Haloacetic Acids in Shower Water: Health Effects & How to Remove It (2026)

Haloacetic Acids in Shower Water: Health Effects & How to Remove It (2026)

Haloacetic Acids in Shower Water: Health Effects & How to Remove It (2026)

Last updated: April 2026.

Haloacetic Acids in Shower Water

Understanding what's in your shower water and how it affects your health

What Is It & How Does It Get Into Water?

Haloacetic acids (HAAs) form when chlorine reacts with organic matter in water. Like THMs, they are classified as probable human carcinogens.

HAAs form alongside THMs during disinfection. The EPA regulates five (HAA5), while nine total (HAA9) exist. Levels increase with warmth and organic content.

Health Effects From Shower Exposure

⚠️ Shower-Specific Risks

Shower exposure is particularly significant because you absorb contaminants through skin absorption, inhalation of steam, and direct contact with eyes and mucous membranes during a typical 10-minute shower.

  • Skin absorption: HAAs penetrate skin during showering, adding to body burden
  • More stable: Less volatile than THMs but more persistent in water
  • Cancer risk: Several HAAs are classified as probable carcinogens
  • Skin irritation: As acids, HAAs can irritate sensitive skin and disrupt pH

Regulatory Standards & Health Guidelines

EPA vs EWG: The Gap Between Legal and Healthy

Standard Level
EPA Maximum Contaminant Level (MCL) 60 ppb for HAA5
EWG Health Guideline 0.06 ppb for HAA9 (1000x stricter than EPA)

Detected in NYC water at levels far exceeding health guidelines despite being within federal limits.

Filtration Methods That Remove It

Method Effectiveness Notes
Activated Carbon Up to 95% Effective for most HAAs
KDF-55 Media Moderate Complementary to carbon
Ion Exchange Up to 90% For ionized HAAs

How Afina Shower Filtration Can Help

Afina's multi-stage filtration system uses activated carbon and KDF-55 media to reduce chlorine, heavy metals, and other contaminants — helping protect your skin, hair, and overall health.

Filtered Showerhead

$99

Built-in multi-stage filtration

Shop Now

Shower Filter

$47

Fits any existing showerhead

Shop Now

Replacement Filter

$29

2-3 month filter life

Shop Now

Cities Most Affected

While this contaminant can be found in water systems nationwide, these areas tend to have higher levels:

Check your local water quality at the EWG Tap Water Database by entering your zip code.

Related Reading

Frequently Asked Questions

What are HAAs?

Cancer-linked chemicals forming when disinfectants react with organic matter. Found in virtually all chlorine-treated water.

Are HAAs dangerous in showers?

Classified as probable carcinogens. While less volatile than THMs, they absorb through skin during showering.

Do shower filters remove HAAs?

Carbon filters remove significant HAAs. Multi-stage filters with carbon + KDF offer best protection.

HAAs vs THMs?

Both are disinfection byproducts. THMs are more volatile (vaporize in steam), HAAs are more stable in water. Both are cancer-linked.

Ready to Upgrade Your Shower Water?

Join thousands of households that have switched to filtered shower water for healthier skin and hair.

Shop Filtered Showerhead Shop Shower Filter
Back to blog

You May Also Like