What the Walnut records show
- Water quality and PFAS
- 2 candidate water systems shown.Source date: Violations as of Q1 2026
- Air quality and emissions
- 3 monitoring records shown. Observation year: 2025.Source date: AQS data as of 2026
- Land and cleanup records
- No Superfund records returned in this report; No brownfield records returned in this report.
- Infrastructure and incidents
- 1 pipeline incident record shown; 3 RMP facility records shown (earlier stored inventory, current location coverage unverified).Source date: PHMSA data as of Q1 2026
Water quality in Walnut
Check your water bill for your utility name and confirm the reporting year. See EPA’s guide to finding your annual water quality report.
Drinking Water Compliance
Drinking Water Compliance
Public water-system records for Walnut, CA from EPA SDWIS.
Walnut Park Mutual Water Co.
Active monitoring or reporting issue detected in EPA SDWIS.
Reviewed: active/open records as of Q1 2026
City appears in system name · Serves 16,180 people
Walnut Valley Water District
No active drinking-water issues detected in EPA SDWIS.
Reviewed: active/open records as of Q1 2026
Purchased or imported water record · Serves 100,941 people
Data from EPA SDWIS
Reviewed: source records as of Q1 2026
EPA UCMR5 — No PFAS detection records shown for these water systems
Open data source: EPA UCMR5DoD PFAS — No investigation records shown for this report
Open data source: DoD PFASImpaired Water Bodies
1
Impaired Water Bodies
EPA ATTAINS records identify assessed water bodies that do not meet water-quality standards for designated uses.
Upper San Jose Creek
Reported: Nov 2026
Health-relevant causes: Pathogens
Affected uses: Ecological, Recreation
Data from EPA ATTAINS
Discharge Permits (NPDES)
2
Discharge Permits (NPDES)
NPDES permits regulate pollutant discharges into U.S. waterways. Facilities must report compliance quarterly.
Violation records
Last inspected: Dec 2025
Last inspected: Dec 2025
Data from EPA ECHO
To investigate water contamination, check the sampling locations, dates and results below. For tap water records, see Drinking water quality above.
Reviewed: source records as of 2026
Air quality and emissions in Walnut
Review historical EPA air pollution records, including monitoring and facility emissions where available. For current conditions, check local air quality on AirNow.
EPA AirToxScreen — Estimated Cancer Risk
1
EPA AirToxScreen — Estimated Cancer Risk
Los Angeles County
Assessment year: 2020
According to EPA, a cancer risk of 40-in-1-million means that for every 1 million people continuously exposed to these air toxics over a 70-year lifetime, an estimated 40 may develop cancer from that exposure. This is in addition to cancer risk from all other causes.
Top modeled source groups
Data from EPA AirToxScreen
Nonattainment Status
3
Nonattainment Status
EPA designates an area as nonattainment when air quality does not meet federal health-based standards (NAAQS) for a specific pollutant.
Los Angeles-South Coast Air Basin: Ozone
NonattainmentExtreme8-Hour Ozone (2015 Standard)
Original designation: Aug 2018
Health effects (EPA): Respiratory inflammation, aggravation of asthma, reduced lung function (EPA)
Los Angeles-South Coast Air Basin: PM2.5
NonattainmentSeriousPM-2.5 (2012 Standard)
Original designation: Apr 2015
Health effects (EPA): Cardiovascular disease, respiratory illness, premature death (EPA)
Los Angeles County-South Coast Air Basin: Lead
NonattainmentLead (2008 Standard)
Original designation: Dec 2010
Health effects (EPA): Neurological damage, kidney damage, developmental effects in children (EPA)
Data from EPA Green Book
Air Quality Monitoring (AQS)
Air Quality Monitoring (AQS)
EPA annual monitor summaries describe past measurements. For current air quality, see AirNow.
Anaheim
Annual mean: 0.3 Parts per million
Observation year: 2025
Annual mean: 19.0 Parts per billion
Observation year: 2025
Annual mean: 0.038 Parts per million
Observation year: 2025
Data from EPA AQS
Air Quality Violations or Noncompliance
1
Air Quality Violations or Noncompliance
Facilities regulated under the Clean Air Act. CAA HPV flags indicate serious noncompliance such as exceeding emission limits.
Air Violations
Last inspected: Dec 2025
Data from EPA ECHO
Reported Air Emissions (TRI)
1
Reported Air Emissions (TRI)
TRI releases are self-reported annual totals (calendar year 2024). Hover fugitive or stack for definitions.
Natvar
Reported: 2024
Land cleanup and hazardous waste records in Walnut
Reviewed: source query run Nov 2026
Reviewed: source query run Nov 2026
State Remediation & Cleanup Sites
2
State Remediation & Cleanup Sites
State environmental agencies maintain cleanup site databases that include state Superfund, voluntary cleanup, and brownfield remediation programs. These programs track additional sites beyond those on the federal NPL.
2 sites with active cleanup or investigation
, Walnut
0.8 miles away · LOS ANGELES County
Reported: Nov 2026
, Spadra
0.8 miles away · LOS ANGELES County
Reported: Nov 2026
Data from EPA ECHO
Underground Storage Tanks
Underground Storage Tanks
No release reports shown in this group.
Reviewed: active/open records as of 2018
Data from EPA UST Finder
Reviewed: reporting year 2024
Formerly Used Defense Sites
1
Formerly Used Defense Sites
Formerly Used Defense Sites are properties previously owned by, leased to, or otherwise possessed by the United States and under the jurisdiction of the Secretary of Defense. The FUDS program addresses environmental restoration at these properties.
Open data source: USACE FUDSMSHA Mine and Extraction Sites
MSHA Mine and Extraction Sites
No MSHA mine or extraction site records shown for this report.
