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City water profile

Water hardness in San Marcos

Find official utility reports, understand hardness, and check the water system serving your home in San Marcos, Texas.

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.

City Of San Marcos

TX1050001 · Surface water · 72,970 people served system-wide

A municipal system, in-state city, and served county all agree with this Census ZCTA.

No active health-based record in this imported snapshot

Find this utility’s official report →
Measurements (2)

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
0.0016 mg/L
Action level
0.015 mg/L

11% of the listed benchmark

Monitoring period: Jan 1, 2022 to Dec 31, 2024

TTHM

EPA SDWIS reported health-based violation

Reported violation
Reported level
0.081 MG/L
Maximum contaminant level
0.08 MG/L

101% of the listed benchmark

Monitoring period: Oct 1, 2025 to Dec 31, 2025

Violation history (2)
Imported violation history for City Of San Marcos
RuleStatusPeriod
TTHMHealth-basedResolvedOct 1, 2025 to Dec 31, 2025
ChloriteResolvedFeb 1, 2021 to Feb 28, 2021

City summary

What the indexed records say

San Marcos has 1 published ZIP profile across Hays County. The regional-evidence median is 277 PPM. The city does not meet the stricter comparison standard.

Because only one ZIP is represented, the city median and range are the same local estimate. It should not be read as multiple independent samples across the community.

Hardness distribution

How local ZIP estimates compare

Soft0 ZIPs
Moderately hard0 ZIPs
Hard0 ZIPs
Very hard1 ZIP

1 of 1 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 miles
Profiles with evidence
1/1

Confidence labels

High: 0Moderate: 1Low: 0

Observation window: Jan 29, 2024 to Jul 15, 2025.

ZIP directory

Water reports in San Marcos

Open a ZIP for site-level provenance and measurements.

ZIP code

78666

Very Hard

277 PPM

Nearest site
14 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 San Marcos

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.