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City water profile

Water hardness in St. Louis

Find official utility reports, understand hardness, and check the water system serving your home in St. Louis, Missouri.

Utility-reported hardness

Not yet available

Check your provider and source →
State comparison
Unavailable
Evidence comparison rank
—
Matched utilities
1
Active health records
0

Your tap water

What does the utility report?

Match the utility name to your water bill. These results describe the utility’s water, not a test at your home. A ZIP can include several water systems.

Utility hardness unavailable in this index

Nearby river or groundwater samples cannot tell us the hardness coming out of your tap. Ask your water provider for total hardness as CaCO₃, or test it at home.

Find an official utility report →
Convert a hardness result →Test your tap →

Match the name on your water bill

Your utility’s measurements and compliance records

These are possible serving systems. A record for one system does not apply to every home in this ZIP. Confirm your provider before interpreting a measurement or notice. Federal records can lag current utility notices.

EPA snapshot: 2026Q2. Historical window begins Jan 1, 2021.

St Louis City Pws

MO6010715 · Surface water · 304,709 people served system-wide

The system names this served city; Census place overlap links the city to this ZCTA.

No active health-based record in this imported snapshot

Find this utility’s official report →
Measurements (1)

An action level is a regulatory trigger, not a pass/fail health boundary. A reported zero is the value in the source record and does not establish that lead is absent at your tap.

Lead (90th percentile)

EPA SDWIS Lead and Copper Rule samples

Below action level
Reported level
0.0018 mg/L
Action level
0.015 mg/L

12% of the listed benchmark

Monitoring period: Jan 1, 2023 to Dec 31, 2025

Violation history (8)
Imported violation history for St Louis City Pws
RuleStatusPeriod
Lead and Copper RuleUnaddressedDec 30, 2025
LEAD AND COPPER RULE REVISIONSUnaddressedJul 2, 2025
SimazineResolvedOct 1, 2022 to Dec 31, 2022
AtrazineResolvedOct 1, 2022 to Dec 31, 2022
LASSOResolvedOct 1, 2022 to Dec 31, 2022
AtrazineResolvedJul 1, 2022 to Sep 30, 2022
LASSOResolvedJul 1, 2022 to Sep 30, 2022
SimazineResolvedJul 1, 2022 to Sep 30, 2022

City summary

What the indexed records say

St. Louis has 19 published ZIP profiles across St. Louis City County. The regional-evidence median is 227 PPM. The city does not meet the stricter comparison standard.

The 215–257 PPM range shows how much the available ZIP estimates vary within the city label.

Hardness distribution

How local ZIP estimates compare

Soft0 ZIPs
Moderately hard0 ZIPs
Hard0 ZIPs
Very hard19 ZIPs

19 of 19 ZIP profiles have a hardness estimate. Bars count ZIP profiles, not households or laboratory samples.

Evidence quality

Distance, dates, and confidence

Median nearest distance
14.9 miles
Profiles with evidence
19/19

Confidence labels

High: 0Moderate: 19Low: 0

Observation window: Aug 12, 2019 to Jun 9, 2026.

ZIP directory

Water reports in St. Louis

Open a ZIP for site-level provenance and measurements.

ZIP code

63101

Very Hard

227 PPM

Nearest site
16.7 mi
Confidence
Moderate

View full ZIP evidence →

ZIP code

63102

Very Hard

227 PPM

Nearest site
17.1 mi
Confidence
Moderate

View full ZIP evidence →

ZIP code

63103

Very Hard

227 PPM

Nearest site
15.7 mi
Confidence
Moderate

View full ZIP evidence →

ZIP code

63104

Very Hard

227 PPM

Nearest site
14.9 mi
Confidence
Moderate

View full ZIP evidence →

ZIP code

63106

Very Hard

227 PPM

Nearest site
16.8 mi
Confidence
Moderate

View full ZIP evidence →

ZIP code

63107

Very Hard

227 PPM

Nearest site
15.5 mi
Confidence
Moderate

View full ZIP evidence →

ZIP code

63108

Very Hard

227 PPM

Nearest site
15.3 mi
Confidence
Moderate

View full ZIP evidence →

ZIP code

63109

Very Hard

257 PPM

Nearest site
10.6 mi
Confidence
Moderate

View full ZIP evidence →

ZIP code

63110

Very Hard

227 PPM

Nearest site
13.8 mi
Confidence
Moderate

View full ZIP evidence →

ZIP code

63111

Very Hard

215 PPM

Nearest site
11.1 mi
Confidence
Moderate

View full ZIP evidence →

ZIP code

63112

Very Hard

227 PPM

Nearest site
15.4 mi
Confidence
Moderate

View full ZIP evidence →

ZIP code

63113

Very Hard

227 PPM

Nearest site
16.2 mi
Confidence
Moderate

View full ZIP evidence →

ZIP code

63115

Very Hard

227 PPM

Nearest site
14.5 mi
Confidence
Moderate

View full ZIP evidence →

ZIP code

63116

Very Hard

215 PPM

Nearest site
11.4 mi
Confidence
Moderate

View full ZIP evidence →

ZIP code

63118

Very Hard

215 PPM

Nearest site
13.6 mi
Confidence
Moderate

View full ZIP evidence →

ZIP code

63120

Very Hard

227 PPM

Nearest site
14.2 mi
Confidence
Moderate

View full ZIP evidence →

ZIP code

63139

Very Hard

227 PPM

Nearest site
12.2 mi
Confidence
Moderate

View full ZIP evidence →

ZIP code

63147

Very Hard

227 PPM

Nearest site
13.5 mi
Confidence
Moderate

View full ZIP evidence →

ZIP code

63155

Very Hard

227 PPM

Nearest site
16.1 mi
Confidence
Moderate

View full ZIP evidence →

Practical next steps

Move from index to evidence

  1. 1. Open your ZIP. Check distance, dates, confidence, and the associated utility.
  2. 2. Read the current CCR. Confirm source water, detections, limits, ranges, and notices.
  3. 3. Use a measured hardness result. Confirm health concerns or treatment sizing with the right method.

Questions people ask

About water in St. Louis

Is the water hard?

Check the utility-reported result above when available. Nearby environmental samples cannot establish tap-water hardness. Ask your provider or test your tap.

Is the tap water safe?

Compliance history is utility-wide and cannot guarantee conditions at every tap. Check current notices and test when address-specific evidence is needed.

Do I need treatment?

Choose treatment only after confirming the problem at the property. A softener targets hardness; contaminant treatment requires a matching, verified performance claim.