Is Arnold, MO Tap Water Safe to Drink?
Graded B — but Chlorate was detected above EPA limits. Here's what's in the water and how to remove it. What to do next ↓
79.2/100
waterverge.com Arnold, MO — Water Quality Report
Arnold's drinking water received a grade of B (79.2 out of 100), indicating good water quality. The city's 5 water systems serve approximately 38,712 residents using purchased surface water.
Lead levels were measured at 7.3 ppb (90th percentile), which is within EPA limits but above recommended levels. PFAS testing under UCMR 5 found no detectable forever chemicals.
The system has 9 violations on record, including 0 health-based violations. 6 remain unresolved.
What to know about Arnold's water
Arnold ranks #324 out of 509 cities in Missouri for water quality, placing it below average in the state.
The city draws from surface water sources, which are more susceptible to seasonal runoff and agricultural contamination, requiring extensive multi-barrier treatment including coagulation, filtration, and disinfection.
Haloacetic acid (HAA5) levels were elevated at 30.0 µg/L in UCMR 4 testing, though below the 60 µg/L EPA limit. Activated carbon filtration can help reduce these disinfection byproducts.
Hexavalent chromium (chromium-6) was detected at 2.00 µg/L in UCMR 3 testing. While below California's 10 µg/L limit and with no federal MCL set, residents sensitive to this contaminant may consider reverse osmosis filtration.
While lead levels are within EPA limits, they are above the recommended 5 ppb threshold that health organizations consider ideal. A point-of-use filter adds an extra layer of protection.
Water quality score
See methodology →Is Arnold, MO water safe to drink?
Arnold's drinking water has significant quality concerns based on EPA testing data. With a grade of B (79.2/100), the system has issues across multiple categories. A water filter is recommended for all residents. The city's 5 water systems serve approximately 38,712 residents using surface water (rivers, lakes, or reservoirs).
Recent water quality updates for Arnold
A timeline of significant water quality events, violations, and data updates.
Latest EPA compliance and testing data incorporated into Arnold's water quality assessment. Grade: B (79.2/100).
Contaminants: Lead and Copper Rule.
Contaminants: TTHM, Total Haloacetic Acids (HAA5).
Federal disaster declaration (FEMA DR-4317). Flood event — may have impacted local water infrastructure.
Federal disaster declaration (FEMA DR-4250). Flood event — may have impacted local water infrastructure.
Contaminants: Consumer Confidence Rule.
Key contaminant findings
Based on the most recent EPA sampling data for Arnold's water supply.
Within EPA limits but above the American Academy of Pediatrics recommended level of 1 ppb. An NSF 53-certified filter provides additional protection.
Violation history
Arnold's water system has 9 total violations on record, including 0 health-based violations. 6 remain unresolved. 3 violations were issued in the last 5 years.
Flood & environmental risk
Jefferson County has experienced 9 federally declared disasters since 1982. Flooding and severe storms can overwhelm water treatment plants, cause sewage overflows, and introduce agricultural runoff, bacteria, and sediment into drinking water supplies. Local water sources include Grammond Creek Near Wilbur Park, River Des Peres At St. Louis, Gravois Creek Near Mehlville, Martigney Creek Near Arnold, Williams Creek Near Peerless Park.
Where does Arnold's water come from?
Arnold's drinking water comes from surface water (rivers, lakes, or reservoirs), supplied by 5 water systems serving approximately 38,712 people. Surface water sources are more susceptible to contamination from runoff, industrial discharge, and algal blooms, requiring extensive treatment. Nearby water bodies include Grammond Creek Near Wilbur Park (river), River Des Peres At St. Louis (river), Gravois Creek Near Mehlville (river), Martigney Creek Near Arnold (river), Williams Creek Near Peerless Park (river).
What Arnold residents can do
Recommended: NSF-certified water filter. This addresses the specific contaminants found in Arnold's water.
Your water utility is required to publish an annual Consumer Confidence Report (CCR) with detailed testing results. Ask for the latest copy or check your utility's website.
Run cold water for 30 seconds before drinking, especially in the morning. Lead and copper leach from household plumbing when water sits in pipes.
