PFAS water filter Riverside County: military base contamination guide

March Air Reserve Base, located in western Riverside County near the cities of Riverside and Moreno Valley, operated as March Air Force Base from 1918 until its 1996 conversion to a joint-use reserve facility. During that period, military firefighting and crash-rescue training used aqueous film-forming foam, a PFAS-containing suppressant that the Air Force relied on for aircraft fire suppression. AFFF was widely used at Air Force installations from the 1960s onward before the persistent nature of PFAS was fully understood.

The Department of Defense tracks PFAS environmental investigation and cleanup status at active and former installations through its Environmental Cleanup portal at acq.osd.mil/eie/eer/ecc/pfas. March ARB is listed among California military installations where off-base migration of PFAS has been confirmed in groundwater, according to publicly available 2023 DoD PFAS reporting. The California Regional Water Quality Control Board, Santa Ana Region, maintains jurisdiction over environmental monitoring at the site.

Groundwater beneath and around March ARB flows generally southwestward toward the Riverside basin, one of the major groundwater basins in the region. The extent of the plume and its interaction with individual supply wells depends on well depth, pumping rates, and basin-level hydrology documented in ongoing environmental investigation reports, which are publicly available through the State Water Board's GeoTracker database at geotracker.waterboards.ca.gov.

Two sets of enforceable limits now govern PFAS in Riverside County public drinking water. The first is the federal EPA National Primary Drinking Water Regulation for PFAS, published April 10, 2024. That rule sets Maximum Contaminant Levels (MCLs) of 4 parts per trillion (ppt) for PFOA and PFOS individually, and 10 ppt each for PFHxS, PFNA, and HFPO-DA (GenX chemicals). Public water utilities are required to test, report detections, and comply by April 26, 2029.

California has imposed stricter notification levels: 5.1 ppt for PFOA and 6.5 ppt for PFOS, enforced by the Regional Water Quality Control Boards under authority established by Assembly Bill 756 (2020). When a utility detects PFAS at or above a notification level, it is required to notify governing bodies and take corrective action. The California State Water Board PFAS drinking water page at waterboards.ca.gov/drinking_water/certlic/drinkingwater/pfas.html summarizes which systems have been tested, their results, and which have received notifications.

Riverside Public Utilities, which serves the city of Riverside, began PFAS monitoring in March 2019 following a California State Water Resources Control Board order requiring all agencies in the state to test their wells for PFAS over four quarters. Its current PFAS monitoring results and explanatory materials are published at riversideca.gov/utilities/residents/our-water/pfas. Other Riverside County water districts publish their own results through the State Water Board data portal.

Not every filter marketed for PFAS removal performs equally. The key is NSF International certification under a standard that specifically lists PFAS compounds on the product's performance data sheet. You can verify certification for any system at nsf.org/certified-products.

Reverse osmosis systems certified under NSF/ANSI Standard 58 are the most widely documented residential treatment for PFOA and PFOS. The RO membrane physically rejects PFAS molecules based on size and charge, typically reducing PFOA and PFOS by 90 percent or more in independent test protocols. A point-of-use RO system under the kitchen sink addresses drinking and cooking water. For whole-home PFAS reduction from a private well, a point-of-entry RO unit handles all household water before it reaches faucets and appliances.

Granular activated carbon at typical residential flow rates is not reliable as a standalone PFAS treatment. GAC systems can adsorb some PFAS compounds, but performance drops significantly as the filter ages and at the faster flow rates of a whole-home system. If a carbon-based system is used, it should carry NSF/ANSI 53 certification with PFAS specifically listed, and filter replacement schedules must be followed strictly. The EPA PFAS treatment technology page at epa.gov/pfas/pfas-drinking-water-treatment-technologies summarizes the current state of residential and municipal PFAS removal technology.

A water softener does not remove PFAS. Standard cation-exchange resin is designed for calcium and magnesium hardness removal. Many Riverside County homes have both hard water and a PFAS concern, so a softener and a dedicated PFAS filter are often installed together as part of a whole-home filtration system.

Three public tools give Riverside County residents direct access to PFAS monitoring data for their water system:

1. EPA UCMR 5 Data Finder at epa.gov/dwucmr/fifth-unregulated-contaminant-monitoring-rule-data-finder. The Fifth Unregulated Contaminant Monitoring Rule (UCMR 5) required public water systems serving 3,300 or more people to test for 29 PFAS compounds between 2023 and 2025. You can search by state, county, or water system name and download the raw sampling data.
2. California State Water Board GeoTracker PFAS Mapping Tool at geotracker.waterboards.ca.gov. GeoTracker maps PFAS detections by well location across California and links to the underlying sampling data for each site. It also shows DoD investigation sites and their associated groundwater plumes.
3. Riverside Public Utilities PFAS page at riversideca.gov/utilities/residents/our-water/pfas. The city utility publishes its own PFAS monitoring results, regulatory context, and plain-language explanations for customers in the City of Riverside service area.

Your utility's annual Consumer Confidence Report (CCR), mailed or emailed each July, also lists all regulated contaminants detected in the previous year, including PFAS if your system was required to test. The EPA Consumer Confidence Report lookup is at epa.gov/ccr. If your utility serves fewer than 3,300 people or operates a smaller community system, check the California State Water Board PFAS page for smaller-system monitoring results.

Our water checker tool can also help identify contaminants documented for your ZIP code in Riverside County based on publicly available data.

Private wells in Riverside County are not covered by the EPA Safe Drinking Water Act or California public water system regulations. The monitoring, treatment, and safety of private well water are entirely the responsibility of the well owner. This is particularly relevant in Riverside County because areas near March ARB, the Moreno Valley basin, and parts of the Jurupa Valley draw from groundwater that may have connectivity to the documented PFAS plume.

If your private well is within two miles of March Air Reserve Base, or if your property is in a basin where GeoTracker shows PFAS detections in nearby monitoring wells, testing before installing any treatment is the right first step. Request a PFAS panel from a California-certified laboratory. The California Environmental Laboratory Accreditation Program (ELAP) maintains a searchable list of certified labs at waterboards.ca.gov/drinking_water/certlic/labs. A full PFAS panel covering PFOA, PFOS, and the other compounds regulated by the EPA April 2024 rule typically costs $100 to $300 depending on the laboratory and the number of compounds in the analysis (verify current pricing with your selected ELAP-certified lab, as costs vary).

If the test returns PFAS at or above the EPA MCLs (4 ppt for PFOA or PFOS), an NSF/ANSI 58-certified reverse osmosis system at the kitchen sink is the most direct intervention for drinking and cooking water. For whole-home treatment from a private well, a point-of-entry whole-home filtration system sized and certified for PFAS addresses all household water. Retesting after installation verifies removal at the tap.

The Riverside County service area we cover includes Riverside, Corona, Temecula, and surrounding communities. Our technicians assess water test results and recommend specific NSF-certified systems sized to the contamination level and household demand before any purchase decision is made.