Is St. Louis tap water safe to drink?

Yes but with caveats

St. Louis's water meets EPA minimum standards but has some concerns including PFAS detected. Filtration is recommended for sensitive individuals.

64/100
Purity Score
4
Issues Found
7.5 GPG
Hardness
Detected
PFAS

4 Issues Detected in St. Louis

PFAS (Forever Chemicals) Detected

PFAS are man-made chemicals that do not break down and accumulate in the body.

PFAS details for St. Louis

Moderately Hard Water (7.5 GPG)

Hardness above 7 GPG can cause minor scale buildup.

Hardness data for St. Louis

Moderate Chlorine Level

Chlorine within EPA limits but may affect taste.

Chlorine info for St. Louis

Arsenic Approaching Limit (0.3 mg/L)

EPA limit is 0.010 mg/L.

Arsenic info for St. Louis
Missouri

631,016,310,263,103 · Missouri and Mississippi Rivers

St. Louis Water Quality Report: PFAS Detected

Elevated Risk Updated March 2026 1.3M residents
See Best Filters for St. Louis
64
Purity Score

This 2026 analysis examines St. Louis's water supply with a focus on PFAS exposure, hardness, and overall safety. Data is sourced from EPA SDWIS, EWG, and Missouri American Water consumer confidence reports.

Contaminant Levels

PFAS
2.7 ppt
Lead
5.5 ppb
Nitrate
1.2 mg/L
Arsenic
0.3 mg/L
Hardness
7.5 gpg

Health Insights

  • 1
    At 7.5 GPG, St. Louis's water qualifies as moderately hard. This can cause limescale in pipes and shorten appliance lifespan.
  • 2
    PFAS have been identified in St. Louis's water at 2.7 parts per trillion. A reverse osmosis system is the most reliable home treatment.
  • 3
    Chlorine levels may affect the taste of St. Louis's tap water. A carbon filter improves flavor.

Score

64 /100
Moderate
"Good" threshold (70)

St. Louis tap water is sourced from Missouri and Mississippi Rivers and treated by Missouri American Water. PFAS forever chemicals have been detected. Water hardness is hard at 7.5 GPG which may cause scale buildup. Overall purity score: 64/100 (Moderate). Updated for 2026.

Fix Your Water

Best filters matched to St. Louis's 4 issues.

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About St. Louis's Water

Understanding PFAS in St. Louis's Water Supply

PFAS (per- and polyfluoroalkyl substances) are a class of synthetic chemicals used in industrial and consumer products since the 1940s. Testing identified PFAS compounds in St. Louis's water at 2.7 parts per trillion. These chemicals resist breakdown in the environment and the human body, which is why they're sometimes called forever chemicals. The EPA has established health advisories for several PFAS compounds. A certified reverse osmosis system removes 99% or more of PFAS from drinking water and is currently the most reliable home treatment option.

Hard Water in St. Louis: Impact on Plumbing and Appliances

At 7.5 grains per gallon, St. Louis's water qualifies as hard. Hard water carries dissolved calcium and magnesium that deposit as limescale inside pipes, water heaters, dishwashers, and washing machines over time. Scale accumulation reduces appliance efficiency and shortens service life. A salt-based water softener is the most effective solution for whole-home protection. For drinking water only, a reverse osmosis system also reduces mineral content significantly.

Explore St. Louis Water Data

PFAS Levels in St. LouisPFAS testing data
St. Louis Lead LevelsLead testing data
Water Hardness in St. LouisHardness levels
Best FiltersFull comparison
MissouriState rankings

St. Louis Water FAQ

Is St. Louis MO tap water safe to drink in 2026?
St. Louis tap water meets EPA federal drinking water standards and scores 64/100 (Moderate) on PurityMap for 2026. PFAS forever chemicals have been detected at 2.7 ppt. An NSF-certified filter is strongly recommended. For most healthy adults the water is considered safe but point-of-use filtration adds an important layer of protection.
Does St. Louis MO use chlorine or chloramine for disinfection?
St. Louis uses chloramine as the primary disinfectant with a residual level of 1.7 ppm. Chloramine is harder to remove than free chlorine and requires a catalytic carbon or reverse osmosis filter. Standard Brita-style pitchers will NOT remove chloramine.
How hard is St. Louis MO water and what is the TDS level?
St. Louis water hardness is 7.5 grains per gallon (hard) with a TDS of 265 ppm (fair). This level causes noticeable scale buildup in water heaters kettles and dishwashers. A water softener is recommended to protect plumbing and reduce soap usage.
Has PFAS been found in St. Louis MO drinking water?
Yes. PFAS forever chemicals have been detected in St. Louis water at approximately 2.7 ppt according to EPA UCMR5 monitoring data. A reverse osmosis or NSF P473-certified filter is the most effective residential solution.
What is the best water filter for St. Louis?
Based on St. Louis's water profile, we recommend the Clearly Filtered Water Pitcher. St. Louis: PFAS detected or elevated lead risk. Reverse osmosis is the only residential technology proven to reduce both below detection limits. TDS will also drop significantly.

Nearby Reports

Kansas CityMissouri — 78/100IndependenceMissouri — 78/100Lee's SummitMissouri — 78/100ColumbiaMissouri — 79/100O'FallonMissouri — 79/100SpringfieldMissouri — 82/100

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Data Sources

  • EPA SDWIS
  • EWG Tap Water Database
  • Missouri American Water CCR
  • USGS monitoring data

PurityMap compiles public data. Updated March 2026.

© 2026 PurityMap. For informational purposes only.

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