Trichloroacetic Acid
TCAA·Affects liver, reproductive
One of the five haloacetic acids regulated as a group in chlorinated water. Typically the most abundant HAA in low-bromide municipal supplies.
TCAA
EPA limit
0.060 mg/L (combined HAA5)
Most at risk
Long-term consumers, pregnant women
Found in
City water
AquaOx filters
YesActivated coconut shell carbon
What it does to you
Health effects
Trichloroacetic acid (TCAA) is one of the five haloacetic acids regulated together by the EPA at 60 ppb (HAA5). The liver is the primary target organ in long-term studies, with hepatic enlargement and tumors observed at chronic high doses in animals.
Reproductive and developmental concerns are also documented. EPA references show adverse developmental outcomes in animal models, and the agency considers HAAs collectively a concern for pregnant women. Bladder cancer signals appear in some human epidemiology of long-term chlorinated-water consumers.
TCAA is non-volatile, so inhalation and dermal absorption during showers are not significant exposure routes. Ingestion through drinking and cooking water is what the regulation addresses.
Where it comes from
How it gets into your water
TCAA forms when chlorine reacts with naturally-occurring organic matter (humic and fulvic acids) during treatment. The same reaction produces dichloroacetic acid (DCAA) and the THMs; TCAA tends to be the most abundant HAA when source-water bromide is low.
The reaction continues in distribution pipes after the water leaves the plant, so TCAA can be higher at the end of the line. Warmer water and higher organic loads accelerate formation, which is why levels peak in late summer and early fall.
Chlorinated treatment plants
Chlorine reacts with organic matter
Distribution pipes
Reaction continues during transit
Tap water
Ingested in drinking and cooking water
Find out for yourself
Is it in your water?
TCAA is present in essentially every chlorinated US municipal supply, since the reaction that creates it is intrinsic to chlorine disinfection. Your utility's annual Consumer Confidence Report (CCR) reports total HAA5; the breakdown into individual species is sometimes included.
Concentrations rise seasonally with warmer water and higher organic content, and households at the periphery of the distribution network see the highest residuals.
The fix
How AquaOx filters it
Activated carbon adsorbs HAAs, including TCAA. The catalytic and coconut-shell carbon stages in AquaOx systems are designed to capture the HAA5 family at residential flow rates.
Because TCAA exposure is primarily through ingestion rather than shower vapor, the practical advantage of whole-house filtration is that every tap (kitchen, ice maker, coffee maker, formula-mixing station) delivers filtered water without the user having to remember which fixture is which.