Arnold's area has a history of flooding. After severe weather, watch for boil water advisories from your local utility.
Data: EPA SDWIS, UCMR 5 (PFAS), FEMA, NOAA. Last updated May 2026.
Top contaminants to know
View all ↓Forever chemicals overview
National PFAS report →Violation summary
Violations & advisories
Top industrial polluters within 10 miles of Arnold
Industrial polluters nearby
Reported releases to surface water by facilities near Arnold, ranked by pounds discharged annually.
| Facility | Top chemical | To surface water (lbs/yr) | Distance |
|---|---|---|---|
METAL CONTAINER CORP - ARNOLD CAN PLANT ARNOLD, MO63010 | — | — | 0.8 mi |
SUPERIOR INDUSTRIAL SOLUTIONS INC. ARNOLD, MO63010 | — | — | 1.0 mi |
ST LOUIS MARBLE CO FENTON, MO63026 | — | — | 8.6 mi |
CONTROL DEVICES FENTON, MO63026 | — | — | 8.8 mi |
KILLARK A DVISION OF HUBBELL FENTON, MO63026 | — | — | 9.7 mi |
Source: EPA Toxic Release Inventory (TRI) 2023
Superfund sites within 10 miles of Arnold
Superfund sites nearby
Federally tracked hazardous-waste sites on the EPA National Priorities List. Proximity does not necessarily indicate tap-water contamination — the connection depends on hydrology and treatment.
- MINKER STOUT ROMAINE CREEK6.1 mi
Source: EPA Superfund National Priorities List
Flood & disaster history
Jefferson County has experienced 9 federally declared disasters since 1982. Flooding and severe weather can compromise water treatment infrastructure and introduce contaminants into drinking water supplies.
Recommended water filters
Based on contaminants detected in Arnold's water supply, we recommend the following filter types.
Full contaminants report
| Contaminant | Detected Level | EPA Limit | Unit | Category | Status |
|---|---|---|---|---|---|
| Lead (90th percentile) LeadHeavy Metal A toxic heavy metal that can leach into drinking water from older pipes, solder, and fixtures. No amount of lead in water is considered safe. Health EffectsBrain and nervous system damage in children, kidney damage, high blood pressure, and reproductive problems in adults. EPA Limit15 ppb action level Common SourcesCorrosion of lead pipes, lead solder, brass faucets, and household plumbing. | 7.3 | 15 | ppb | Inorganic | Safe |
| 11Cl-PF3OUdS | ND | HI | µg/L | PFAS | Not Detected |
| 4:2 FTS | ND | HI | µg/L | PFAS | Not Detected |
| 6:2 FTS 6:2 FTSPFAS A fluorotelomer sulfonate commonly found at sites contaminated with aqueous film-forming foam (AFFF) used in firefighting. Health EffectsPotential liver toxicity and endocrine disruption. Less studied but identified as a contaminant of concern. EPA LimitNo individual MCL (not yet regulated) Common SourcesFirefighting foam (AFFF), airports, military bases, and industrial facilities. | ND | HI | µg/L | PFAS | Not Detected |
| 8:2 FTS | ND | HI | µg/L | PFAS | Not Detected |
| 9Cl-PF3ONS | ND | HI | µg/L | PFAS | Not Detected |
| ADONA | ND | HI | µg/L | PFAS | Not Detected |
| HFPO-DA HFPO-DA (GenX)PFAS A replacement for PFOA in manufacturing, marketed as safer but still a persistent "forever chemical." Also known as GenX. Health EffectsLiver and kidney effects, reproductive toxicity, immune system effects, and potential cancer risk. EPA Limit10 ppt MCL Common SourcesFluoropolymer manufacturing (used as PFOA replacement), industrial wastewater discharge. | ND | 0.01 | µg/L | PFAS | Not Detected |
| lithium LithiumInorganic A naturally occurring alkali metal found in groundwater. Monitored under UCMR 5 to assess occurrence in drinking water. Health EffectsKidney effects at high doses. Low-level exposure effects under study; some research suggests neurological effects. EPA LimitNo MCL (monitoring only under UCMR 5) Common SourcesNatural mineral deposits, geothermal water, and industrial discharge. | ND | HI | µg/L | PFAS | Not Detected |
| NEtFOSAA | ND | HI | µg/L | PFAS | Not Detected |
| NFDHA | ND | HI | µg/L | PFAS | Not Detected |
| NMeFOSAA | ND | HI | µg/L | PFAS | Not Detected |
| PFBA PFBAPFAS One of the shortest-chain PFAS compounds. Very mobile in water and difficult to remove with standard filtration. Health EffectsThyroid effects, potential developmental toxicity. Shorter half-life in body than long-chain PFAS. EPA LimitNo individual MCL (not yet regulated) Common SourcesDegradation of longer-chain PFAS, industrial discharge, and firefighting foam. | ND | HI | µg/L | PFAS | Not Detected |
