Cr-6 in LA Water 2026: LADWP + Met Customer Guide

Chromium-6 (Cr-VI, hexavalent chromium) is a California-specific drinking water concern. California sets a notification level of 0.02 ppb for Cr-VI, while the federal EPA has no MCL specifically for Cr-VI (only a total chromium standard of 100 ppb). The San Fernando Valley contains documented Cr-VI groundwater plumes (Burbank and Glendale Operable Units, both EPA Superfund sites) with active pump-and-treat remediation. LADWP reports Cr-VI in its annual Consumer Confidence Report. An NSF/ANSI 58 certified reverse osmosis system reduces chromium to below 0.005 ppb in typical residential testing.

What Chromium-6 Is and Why California Regulates It Harder

Chromium occurs in two main valence states in water. Chromium-3 (trivalent) is an essential trace nutrient and is poorly absorbed. Chromium-6 (hexavalent, written Cr-VI or Cr(VI)) is the toxic form. It is classified by the EPA as "likely carcinogenic to humans" by oral exposure and "known human carcinogen" by inhalation. The US National Toxicology Program lists Cr-VI as a known carcinogen.

The federal Safe Drinking Water Act sets a Maximum Contaminant Level (MCL) of 100 ppb for total chromium (Cr-3 plus Cr-6 combined). The federal government has never set a separate MCL for Cr-VI alone. California, by contrast, has treated Cr-VI as a distinct regulatory target since the 1990s. The California State Water Resources Control Board (SWRCB) currently uses a notification level of 0.02 ppb for Cr-VI in drinking water, which is the lowest level routinely quantifiable in standard lab testing.

Why the difference? California has more documented Cr-VI contamination than any other state, the largest body of public health research on the contaminant, and a regulatory mandate (Health and Safety Code section 116365.5) that specifically directed the state to set an MCL for Cr-VI. California voters and legislators have treated Cr-VI seriously since the Hinkley case became public in the mid-1990s.

California Chromium-6 Regulatory History

The story is messy. Here is the verified sequence.

• 1991: California Public Health Goal (PHG) for total chromium set at 2.5 ppb.
• 1993: Erin Brockovich and the Masry law firm begin investigating Cr-VI groundwater contamination in Hinkley, California (San Bernardino County), traced to a PG&E natural gas compressor station that used Cr-VI as a corrosion inhibitor from 1952 to 1966.
• 1996: PG&E settles the Hinkley case for $333 million, the largest direct-action settlement in US history at the time. The case enters public consciousness through the 2000 film "Erin Brockovich."
• 2001: California legislature passes SB 351 directing the state to set a Cr-VI specific MCL.
• 2011: California sets a Public Health Goal of 0.02 ppb for Cr-VI based on a 1-in-1-million lifetime cancer risk.
• 2014: California Department of Public Health adopts the first state-level MCL for Cr-VI at 10 ppb, effective July 2014. It was the first such standard in the United States.
• 2017: A California Superior Court overturns the 10 ppb MCL after a lawsuit by the California Manufacturers and Technology Association, ruling that the state failed to adequately consider economic feasibility. The MCL is withdrawn.
• 2024: California SWRCB initiates new rulemaking to re-adopt a Cr-VI MCL, this time with a formal economic feasibility analysis. The 0.02 ppb notification level remains in effect during the rulemaking.

So as of 2026, California operates under a notification level of 0.02 ppb (utilities must notify the state when they exceed it) while the formal MCL is in renewed rulemaking. The federal floor (100 ppb total chromium) still applies, but California utilities report Cr-VI separately.

The San Fernando Valley Cr-VI Plume

This is the most important part of the LA-specific story, and most LADWP customers have never heard of it. The San Fernando Valley sits on top of one of the largest documented industrial groundwater contamination zones in the United States, with two EPA Superfund sites specifically tied to Cr-VI and related solvents.

Burbank Operable Unit (Burbank OU): EPA-designated Superfund site covering roughly 4 square miles of the eastern San Fernando Valley underneath Burbank. Historical aerospace, metal plating, and industrial operations (Lockheed plants among them) discharged Cr-VI, trichloroethylene (TCE), and perchloroethylene (PCE) into the aquifer beginning in the 1940s. EPA ordered remediation in the early 1990s. Active pump-and-treat groundwater extraction has been running for over two decades, with ongoing monitoring.

Glendale Operable Unit (Glendale North and South OUs): Adjacent Superfund site covering portions of Glendale. Similar contamination history (aerospace, plating, dry cleaning solvents). EPA-ordered remediation began in the mid-1990s. The Glendale Water and Power utility operates treatment plants that strip Cr-VI and VOCs from extracted groundwater before delivering it to ratepayers or returning it to the basin.

