sustainability Agency. This means that your area may not be subject to SGMA at this time. Your area might have a voluntary groundwater management plan, contact your county to learn more.

According to the information you provided, your drinking water is supplied from a water system whose boundaries are inaccurate or not currently in our tool. To learn who provides your water, review your most recent water bill, visit the State Board’s water supplier tool or call your County Environmental Health Department. Explore the Map to learn about water systems in your area.

Some important jurisdictions in your area include:

  • Water System: [CWS_NAME]
  • Groundwater Sustainability Agency: [GSA_NAME]
  • County: [COUNTY_NAME]

Your representatives:

  • State Assembly: [ASSEMBLYDISTRICT]
  • State Senate: [SENATEDSTRICT]
  • US Congress: [CONGRESSDISTRICT]

* Your address was not found within the boundaries of a Groundwater Sustainability Agency. This means that your area may not be subject to SGMA at this time. Your area might have a voluntary groundwater management plan, contact your county to learn more.

According to the information you provided, it looks like your address is in an area with an unknown water provider. If you think your water is from a domestic well, your household may be in a newer development or is missing from the state’s database of completed domestic wells.  Please check back as we will update this tool as new data becomes available.

Some important jurisdictions in your area include:

  • Water System: [CWS_NAME]
  • Groundwater Sustainability Agency: [GSA_NAME]
  • County: [COUNTY_NAME]

Your representatives:

  • State Assembly: [ASSEMBLYDISTRICT]
  • State Senate: [SENATEDSTRICT]
  • US Congress: [CONGRESSDISTRICT]

* Your address was not found within the boundaries of a Groundwater Sustainability Agency. This means that your area may not be subject to SGMA at this time. Your area might have a voluntary groundwater management plan, contact your county to learn more.

This map shows water system boundaries in black. “Explore the Map” to learn more about your area.
This map shows 1-mile square sections shaded by the count of domestic wells, where darker green means a higher count of wells. Water system boundaries are also included in black for reference. “Explore the Map” to learn more about your area.
This map shows 1-mile square sections shaded by the count of domestic wells, where darker green means a higher value. The boundary of a nearby GSA is shown in black. “Explore the Map” to learn more about your area.
This map shows 1-mile square sections shaded by the count of domestic wells, where darker green means a higher value. Water system boundaries are also included in black. “Explore the Map” to learn more about your area.
This map may show water system boundaries. “Explore the Map” to learn more about your area.
This map may show 1-mile square sections shaded by the count of domestic wells, where darker green means a higher value. “Explore the Map” to learn more about your area.

What About Water Supply?

***We are in the process of updating the drought analysis***

While groundwater is a resource that can be replenished, supplies can be threatened. For example, drought, climate change, and high levels of pumping can mean groundwater levels go down, causing drinking water supplies to decrease. Anticipating whether the area where you live could be impacted by future droughts and other drivers of groundwater level change is complicated. One factor that influences possible threats to your water supply is whether your drinking water comes from groundwater and/or surface water. This section can help you learn more about your water supply and whether it could be impacted by changes in groundwater levels, like what often happens during a drought.

The primary water source of a water system indicates the presence of a source type that determines the treatment and filtration requirements for that system. Your water system’s primary water source is [CWS_MAINSOURCE].

Even if your water system’s primary source type is surface water, it could also have access to groundwater.

According to the information you provided, you may be served by a domestic well, even though your address was located within the service area of the listed water system.

The homeowner of a house (or group of homes) reliant on a domestic well is responsible for well maintenance, which includes managing both water quantity and quality.

According to available information, there are [COUNTY_WELLCOUNT] domestic wells in your county.

The homeowner of a house (or group of homes) reliant on a domestic well is responsible for well maintenance, which includes managing both water quantity and quality.

According to available information, there are [COUNTY_WELLCOUNT] domestic wells in your county.

According to the information you provided, your drinking water is supplied from a water system whose boundaries are inaccurate or not currently in our tool. To learn who provides your water, review your most recent water bill, visit the State Water Board’s water supplier tool or call your County Environmental Health Department. Then contact your service provider to learn more about your system’s water supply.

To learn about groundwater in your area Explore the Map.

Your address is in an area with an unknown water provider. According to the information you provided, your drinking water is supplied from a water system whose boundaries are inaccurate or not currently in our tool. To learn who provides your water, review your most recent water bill, visit the State Water Board’s water supplier tool or call your County Environmental Health Department. Then contact your service provider to learn more about your system’s water supply.

To learn about groundwater in your area Explore the Map.