| PFBS PFBSPFAS A short-chain PFAS used as a replacement for PFOS. While it clears the body faster than long-chain PFAS, it still persists in the environment. Health EffectsThyroid effects, reproductive and developmental toxicity, kidney effects. EPA LimitPart of Hazard Index (1.0) Common SourcesIndustrial discharge, firefighting foam, and as a replacement chemical in manufacturing. | ND | HI | µg/L | PFAS | Not Detected |
| PFDA | ND | HI | µg/L | PFAS | Not Detected |
| PFDoA | ND | HI | µg/L | PFAS | Not Detected |
| PFEESA | ND | HI | µg/L | PFAS | Not Detected |
| PFHpA PFHpAPFAS A medium-chain PFAS compound found in various environmental samples. Less studied than PFOA/PFOS but still considered a contaminant of concern. Health EffectsLiver effects, potential developmental toxicity, and endocrine disruption. EPA LimitPart of Hazard Index (1.0) Common SourcesDegradation of longer-chain PFAS, industrial discharge, and contaminated water sources. | ND | HI | µg/L | PFAS | Not Detected |
| PFHpS | ND | HI | µg/L | PFAS | Not Detected |
| PFHxA PFHxAPFAS A short-chain PFAS replacement chemical widely used after manufacturers phased out longer-chain PFAS. Very commonly detected in water. Health EffectsLiver and kidney effects, potential thyroid disruption. Considered less toxic than long-chain PFAS but still persistent. EPA LimitNo individual MCL (not yet regulated) Common SourcesIndustrial processes, firefighting foam (AFFF), food packaging, and textile treatment. | ND | HI | µg/L | PFAS | Not Detected |
| PFHxS PFHxSPFAS A medium-chain PFAS found in firefighting foam and consumer products. It has a long half-life in the human body, similar to long-chain PFAS. Health EffectsImmune system effects, thyroid disruption, and potential reproductive and developmental harm. EPA LimitPart of Hazard Index (1.0) Common SourcesFirefighting foam (AFFF), waterproof textiles, food packaging, and industrial discharge. | ND | HI | µg/L | PFAS | Not Detected |
| PFMBA | ND | HI | µg/L | PFAS | Not Detected |
| PFMPA | ND | HI | µg/L | PFAS | Not Detected |
| PFNA PFNAPFAS A long-chain PFAS compound used in manufacturing fluoropolymers. It bioaccumulates in the body and is very persistent in the environment. Health EffectsDevelopmental effects, liver toxicity, immune suppression, and potential cancer risk. EPA LimitPart of Hazard Index (1.0) Common SourcesFluoropolymer manufacturing, industrial emissions, and contaminated water sources. | ND | HI | µg/L | PFAS | Not Detected |
| PFOA PFOAPFAS A long-chain PFAS ("forever chemical") once widely used in nonstick coatings and firefighting foam. It persists in the body and environment for years. Health EffectsLinked to kidney and testicular cancer, thyroid disease, elevated cholesterol, and reproductive issues. EPA Limit4.0 ppt MCL Common SourcesIndustrial discharge, firefighting foam (AFFF), nonstick cookware manufacturing, and contaminated groundwater. | ND | 0.004 | µg/L | PFAS | Not Detected |
| PFOS PFOSPFAS A long-chain PFAS compound historically used in stain-resistant coatings and firefighting foam. One of the most studied and persistent PFAS chemicals. Health EffectsLiver damage, immune system suppression, thyroid disruption, increased cholesterol, and potential cancer risk. EPA Limit4.0 ppt MCL Common SourcesFirefighting foam (AFFF), industrial sites, stain-resistant fabric treatments, and contaminated groundwater. | ND | 0.004 | µg/L | PFAS | Not Detected |
| PFPeA PFPeAPFAS A short-chain PFAS compound commonly detected in drinking water. One of the most frequently found PFAS in UCMR 5 monitoring. Health EffectsLess studied than PFOA/PFOS. Potential liver and thyroid effects. Research is ongoing. EPA LimitNo individual MCL (not yet regulated) Common SourcesIndustrial discharge, firefighting foam degradation, and consumer products. | ND | HI | µg/L | PFAS | Not Detected |
| PFPeS | ND | HI | µg/L | PFAS | Not Detected |
| PFTA | ND | HI | µg/L | PFAS | Not Detected |
| PFTrDA | ND | HI | µg/L | PFAS | Not Detected |
| PFUnA | ND | HI | µg/L | PFAS | Not Detected |
Lead level trend (90th percentile)
See how Arnold compares by contaminant
Explore where Arnold ranks among all Missouri cities for specific contaminants.