Why this matters for LA tap water: LADWP historically drew about 10 to 15 percent of its supply from San Fernando Valley groundwater wells. When the Cr-VI and solvent contamination was documented in the 1980s, LADWP took most of those wells offline. Burbank and Glendale, which depend more heavily on local groundwater, built dedicated treatment plants to remove Cr-VI before delivery.

The plume is not gone. EPA documentation shows pump-and-treat operations are projected to continue for decades. Residents living over or immediately downgradient of the Burbank or Glendale OUs, especially anyone on a private well rather than municipal water, have a documented Cr-VI exposure risk that residents in West LA or the South Bay do not.

LADWP vs Metropolitan Water District vs Local LA Utilities

Different LA-area utilities pull from different sources, and Cr-VI exposure varies accordingly.

• LADWP (Los Angeles Department of Water and Power): Roughly 50 percent of supply comes from the Los Angeles Aqueduct (Owens Valley, Eastern Sierra). Owens Valley source water has low natural Cr-VI. About 35 to 40 percent comes from Metropolitan Water District purchases (Colorado River and State Water Project). The remaining 10 to 15 percent is local groundwater, with most San Fernando Valley wells either treated or offline due to the OU plumes. LADWP reports Cr-VI annually in its CCR.
• Metropolitan Water District (Met, MWD): The wholesale supplier to 26 member agencies across six counties. Met pulls from the Colorado River (via the Colorado River Aqueduct) and the State Water Project (Sacramento-San Joaquin Delta). Colorado River water carries trace naturally occurring Cr-VI from chromium-bearing geology. Delta water is typically lower. Met treats but does not specifically remove Cr-VI at most plants.
• Burbank Water and Power and Glendale Water and Power: Both operate local groundwater treatment specifically engineered to remove Cr-VI before delivery, as part of the Superfund remediation agreements. Treated water meets the federal 100 ppb total chromium standard with substantial margin.
• Smaller LA utilities and private wells: Foothill, Crescenta Valley, La Cañada, and several San Fernando Valley mutual water companies have varying Cr-VI profiles depending on well location relative to the OUs. Private well owners in the SFV should test specifically for Cr-VI.

If you want to know your specific exposure, the LADWP and Met annual water quality reports publish Cr-VI averages and ranges. The California SWRCB Cr-VI page publishes current notification level data.

Home Filtration Options That Remove Cr-VI

Not all water filters remove chromium-6. This is one of the most misunderstood points in residential water treatment. Here is what actually works.

Reverse osmosis (RO), NSF/ANSI 58 certified: RO is the residential gold standard for Cr-VI removal. The semi-permeable membrane rejects dissolved ionic species including chromate. Properly maintained, an under-sink RO system reduces Cr-VI from typical LA tap concentrations (around 0.1 to 0.3 ppb) to below the 0.005 ppb detection threshold in routine post-installation testing. NSF/ANSI 58 is the standard for RO systems; the P473 endorsement under that standard adds PFAS reduction (and the same mechanism handles Cr-VI well).

Strong-base anion exchange (specialty resin): Removes 90 to 95 percent of Cr-VI. Used at the utility scale by Glendale Water and Power. Available as a residential point-of-entry system but requires specialty resin certified for chromium and periodic regeneration with brine.

Activated carbon (block or granular): Does NOT remove dissolved Cr-VI reliably. Removes less than 30 percent in independent testing. Carbon is the right tool for chlorine, chloramines, VOCs, taste, and odor, but not for Cr-VI.

Ion exchange water softener (sodium-cycle): Does NOT remove Cr-VI. A softener removes calcium and magnesium hardness ions only; chromate ions pass through. Owning a softener or salt-free conditioner provides zero Cr-VI protection.

Boiling: Does NOT remove Cr-VI. Evaporation actually concentrates dissolved metals in the remaining water.

Recommended Method by Water Source

Your Water Source / Cr-VI Exposure	Recommended Filtration	Typical Install + 10-Year ROI
LADWP, no SFV groundwater concern	Under-sink NSF/ANSI 58 RO at kitchen tap	$1,800-$2,800 install; saves $4,000-$8,000 vs bottled water over 10 years
Met-supplied utility (Colorado River blend)	Under-sink RO plus whole-house carbon for chloramines	$2,500-$3,800 install; eliminates bottled water plus extends appliance life
Burbank or Glendale municipal water	Under-sink RO at kitchen (treated supply is already Cr-VI compliant, RO is redundancy)	$1,800-$2,800 install; peace of mind plus PFAS and lead reduction
Private well in San Fernando Valley near Burbank or Glendale OU	Whole-house anion exchange OR whole-house RO plus annual lab testing	$6,000-$12,000 install; only verified path to safe drinking and bathing water
LA home with dialysis patient or infant formula prep	Under-sink RO certified to NSF/ANSI 58 P473 with annual filter service	$2,000-$3,200 install plus $150-$250 per year service

