Haloacetic Acids (HAA5) in Drinking Water
EPA limits, health effects, and what to do if your water is affected.
🩨 Health Effects
Five haloacetic acids that form as byproducts of chlorination, similar to TTHMs. Long-term exposure is associated with increased cancer risk. Some studies suggest reproductive effects at high levels.
📍 Sources in Water
Formed during water chlorination when chlorine reacts with organic matter. Levels vary seasonally, are higher in summer, and are highest in systems treating surface water with high organic content.
✅ What To Do
Activated carbon filters and reverse osmosis can reduce HAA5 levels. Point-of-use filters at the kitchen tap are practical. Check your Consumer Confidence Report for annual average levels.
Check your tap water for Haloacetic Acids (HAA5)
Search your ZIP code to see if your water system has had Haloacetic Acids (HAA5) violations, plus lead testing results and an overall safety grade.
Search your ZIP code →Data from the EPA's Safe Drinking Water Information System (SDWIS). MCLs reflect minimum federal standards; some contaminants may pose health risks below these thresholds.