Term Identity
What the term means in an annual report
HAA5 is a regulated group measurement for five specified haloacetic acids rather than one individual compound.
Why it may appear
Systems report HAA5 because disinfectants can react with material in source water and produce regulated byproducts monitored at distribution-system locations.
How it may be printed
Reports may use HAA5 or Haloacetic Acids and show a highest locational running annual average, individual-sample range, MCL field, and printed status.
- Other names you may see
- HAA5; Haloacetic Acids; Haloacetic Acids (HAA5)
- Common report labels
- HAA5; Haloacetic Acids; Haloacetic Acids [HAA5]
Evidence
Official sources for this explainer
Use official federal, state, utility, or report sources before treating a page as final.
EPA data
EPA Stage 1 and Stage 2 Disinfectants and Disinfection Byproducts Rules (opens official source)
- Supports
- HAA5 identity; Stage 2 location and averaging context
- Retrieved
- 2026-07-11
- Reviewed
- 2026-07-11
Federal regulation
- Supports
- HAA5 group definition; Regulatory terminology
- Retrieved
- 2026-07-11
- Reviewed
- 2026-07-11
- Supports
- Highest LRAA and range presentation; CCR context
- Retrieved
- 2026-07-11
- Reviewed
- 2026-07-11
- Supports
- Annual-report purpose and reporting context; Report-period interpretation and official next steps
- Retrieved
- 2026-07-11
- Reviewed
- 2026-07-11
Regulatory Context
How to read the applicable rule language
Use this Haloacetic acids (HAA5) context to read a report's printed fields; it does not replace the report or the current official rule.
Framework
Stage 2 compliance uses the locational running annual average at each monitoring location. The individual-sample range supplies context but is not independently compared with the MCL to create a violation conclusion.
Limit or program terms
- MCL
- Locational running annual average
- Individual-sample range
Units and source context
Read the reported statistic, location or averaging context, range, unit, and report period together.
What this page does not duplicate
There is no collective HAA5 MCLG. Individual constituents can have separate goals, which should not be presented as one HAA5 value.
No standalone numeric limit table is rendered here. Read the source report's printed criterion and the current official source together.
Interpretation Boundaries
What a listed result does not establish
These Haloacetic acids (HAA5) boundaries apply to every report row connected to this explainer.
Household-level boundary
A report's HAA5 statistic does not establish a current result at a particular tap or monitoring location outside the report period.
What to verify next
Continue Reading
Related explainers and report-reading guides
Read about topics related to Haloacetic acids (HAA5), or use a guide to understand the report as a whole.
Disinfection byproducts
Total trihalomethanes (TTHM)
TTHM is the defined sum of four trihalomethanes formed as disinfection byproducts. It is distinct from HAA5 and from the chlorine disinfectant.
Read the Total trihalomethanes (TTHM) contaminant guideHow to read a water quality report
A plain-English walkthrough of Consumer Confidence Reports, including report years, detected contaminants, legal limits, violations, and source notes.
View How to read a water quality reportDetection vs. violation vs. advisory
A careful guide to three different water-record terms, what each one can mean, and what official source to check next.
View Detection vs. violation vs. advisoryWhat public water data can and cannot tell you
What official public water records can help you check, what they cannot prove, and why missing data needs cautious interpretation.
View What public water data can and cannot tell you