Your address is in an area with an unknown water provider; the tool may be missing water supply information for nearby domestic wells. The homeowner of a house (or group of homes) reliant on a domestic well is responsible for well maintenance, which includes managing both water supply and quality.

According to available information, there are [COUNTY_WELLCOUNT] domestic wells in your county.

To learn about groundwater in your area Explore the Map.


This tool includes an assessment of wells in the Central Valley that could be at risk to supply issues based on different scenarios of drought-related changes in groundwater levels. The analysis includes both domestic wells and public supply wells for small community water systems that serve less than 10,000 people. To learn more about this analysis visit the Methodology. If you are served by a larger community water system and/or live outside of the Central Valley, please contact your water system, Groundwater Sustainability Agency or county with concerns about supply risks in your area.

The drought scenario analysis compares a well’s depth to three estimated groundwater level declines. The three drought scenarios are based on scaling the total groundwater level change observed during the 2012 to 2016 drought. If the groundwater levels in your area dropped 10 feet between 2012-2016, then the 100% drought scenario has 10 feet of decline, the 75% drought scenario has 7.5 feet of decline, and the 50% scenario has 5 feet of decline.  The number of impacted wells in each scenario includes any well that experiences issues because of a drop in groundwater levels including needing to lower the well’s pump, cleaning the well screen to remove sand, or replacing the well if it becomes completely dewatered or dry.


The estimated number of impacted community water system public supply wells within 1-mile of the community water system’s service area for each drought scenario are:

  • [CWS_DROUGHT50_WELLCOUNT] wells in 50% Drought Scenario
  • [CWS_DROUGHT75_WELLCOUNT] wells in 75%  Drought Scenario
  • [CWS_DROUGHT100_WELLCOUNT] wells in 100% Drought Scenario

A zero value indicates that there were no impacts for that scenario. A missing value (·) indicates that there was insufficient data for the analysis. Explore the Map to visualize the estimated costs for each scenario.


The estimated number of impacted domestic wells for your 1-mile squared section, for each drought scenario are:

  • [PLSS_DROUGHT50_WELLCOUNT] wells in 50% Drought Scenario
  • [PLSS_DROUGHT75_WELLCOUNT] wells in 75% Drought Scenario
  • [PLSS_DROUGHT100_WELLCOUNT] wells in 100% Drought Scenario

A zero value indicates that there were no impacts for that scenario. A missing value (·) indicates that there was insufficient data for the analysis. Explore the Map to visualize the estimated costs for each scenario.

This map shows water system boundaries in black and public supply wells locations in blue. “Explore the Map” to learn more about your area.
This map shows water system boundaries in black. If you're served by a water system included in the drought analysis, the system will be shaded by the number of its drought-impacted wells (darker red means higher count). This map also shows public supply wells locations in blue. “Explore the Map” to learn more about your area.
This map shows water system boundaries in black and domestic wells locations in green. “Explore the Map” to learn more about your area.
This map shows water system boundaries in black, and 1-mile square sections shaded by the number of drought-impacted domestic wells (darker red means higher count) for the 100% scenario. “Explore the Map” to learn more about your area.
This map shows the count of domestic wells, where darker green means a higher value at the 1-mile square section level, as well as the boundary of a nearby GSA in black. “Explore the Map” to learn more about your area.
This map shows domestic well areas, where darker color means a higher value at the 1-mile square section level, as well as the boundary of a nearby GSA in black. If there are drought-impacted domestic wells in your area, sections will be shaded by the number of drought-impacted domestic wells (darker orange means higher count and grey indicates that no wells are impacted by drought). “Explore the Map” to learn more about your area.
This map shows the count of domestic wells in your area, where darker green means a higher value. Water system boundaries are also included in black. “Explore the Map” to learn more about your area.
This map shows the count of domestic wells in your area, where darker green means a higher value. Water system boundaries are also included in black. “Explore the Map” to learn more about your area.
This map may show the nearby water system boundaries in black. “Explore the Map” to learn more about your area.
This map shows the count of domestic wells in your area, where darker green means a higher value. Water system boundaries are also included in black. “Explore the Map” to learn more about your area.
This map shows 1-mile square sections shaded by the number of drought-impacted supply wells (darker orange means higher count, and grey indicates no impacts to domestic wells). Nearby GSA boundaries are shown in black. “Explore the Map” to learn more about your area.

What About Water Quality?

The federal Safe Drinking Water Act requires public water systems to regularly monitor for drinking water contaminants to determine if and when they are found above a Maximum Contaminant Level (MCL). If contaminant levels are above and in violation of the MCL- the highest level of a contaminant allowed in drinking water – the water system must notify customers and correct the problem. All water systems monitored by the state are also required to provide an annual water quality report to customers, called a Consumer Confidence Report (CCR).  Domestic wells are not regulated and thus are not required to monitor their water quality. The homeowner of a house (or group of homes) reliant on a domestic well is responsible for testing and treating their own well water.   

