Chromium-6 in Riverside County: what well water users need to know
Chromium-6 in Riverside County: what well water users need to know
Eastern Riverside County groundwater shows chromium-6 detections. Here is what the data says, who is most at risk, and how NSF-certified filtration protects your household.
State records show chromium-6 in Perris Valley and San Jacinto Basin groundwater. These aquifers supply private wells and some city water in eastern Riverside County. California set its legal limit at 10 ppb in October 2024. But the state public health goal is 0.02 ppb, set because chromium-6 is a probable human carcinogen. That gap is 500 to one. Private well owners face no mandatory testing schedule. Without your own lab results, you do not know your current exposure level. An NSF/ANSI 58-certified reverse osmosis system at the kitchen tap removes 90 to 97 percent of chromium-6 in verified testing. Residents near March Air Reserve Base also face documented PFAS contamination alongside chromium-6 risk. This guide covers the detection data, who is at greatest risk, which treatment technologies are certified, and the specific steps to protect your household.
Chromium-6: a naturally occurring and industrial contaminant
Chromium-6 (hexavalent chromium, Cr-VI) is a form of chromium that dissolves in water. It forms naturally in some rock types. Factories, military sites, and illegal dumping can also release it into groundwater. Once it enters the ground, it moves with the water table and is hard to remove at the source.
Chromium-6 became widely known from the Hinkley, California case. Industrial waste over many years raised chromium-6 levels in local wells there. The Hinkley site is about 60 miles northeast of Perris Valley. The same soil and land-use history that caused the Hinkley problem exist across much of the Inland Empire.
California's health agency (OEHHA) set a Public Health Goal of 0.02 ppb for chromium-6. OEHHA considers that level to pose very low cancer risk over a lifetime (source: oehha.ca.gov). The legal limit (MCL), set in October 2024, is 10 ppb (source: waterboards.ca.gov). Your water can meet the legal limit and still be far above the health goal.
Perris Valley, San Jacinto Basin, and eastern Riverside County
Eastern Riverside County has several connected groundwater basins. Homeowners and farmers have drawn water from these basins for years. State monitoring shows chromium-6 above the Public Health Goal in both the Perris Valley Basin and the San Jacinto Basin.
The SWRCB Drinking Water Watch database (waterboards.ca.gov/drinking_water/certlic/drinkingwater/DWW) lets you look up your water system's results. If you are on a private well, these rules do not cover you. You need to arrange your own testing.
Cities like Riverside, Corona, and Temecula blend groundwater with imported water. This often lowers chromium-6 levels. But the blend changes by season. Some wells in the network may carry higher levels than the blended average in your annual water report.
March Air Reserve Base near Perris has pollution from past military and industrial work. Records show both PFAS compounds and chromium from base operations. Cleanup and monitoring programs are ongoing. But the pollution has reached nearby groundwater that private wells draw from.
If you own a private well within a few miles of the base, test for both PFAS and chromium-6. Do not rely only on city water reports. Those cover only regulated water systems.
Who faces the highest chromium-6 exposure in Riverside County
No required testing. No annual water report. Without your own lab test, you have no way to know your exposure. This is the highest-risk group in eastern Riverside County.
The documented chromium and PFAS pollution means risk is compounded here. Test for both contaminants.
State records show chromium-6 in these basins. If you are on a small water system, review your latest annual water report.
Blended supplies tend to show lower levels. But many ZIP codes still exceed the OEHHA health goal of 0.02 ppb. Review your annual water report.
California's MCL vs. the Public Health Goal: why the gap matters
California has two standards for chromium-6. The legal limit (MCL) is what utilities must stay below. As of October 2024, that limit is 10 ppb. A water system that meets the MCL is following the law.
The Public Health Goal of 0.02 ppb is the level OEHHA links to very low lifetime cancer risk. A water supply reading 0.3 ppb, which is common in parts of Riverside County, meets the legal limit. But it is 15 times higher than the health goal.
If you want your drinking water near the health goal, a home filter is your best option. City utilities only have to meet the legal limit. An NSF-certified RO system at your kitchen tap can bring your drinking water close to that goal.
| Standard | Level | What it means | Source |
|---|---|---|---|
| California MCL | 10 ppb | Legal limit for regulated utilities. Re-established October 2024. | waterboards.ca.gov |
| California PHG (OEHHA) | 0.02 ppb | Science-based very-low-risk level for lifetime exposure. | oehha.ca.gov |
What actually removes chromium-6 from Riverside County water
Most filters do not work on chromium-6. You need a system certified to NSF/ANSI for chromium-6 removal. The NSF registry at info.nsf.org/Certified/DWTU lists certified products. For chromium-6, look for NSF/ANSI 58 (under-sink RO) or NSF/ANSI 61 (whole-home systems).
| Technology | Chromium-6 removal | Coverage | Notes |
|---|---|---|---|
| Under-sink RO (NSF/ANSI 58) | 90-97% | Drinking + cooking tap | Most practical point-of-use option |
| Whole-home strong-base anion exchange (NSF/ANSI 61) | 85-95% | All household water | Higher upfront cost; requires regeneration |
| Whole-home RO | 90-97% | All household water | High water cost; large footprint |
| Carbon block pitcher or faucet | Not rated | Drinking only | NOT effective for chromium-6 |
Always check a system's NSF certification number on the official registry before buying. Marketing claims without a listed number are not verified.