Call a Professional If

• You live on a private well within two miles of the Burbank or Glendale Operable Units. Cr-VI plume monitoring shows ongoing groundwater contamination; municipal treatment does not apply to private wells. Annual Cr-VI lab testing is non-negotiable.
• A household member is on dialysis. Dialysis patients are exposed to roughly 300 liters of water per treatment session through the dialysate. Even trace Cr-VI is amplified. Dialysis-grade RO is the standard of care.
• You have a child under one year old or you are pregnant. Infant formula reconstituted with tap water and developing fetuses are the most sensitive populations for any metal contaminant. NSF/ANSI 58 RO at the kitchen tap is the responsible default.
• Your latest LADWP, Burbank, or Glendale CCR shows multiple contaminants near or above health-based goals. Cr-VI plus PFAS plus disinfection byproducts is a combined load that warrants whole-house plus point-of-use treatment.
• You have unexplained skin irritation, persistent metallic taste, or yellow-green staining on fixtures, especially in older homes with copper or galvanized plumbing.
• You have had a recent home water test return Cr-VI above 0.02 ppb. This is the state notification threshold. Treatment is warranted regardless of whether the federal MCL has been exceeded.
• You are buying a home in the San Fernando Valley. A pre-purchase water panel including Cr-VI, VOCs, and total chromium is a sensible diligence step in any of the OU-affected ZIP codes.

Frequently Asked Questions

Is chromium-6 in LADWP water?

Yes. LADWP detects Cr-VI in its tap water at trace concentrations and reports it in the annual Consumer Confidence Report. Concentrations are typically low because most San Fernando Valley groundwater wells are offline or treated, and the Owens Valley source has low natural Cr-VI. Routine LADWP tap water is far below the 100 ppb federal total chromium MCL but above the 0.02 ppb California notification level.

What is the California notification level for chromium-6?

The California State Water Resources Control Board sets the Cr-VI notification level at 0.02 ppb. Utilities that exceed it must notify the SWRCB. This is not an enforceable MCL (the 2014 MCL of 10 ppb was withdrawn in 2017 and is currently being re-adopted), but it functions as the practical state regulatory benchmark for Cr-VI in drinking water.

Does a water softener remove chromium-6?

No. Sodium-cycle ion exchange water softeners exchange calcium and magnesium for sodium. They do not exchange chromate ions and have no measurable effect on Cr-VI. If Cr-VI is your concern, you need reverse osmosis or specialty anion exchange. A softener and an RO system work together but address different problems.

How much does an RO system cost in Los Angeles?

An NSF/ANSI 58 certified under-sink RO system installed by a licensed contractor in LA County typically runs $1,800 to $2,800 for a standard residential system, $2,200 to $3,200 with the P473 PFAS endorsement, and $6,000 to $12,000 for whole-house RO. Annual filter service runs $150 to $250. See LA RO cost guide for current Water₂O pricing.

Is the San Fernando Valley plume still active?

Yes. EPA documentation of the San Fernando Valley Superfund sites shows pump-and-treat groundwater remediation will continue for the foreseeable future. The plume is not migrating rapidly thanks to active extraction wells, but contaminant concentrations in untreated groundwater remain elevated in core plume zones.

Do I need to test my LA tap water for chromium-6?

If you are on LADWP, Burbank Water and Power, or Glendale Water and Power municipal supply, your utility tests for Cr-VI and publishes results in the annual CCR. Independent testing is not strictly necessary unless you have a sensitive household member or want to verify the performance of an installed RO system. If you are on a private well anywhere in the San Fernando Valley, annual Cr-VI testing is strongly recommended.

Get Tested. Get Treated. Get on with Your Life.

Chromium-6 in LA tap water is a real but manageable problem. The California notification level of 0.02 ppb is conservative, the federal compliance picture is reassuring, and the Burbank and Glendale Operable Units are under active EPA management. The honest summary: most LA homes do not have a Cr-VI crisis, but every LA home benefits from NSF/ANSI 58 RO at the kitchen tap. For homes near the OU plumes or with sensitive household members, that recommendation tightens to "essential."

Water₂O has installed 500-plus systems across LA County since 2011. We test first, then recommend. Every install backed by our 12-year warranty and 4.9-star service record.