This section of the Drinking Water tool can help you learn more about water quality concerns in your area.   This tool currently provides water quality data for four key drinking water contaminants: Arsenic, Nitrate, 123-Trichloropropane, and Chromium VI.  The MCL for each contaminant is shown in milligrams (mg) or micrograms (µg) per liter (L).

The California State Water Board maintains a record of water quality violations in their Safe and Affordable Funding for Equity and Resilience (SAFER) Dashboard. For the most up-to-date information on water system performance measures, search for your water system in the SAFER Dashboard

The contaminant levels displayed for your water system are based on a nine-year average from 2011-2019, for four contaminants (unless your system’s water quality data came from the Monterey County Department of Public Health, see below). The data was developed and shared by CalEPA’s Office of Environmental Health Hazard Assessment for its CalEnviroScreen 4.0 tool.  The contaminant levels for some state small water systems located in Monterey County are the annual maximum measured water quality for each year from 2015-2020, and the overall maximum measured concentration between 2015-2020. The data was accessed from the Monterey County Department of Public Health. 1,2,3-TCP data was not available for Monterey County. 

The data presented in this tool is not necessarily the most up-to-date and may over or underestimate current contaminant concentrations in your water.  To learn more about your system’s water quality, contact your water system and ask for a copy of the most recent Consumer Confidence Report, or search by water system ID in the California Drinking Water Watch website.

Not Detected indicates that contaminant levels were below the detectable limit at which they can be reliably measured, and No Data indicates that the contaminant was not measured in the water system.  The 9-year average estimated value for contaminants found in the groundwater are:

  • [CWS_ARSENIC] Arsenic (As), the MCL is 10μg/L.
  • [CWS_NITRATES] Nitrate as Nitrogen (N), the MCL is 10mg/L.
  • [CWS_TRICHLOROROPANE] 1,2,3-Trichloropropane (1,2,3-TCP), the MCL is 0.005 μg/L.
  • [CWS_CHROMIUM6] Chromium VI (Cr6), the previous MCL is 10 μg/L and California is in the process of establishing a revised one.

Learn more about the data and methods used to estimate groundwater quality for this tool.

This tool has limited information for domestic wells located within the service area of a Water System. Please check back as we will continue to update this tool as new data becomes available. Explore the Map to learn about drinking water quality in your area.

To learn more about domestic well water quality testing, health impacts of drinking water contaminants, point of use treatment options, and available funding to address your water quality concerns, visit Getting Involved.

To get the most accurate source of information on your well water quality, you should test your water. This tool provides estimates of what the groundwater water quality in your area may be, but they are not specific to your well. Instead, the tool provides water quality estimates for four contaminants averaged over 20 years (2001 to 2021) per square mile section. Based on this tool’s analysis, the average estimated value for contaminants found in the groundwater near your domestic well are:

  • [PLSS_ARSENIC] Arsenic (As), the MCL is 10μg/L.
  • [PLSS_NITRATES] Nitrate as Nitrogen (N), the MCL is 10mg/L.
  • [PLSS_TRICHLOROROPANE] 1,2,3-Trichloropropane (1,2,3-TCP), the MCL is 0.005 μg/L.
  • [PLSS_CHROMIUM6] Chromium VI (Cr6), the previous MCL is 10 μg/L and California is in the process of establishing a revised one.

These values are approximations based on water sampling data from untreated public water system well water and from state and federal domestic well sampling projects. Not Detected indicates that contaminant levels were below the detectable limit at which they can be reliably measured, and No Data indicates that no water quality was sampled for this contaminant in your area. Learn more about the data and methods used to estimate groundwater quality in this tool.

The best way to learn about concentrations of contaminants in your own drinking water well is to have your water tested. To learn more about domestic well water quality testing, health impacts of drinking water contaminants, point of use treatment options, and available funding to address your water quality concerns, visit Getting Involved.

Since your drinking water is supplied from a water system whose boundaries are not currently in our tool, we do not have water quality information for your system. In order to learn more about your system’s water quality, ask your service provider for a copy of the most recent Consumer Confidence Report.

To learn about untreated groundwater in your area, browse the domestic well water quality layers Explore the Map.

Since your drinking water is supplied from a water system whose boundaries and thus water quality information are not currently in our tool, in order to learn more about your system’s water quality; determine your service provider, contact them and ask for a copy of the most recent Consumer Confidence Report.

To learn about untreated groundwater in your area, browse the domestic well water quality layers Explore the Map.