County radon potential
1
County radon potential
Los Angeles County, CA
EPA Radon Zone Map (June 2024 release)
Los Angeles County is EPA Radon Zone 2 (moderate potential). EPA defines Zone 2 counties as having predicted average indoor screening levels between 2 pCi/L and 4 pCi/L.
Radon levels can vary from home to home, so EPA recommends testing the property to know its indoor level.
Infrastructure, incidents, and community health in Walnut
FEMA Flood Zones
FEMA Flood Zones
FEMA flood zones describe mapped flood hazards. Look up a specific address with FEMA.
No FEMA flood-zone records shown for this report.
EPA Risk Management Program Records
EPA Risk Management Program Records
Results use an earlier stored RMP inventory. Current EPA ECHO location coverage is unverified.
EPA ECHO lists facilities linked to the Risk Management Program. Results include facilities with locations that can be matched. Records may be historical. Current operations, chemical inventories, and recent accident history are unverified.
Pipeline Incidents
1
Pipeline Incidents
PHMSA tracks incidents involving natural gas and hazardous liquid pipelines. Incidents include leaks, ruptures, and explosions.
Recent Incidents (last 5 years)
SOUTHERN CALIFORNIA GAS CO
Incident date: Oct 13, 2023
- Type
- Gas Distribution
- Cause
- EXCAVATION DAMAGE
- Released
- NATURAL GAS
Property damage: $15,000
Data from PHMSA
Community Health Indicators
Community Health Indicators
Health outcomes from County Health Rankings. Values shown alongside state and national averages.
Los Angeles County, CaliforniaPop. 9,721,138
County Health Rankings edition: 2024
Premature Death
- County
- 6,317
- State
- 6,373
- National
- 7,972
Poor or Fair Health
- County
- 18.2%
- State
- 15.8%
- National
- 14.2%
Poor Physical Health Days
- County
- 3.5
- State
- 3.1
- National
- 3.3
Poor Mental Health Days
- County
- 5.1
- State
- 4.7
- National
- 4.8
Adult Smoking
- County
- 11.0%
- State
- 8.8%
- National
- 15.0%
Adult Obesity
- County
- 28.5%
- State
- 27.8%
- National
- 34.0%
Air Pollution - Particulate Matter
- County
- 13.4
- State
- 7.1
- National
- 7.3
Drinking water violation indicator
- County
- Yes
- State
- N/A
- National
- N/A
Diabetes Prevalence
- County
- 11.7%
- State
- 10.8%
- National
- 9.6%
Life Expectancy
- County
- 80.1
- State
- 79.9
- National
- 77.6
| Indicator | County | State | National |
|---|---|---|---|
| Premature Death | 6,317 | 6,373 | 7,972 |
| Poor or Fair Health | 18.2% | 15.8% | 14.2% |
| Poor Physical Health Days | 3.5 | 3.1 | 3.3 |
| Poor Mental Health Days | 5.1 | 4.7 | 4.8 |
| Adult Smoking | 11.0% | 8.8% | 15.0% |
| Adult Obesity | 28.5% | 27.8% | 34.0% |
| Air Pollution - Particulate Matter | 13.4 | 7.1 | 7.3 |
| Drinking water violation indicator | Yes | N/A | N/A |
| Diabetes Prevalence | 11.7% | 10.8% | 9.6% |
| Life Expectancy | 80.1 | 79.9 | 77.6 |
Environmental questions about Walnut, California
Has PFAS been found in the water in Walnut, California?
This report does not have PFAS sample results for the candidate water systems in Walnut.
Check with the utility that serves your address for its testing results.
What do EPA records say about tap water in Walnut, California?
EPA drinking water records on this page list 3 violations for Walnut Park Mutual Water Co..
The EPA drinking water records available here list no violations for Walnut Valley Water District.
Check your water bill to identify the utility serving your address. Ask that utility about current drinking water advisories.
What do annual air monitors show near Walnut, California?
Nearby EPA monitoring stations provide annual air quality measurements for Walnut.
The monitoring station at Anaheim recorded an annual average of 0.3 Parts per million for carbon monoxide in 2025.
The monitoring station at Anaheim recorded an annual average of 19 Parts per billion for nitrogen dioxide in 2025.
The monitoring station at Anaheim recorded an annual average of 0.038 Parts per million for ozone in 2025.
Download 2025 EPA annual monitor dataCurrent air quality on AirNow
Is there radon in Walnut, California?
The radon data for Walnut covers Los Angeles County. EPA places this area in Zone 2, with a predicted average indoor radon screening level of 2 to 4 picocuries per liter.
Are there Superfund or brownfield sites near Walnut, California?
No Superfund or brownfield sites were returned for this city report.
What is the life expectancy in Walnut, California?
The county data for Walnut reports a life expectancy of 80.1 years in Los Angeles County, California.
The figure is from the 2024 edition of County Health Rankings, a University of Wisconsin program that publishes county health statistics.
What does the data say about premature deaths in Walnut, California?
The county data for Walnut reports 6,317 years of life lost to deaths before age 75 per 100,000 residents in Los Angeles County, California. This measure adds up the years lost to early deaths and adjusts for differences in population age.
The figure is from the 2024 edition of County Health Rankings, a University of Wisconsin program that publishes county health statistics.
Is there air pollution in Walnut, California?
The county data for Walnut lists fine-particle pollution (PM2.5) at 13.4 micrograms per cubic meter in Los Angeles County, California.
The figure is from the 2024 edition of County Health Rankings, a University of Wisconsin program that publishes county health statistics.
What environmental incidents are recorded near Walnut, California?
Federal pipeline records list an incident involving Southern California Gas Co near Walnut on Oct 13, 2023. The reported release was natural gas.