How to check your Riverside County water right now
- 1Look up your utility on SWRCB Drinking Water Watch
Visit waterboards.ca.gov and search by ZIP code or system name. Review the most recent chromium-6 results. If your system does not appear, you are likely on a private well and need to test on your own.
- 2Read your annual water report
Your utility sends or posts this each year. Look for chromium-6 (sometimes listed as hexavalent chromium) and compare the highest detected level to the MCL (10 ppb) and the health goal (0.02 ppb).
- 3Test your well if you are on a private system
Contact your Riverside County Environmental Health office for a list of certified labs. A basic chromium-6 test costs less than a filter consultation. It is the only way to know your actual exposure.
- 4Get a professional water assessment
A licensed technician tests your water for chromium-6, PFAS, arsenic, and hardness. Use the results to choose the right system for your home.
Frequently asked questions about chromium-6 in Riverside County
Yes. State records show chromium-6 in Perris Valley and San Jacinto Basin groundwater. Levels vary by utility and by well. City supplies that mix groundwater with imported water often have lower amounts than private wells. Check your utility's annual water report, or use the SWRCB Drinking Water Watch tool at waterboards.ca.gov/drinking_water/certlic/drinkingwater/DWW to find your system's results.
California set a Maximum Contaminant Level (MCL) for chromium-6 at 10 parts per billion (ppb) in October 2024 (source: waterboards.ca.gov/drinking_water/certlic/drinkingwater/Chromium6.html). The California Public Health Goal (PHG), set by OEHHA, is 0.02 ppb. OEHHA considers that level to pose very low health risk over a lifetime (source: oehha.ca.gov/water/public-health-goal/chromium-vi-drinking-water). Water can meet the legal MCL and still be far above the health goal.
Yes. Private well owners are not covered by public utility monitoring rules. So chromium-6 can go undetected without your own testing. The Perris Valley area and communities near March Air Reserve Base have recorded pollution from past industrial and military use. The SWRCB Drinking Water Watch database covers regulated utilities, not private wells. Periodic lab testing is the only way to know your well's current levels.
March Air Reserve Base near Perris has recorded PFAS and chromium pollution from past operations. Cleanup and monitoring programs are ongoing. But the pollution has spread into nearby groundwater basins used by private well owners. If you own a well near the base, test for both PFAS and chromium-6. Do not rely on city utility reports. Those cover only regulated water systems.
Reverse osmosis (RO) systems certified to NSF/ANSI Standard 58 are the most practical option. These remove 90 to 97 percent of chromium-6 in testing. Under-sink RO units treat your tap water for drinking and cooking. Whole-home strong-base anion exchange systems certified to NSF/ANSI 61 work at the whole-house level. Carbon block and pitcher filters do not remove chromium-6. Check any system's NSF certification at info.nsf.org/Certified/DWTU before buying.
Start with the SWRCB Drinking Water Watch portal at waterboards.ca.gov/drinking_water/certlic/drinkingwater/DWW. Enter your water system name or ZIP code to find results for regulated utilities. If you are on a private well, contact a California-certified lab. Your county health office can provide a list of certified labs.
More chromium-6 and water quality resources
The full picture across all SoCal counties, utility sources, and treatment options.
A technology comparison guide for buyers: RO, anion exchange, and what to avoid.
The San Gabriel Valley Superfund site and what LA County residents need to know.
San Diego water sources, detection levels, and treatment options for North County well users.
Military base plumes, municipal supply detections, and combined PFAS and chromium-6 treatment.
Professional installation of NSF-certified chromium-6 filtration systems across SoCal.
Under-sink and whole-home RO installation by licensed technicians.
What chromium-6 is, how it gets into water, and what certified filters remove it.
Water treatment service covering Riverside, Corona, Temecula, Moreno Valley, and surrounding areas.
Enter your ZIP to see what contaminants have been detected in your area.
PFAS detection data near March ARB and Inland Empire communities, and how to filter both PFAS and chromium-6.
County-by-county contaminant summary for chromium-6, PFAS, arsenic, nitrates, and hardness.
Arsenic occurs naturally in Inland Empire groundwater. What certified RO systems remove and what to test for.
Agricultural runoff and naturally occurring nitrates in the Inland Empire and what filtration addresses them.
Lead from older plumbing and service lines. NSF/ANSI 58 RO systems address both lead and chromium-6.
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