Water source & infrastructure
Where Arnold's water comes from
Arnold's drinking water comes primarily from surface water sources such as rivers, lakes, or reservoirs.
Surface water systems require multi-stage treatment including coagulation, sedimentation, filtration, and disinfection to meet EPA Safe Drinking Water Act standards.
These sources can be impacted by seasonal changes, stormwater runoff, upstream agriculture, and industrial discharge.
The system is operated by local government ownership and serves approximately 38,712 people through 5 water systems.
Water bodies near Arnold
Arnold is located near 5 notable water bodies. As a surface water system, these water bodies may directly influence the city's drinking water supply.
Water systems serving Arnold
| System Name | PWSID | Population | Source |
|---|---|---|---|
| JEFFERSON COUNTY PWSD 1 | MO6024292 | 21,113 | SWP |
| JEFFERSON COUNTY PWSD 3 | MO6024294 | 17,000 | SWP |
| STARLING MHP | MO6046374 | 342 | SWP |
| OZARK HILLS MHP | MO6046375 | 230 | SWP |
| LYNN ACRES MHP | MO6046381 | 27 | GWP |
How Arnold compares
Full Missouri rankings →Arnold's score of 79.2/100 is above the average of 62/100 among major Missouri cities. It outscores 6 of 10 nearby cities.
Nearby cities
View Missouri rankings →About Arnold, MO
Wikipedia →Arnold is a city in northeastern Jefferson County, Missouri, situated near the confluence of the Meramec and Mississippi rivers. A suburb of St. Louis, the city lies within the Greater St. Louis metropolitan statistical area. The population was 20,858 at the 2020 United States census, which makes it the most populous community in the county.
Learn more about your water
Guides and resources related to Arnold's water quality findings.
Explore water quality across Jefferson
Frequently asked questions
Is Arnold, MO tap water safe to drink?
Arnold's water quality earned a grade of B (79.2/100). Some concerns have been identified. Consider a water filter for an extra layer of protection. The city ranks #324 out of 509 cities tested in Missouri.
What contaminants are in Arnold's water?
Lead was measured at 7.3 ppb (90th percentile). No PFAS compounds were detected. 9 violations are on record.
How is Arnold's water quality grade calculated?
The grade is based on four factors: violation history (40%), lead and copper levels (25%), PFAS contamination (25%), and regulatory compliance (10%). The score is also adjusted based on how complete the available data is. See our methodology page for full details.
Do I need a water filter in Arnold?
While lead levels are within EPA limits, a filter adds extra protection. Based on current data, basic filtration should suffice for additional peace of mind.
Where does Arnold's water come from?
Arnold's water is sourced from Purchased surface water. The city has 5 water systems serving approximately 38,712 residents.
How does Arnold's water compare to other cities?
Arnold ranks #324 out of 509 cities in Missouri (better than 36% of state cities) and #8325 out of 15744 cities nationally (47th percentile). The grade of B reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.