Since your address is in an area with an unknown water provider, the tool is missing water quality information for nearby domestic wells. To learn about untreated groundwater in California, browse the domestic well water quality layers Explore the Map.

To learn more about domestic well water quality testing, health impacts of drinking water contaminants, point of use treatment options, and available funding to address your water quality concerns, visit Getting Involved.

This map shows water system boundaries in black, shaded by the estimated concentration of Nitrate as Nitrogen mg/L, where darker orange means higher concentration in relation to the MCL. “Explore the Map” to learn more about your area.
Water quality information is not currently available for your area. “Explore the Map” to learn more about your area.
Estimated groundwater concentration for domestic wells for Nitrate as Nitrogen mg/L, where darker orange means higher concentration in relation to the MCL. “Explore the Map” to learn more about your area.
Water quality information is not currently available for your area. “Explore the Map” to learn more about your area.
Water quality information is not currently available for your area. “Explore the Map” to learn more about your area.
Water quality information is not currently available for your area. “Explore the Map” to learn more about your area.

What About Drinking Water Threats?

Facilities that make, use, store, or treat toxic substances can contaminate groundwater if toxic substances enter the environment and travel to water supplies. While there is no specific distance that is considered “safe” from drinking water threats, drinking-water wells closer to sources of contamination are more likely to become contaminated.

Public supply wells near toxic facilities may be vulnerable to groundwater contamination.  Although water systems routinely test and treat for many contaminants, not all contaminants are currently monitored.

The following potential groundwater threats are located within 5-miles of  one or more of your water system’s supply wells. The presence of one or more threats does not necessarily mean your water is contaminated, and the absence of any threats listed below does not necessarily mean your water is safe.

The following wells supplying your system were sampled for PFAS, and the results were:

  • No PFAS Detected: [PFAS_SAMPLES_CLEAN]
  • PFAS Detected: [PFAS_SAMPLES_DETECTED]
  • PFAS Detected and above MCL: [PFAS_SAMPLES_ABOVEMCL]

Water supplies near toxic facilities may be vulnerable to groundwater contamination.

Explore the map to learn about possible sources of contamination in your area.

 

Water quality from domestic wells is not monitored by state or local authorities. Groundwater near toxic facilities may be particularly vulnerable to contamination.

The following potential contaminant sources were found within 5 miles of your address. The distance to the closest threat of each type is listed below. The presence of one or more threats does not necessarily mean your water is contaminated, and the absence of any threats listed below does not necessarily mean your water is safe.

 

Other threats may exist that are missing from this dataset, ALL wells should be tested for safety

Domestic well testing resources:

Click here to learn about domestic well testing

Click here to find a certified lab that tests for most contaminants

Click here to find a lab that tests for PFAS

Water supplies near toxic facilities may be vulnerable to groundwater contamination.

Explore the map to learn about possible sources of contamination in your area.

Water supplies near toxic facilities may be vulnerable to groundwater contamination.

Explore the map to learn about possible sources of contamination in your area.

Water supplies near toxic facilities may be vulnerable to groundwater contamination.

Explore the map to learn about possible sources of contamination in your area.

This map shows potential drinking water threats near your address. Areas shaded in purple contain possible threats, with darker purple meaning more threats. Any pesticide use in domestic well areas is depicted on the map, which may not represent intensive application. “Explore the Map” to learn more about your area.
This map shows potential drinking water threats near your address. Areas shaded in purple contain possible threats, with darker purple meaning more threats. Any pesticide use in domestic well areas is depicted on the map, which may not represent intensive application. “Explore the Map” to learn more about your area.
This map shows potential drinking water threats near your address. Areas shaded in purple contain possible threats, with darker purple meaning more threats. Any pesticide use in domestic well areas is depicted on the map, which may not represent intensive application. The black circle represents a 5-mile distance from your address. “Explore the Map” to learn more about your area.
This map shows potential drinking water threats near your address. Areas shaded in purple contain possible threats, with darker purple meaning more threats. Any pesticide use in domestic well areas is depicted on the map, which may not represent intensive application. The black circle represents a 5-mile distance from your address. “Explore the Map” to learn more about your area.
This map shows potential drinking water threats near your address. Areas shaded in purple contain possible threats, with darker purple meaning more threats. Any pesticide use in domestic well areas is depicted on the map, which may not represent intensive application. “Explore the Map” to learn more about your area.
This map shows potential drinking water threats near your address. Areas shaded in purple contain possible threats, with darker purple meaning more threats. Any pesticide use in domestic well areas is depicted on the map, which may not represent intensive application. “Explore the Map” to learn more about your area.