Mineral or dissolved constituent

Calcium in water reports

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.

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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:
Mineral or dissolved constituent
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

Calcium is one of the dissolved mineral ions commonly present in water. USGS identifies calcium and magnesium as the main contributors to water hardness.

Why it may appear in a report

A utility may list calcium in a customer-interest table to describe mineral composition and help readers understand related aggregate characteristics.

How it may be labeled

Other names you may see
Calcium
Label in Silver City's report
Calcium

Measurement context

How to read the unit and measure

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

Keep the report's printed value and unit together. Silver City prints a PPM average and range, but the row does not print a sampling year, regulatory criterion, hardness value, or TDS value.

Units used in reviewed sources

  • PPM as printed by the report
  • mg/L in some official sources

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 calcium. The row remains mineral-composition evidence, not a federal violation finding.

2025 report example

Silver City's 2025 report: Calcium

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:

Calcium

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: 49.13
Range in report
Range: 29.9 - 60.3
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 customer-interest table does not print a sample year or regulatory limit for this row.

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. Confirm the exact report label, unit, average, and range.
  2. Read calcium alongside separately reported hardness or TDS only without combining the values.
  3. Use official provider or NMED sources for current status and instructions.

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.

Water chemistry characteristic

Hardness

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.

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