San Bernardino sits in one of the most contaminated groundwater basins in California. Between perchlorate from rocket fuel manufacturing, PFAS from military installations, and nitrate from decades of agriculture, the city’s water supply reads like a catalog of industrial-era mistakes.
The Inland Empire isn’t short on water problems. But San Bernardino’s are particularly stubborn — and particularly well-documented.
Perchlorate: The Rocket Fuel Legacy
The biggest contamination story in San Bernardino’s water starts with perchlorate, a chemical compound used in solid rocket propellant. During the Cold War, companies including Lockheed Martin and other defense contractors operated facilities in the region. Perchlorate leaked into the groundwater basin through improper disposal and storage practices.
The Muscoy and Newmark Superfund sites, both in the San Bernardino area, are among the most significant perchlorate contamination zones in the country. The EPA placed these sites on the National Priorities List after perchlorate was detected in multiple municipal wells at levels far exceeding California’s maximum contaminant level of 6 parts per billion (ppb).
San Bernardino Municipal Water Department shut down several wells after perchlorate detections. Some have been retrofitted with ion exchange treatment systems to remove the contaminant, but the cleanup has been slow and expensive.
California set its perchlorate MCL at 6 ppb — far more protective than the federal standard, which the EPA didn’t finalize until 2020 at 56 ppb. That gap tells you something about how seriously the state takes this contaminant.
PFAS: A Newer Problem on Top of an Old One
As if perchlorate weren’t enough, San Bernardino also contends with PFAS contamination. Norton Air Force Base, which operated from 1942 to 1994, used aqueous film-forming foam (AFFF) for firefighting training exercises. AFFF contains PFOS and PFOA — the most studied and most harmful members of the PFAS family.
Norton AFB became a Superfund site after its closure. Groundwater monitoring has detected PFAS in wells surrounding the former base. The contamination plume extends into portions of the city’s drinking water supply.
In 2024, the EPA finalized national drinking water standards for six PFAS compounds, setting enforceable limits of 4 parts per trillion (ppt) for PFOA and PFOS individually. San Bernardino’s water system faces significant compliance challenges given the proximity of PFAS sources to production wells.
The California State Water Resources Control Board has issued notification levels for PFAS that are even more stringent than the federal MCLs, and San Bernardino has been among the systems flagged for elevated detections.
Nitrate: The Agricultural Angle
San Bernardino County was once heavily agricultural — citrus groves, dairy operations, and row crops covered the valley floor. Decades of fertilizer application pushed nitrate deep into the groundwater.
Nitrate contamination in the San Bernardino Basin has forced the closure of several wells over the years. The federal MCL for nitrate is 10 mg/L (as nitrogen), and some wells in the region have tested above that threshold.
For families with infants, nitrate is particularly dangerous. It can cause methemoglobinemia — “blue baby syndrome” — which reduces the blood’s ability to carry oxygen. The San Bernardino Municipal Water Department monitors nitrate levels closely and blends water from multiple sources to keep delivered concentrations within limits.
The Infrastructure Challenge
San Bernardino declared bankruptcy in 2012, and the city’s finances have been recovering slowly since. That fiscal stress has ripple effects on water infrastructure investment. Aging pipes, deferred maintenance on treatment systems, and limited capital for new wells or treatment upgrades are all consequences of a constrained budget.
The city’s water system serves roughly 215,000 people and relies primarily on groundwater from the Bunker Hill Basin. When wells go offline due to contamination, the system loses capacity — and the remaining wells have to work harder.
Water rates in San Bernardino have increased in recent years to fund treatment upgrades and comply with tightening regulations. Residents in lower-income neighborhoods, which make up a significant portion of the city, feel those increases most acutely.
What the Data Shows
According to the EPA’s ECHO database, the San Bernardino Municipal Water Department has maintained compliance with most federal standards in recent years, thanks in part to treatment installations at affected wells. But compliance with new PFAS limits will require additional investment.
The California Division of Drinking Water’s records show the system has dealt with multiple maximum contaminant level violations over the past two decades, primarily related to perchlorate and disinfection byproducts.
EWG’s Tap Water Database identifies several contaminants detected in San Bernardino’s water above health guidelines, including total trihalomethanes, haloacetic acids, chromium (hexavalent), and the contaminants discussed above.
What Residents Can Do
If you’re on San Bernardino municipal water, your provider is treating for the major known contaminants. But treatment at the system level doesn’t eliminate everything, and it doesn’t account for what happens between the treatment plant and your tap.
For perchlorate and PFAS removal, a reverse osmosis system installed at the point of use (typically under the kitchen sink) is the most effective residential option. RO membranes remove both perchlorate and PFAS compounds with high efficiency.
For nitrate, RO is also effective. Standard carbon filters — including popular pitcher filters — don’t remove nitrate or perchlorate.
For lead from older pipes, any home built before 1986 may have lead solder in the plumbing. Running the tap for 30 seconds to two minutes before drinking can reduce lead exposure, and a certified lead-reduction filter adds another layer of protection.
If you’re concerned about your water quality, a certified water treatment professional can test your water and advise on the right solution for your home’s specific situation.
The Bigger Picture
San Bernardino’s water contamination isn’t an accident or bad luck. It’s the predictable result of locating defense manufacturing, military bases, and intensive agriculture on top of a groundwater basin that a quarter-million people depend on for drinking water.
The cleanup is happening — but slowly. Superfund processes move at their own pace, and the responsible parties (including the Department of Defense) have contested liability at multiple points. Meanwhile, the city’s water system has to keep delivering safe water every day.
For residents, the takeaway is straightforward: your water utility is working hard to stay in compliance, but the contamination sources aren’t going away anytime soon. Understanding what’s in your water — and taking steps to protect your household if needed — is a reasonable precaution in a city with this much contamination history.
Sources: EPA ECHO database, EPA Superfund site profiles (Newmark and Muscoy), California State Water Resources Control Board, EWG Tap Water Database, San Bernardino Municipal Water Department consumer confidence reports.