Water chemistry characteristic

Hardness in water reports

Hardness is an aggregate water characteristic driven mainly by dissolved calcium and magnesium. It can affect soap performance and mineral scale without being a primary contaminant standard.

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Federal scienceSource review:

This is a report-reading explainer. It is not a live advisory, household result, violation decision, or personal health assessment.

Report example:
1 entry from Silver City's 2025 report illustrates this term.
Type of report term:
Water chemistry characteristic
Report-period evidence:
An annual-report row is evidence for the named report and source period, not a live monitoring result.
Current instructions:
Current status and instructions must come from the water provider, NMED, or another appropriate official source.

Meaning and report use

What the term means

USGS describes hardness as the amount of dissolved calcium and magnesium in water. It is an aggregate property, not one individual substance.

Why it may appear in a report

Utilities may include hardness because it can help explain mineral scale, soap behavior, and other practical water-use observations.

How it may be labeled

Other names you may see
Hardness; Water hardness
Label in Silver City's report
Hardness

Measurement context

How to read the unit and measure

Values remain attached to the labels, units, and table context printed by the official report.

Hardness is often expressed on a calcium-carbonate basis, and reports may also print grains per gallon. Silver City's average text is preserved exactly, including its unclosed parenthesis, and this page does not replace the utility's descriptor with a generic classification band.

Units used in reviewed sources

  • PPM as printed by the report
  • mg/L as CaCO3
  • grains per gallon

Standards and reporting context

How this term fits the official framework

Primary standards, secondary standards, special monitoring, and customer-interest reporting are not interchangeable.

No reviewed federal primary or secondary level

The reviewed current EPA Part 141 primary table and Part 143 secondary table do not establish a federal MCL or secondary level for hardness. USGS discusses hardness as a water property with practical effects.

2025 report example

Silver City's 2025 report: Hardness

The values below use the report's original labels and units. They have not been converted or used to make a compliance finding.

Official report rowReport source retrieved:

Hardness

The Town of Silver City lists this value in the table titled “Substances of Frequent Interest to Customers.” The table does not give a testing year or regulatory criterion for this entry.

Public water system
Silver City Water System
Report
2025 Water Quality Report
Reported measurement
Average: 162 (Medium Hardness or 9.45 Grains/Gallon
Range in report
Range: 132 - 200
Unit
PPM
Testing period in table
Not printed in table
Regulatory criterion in row
Not printed in row
Status in row
Not printed in row
Source table
Substances of Frequent Interest to Customers
Source page
3

The average cell is preserved without supplying a closing parenthesis that is not printed in the source.

Open the exact row in the Silver City report summary

Interpretation boundaries

What the row does not establish

These limits apply even when a result is printed clearly in an annual report.

What to verify next

  1. Read the report's measurement basis, unit, range, and average together, using the wording as printed.
  2. Use the utility if you need its intended hardness classification method.
  3. Check current provider or NMED sources rather than treating the annual row as live status.

Related report terms

Explore related report terms

These terms describe related water properties or measurements. Each page explains its own result from Silver City's report.

Water chemistry characteristic

Alkalinity

Alkalinity describes water's capacity to neutralize acids and bases and resist rapid pH change. It is a water property, not a contaminant identity or the same thing as pH.

Mineral or dissolved constituent

Calcium

Calcium is a dissolved mineral constituent that can contribute to hardness and total dissolved solids. Its individual report row is not the same as either aggregate measure.

Aesthetic or operational characteristic

Iron

Iron has federal secondary-standard context focused primarily on aesthetic and operational considerations. That secondary value is not a federal primary health-based MCL.

Official sources

Sources reviewed for this explainer

Every source records its publisher, retrieval and review date, version note, and the claims it supports.

Evidence

Official source path

Use official federal, state, utility, or report sources before treating a page as final.

Continue reading

Related interpretation paths

Use the separate directory, contaminant library, report-reading guide, and methodology according to the question you are trying to answer.

Contaminants directory

Use the separate contaminant library for primary standards, action levels, disinfectants, monitoring topics, and treatment measures.

View Contaminants directory

Data methodology

See how source records, annual-report evidence, limitations, and current-status boundaries are handled.

View Data methodology