THMs are volatile organic compounds. That means they desire to release from the water into the air, similar to the way carbonation in a carbonated beverage such as soda or seltzer water releases into the air when you first open the bottle. The City of Napa performed a small experiment at the treatment facility and analyzed several samples after they had been handled the common ways a customer might fill a glass of water to drink it in their home. This is only one experiment, but shows the nature of the reduction of THMs.
Each entry below was handled as described, then poured into a sample bottle with no head space per analytical protocols and analyzed for THMs.
|FROM FAUCET DIRECT||87.6|
|FROM FAUCET INTO GLASS, SITTING FOR 5 MINUTES||67.7|
|FROM FAUCET THROUGH A BRITA FILTER||64.8|
|THROUGH A REFRIGERATOR FILTER||54.4||carbon filter for GE Model #PSC3RGXCFSS, Filter #WF282 GE MSWF|
|THROUGH AN INLINE FILTER UNDER THE SINK FROM FAUCET||2.7|
4 filter (GAC) R/O system, Sierra Model NS-1N30-00 by Nimbus Water Systems
Note this is one side by side study employing standard laboratory sample techniques. The City of Napa does not recommend one filter manufacturer over another, nor does it guarantee the effectiveness of any home filter devices. All home water filter systems need regular maintenance to operate effectively. The effectiveness of filter brands is tested by the National Science Foundation (NSF). For specific information about your filter, contact the manufacturer.