Answers by Abbey Spring to frequently asked questions about chloramination.

What is Chloramination?

Marin Municipal Water District (MMWD) has historically chlorinated drinking water to disinfect against bacteria. As of April 1995, they will use a method called chloramination in the distribution system, in addition to chlorinating the water at the plant. Chloramination is the use of chlorine mixed with ammonia, to disinfect our drinking water. When chlorine and ammonia are combined, they form a new chemical complex called ‘chloramines.’ Chloramines are four times more stable than chlorine, and are valued for their residual effect in disinfecting drinking water. Although both are liquid gasses, chlorine evaporates out at a faster rate then chloramines. Although chloramines are not as potent as chlorine at killing bacteria, it will be enough to keep bacterial from growing in the pipes/distribution system, and will eliminate the need to add additional chlorine at the booster sites along the distribution pipes.

Why Chloramination?

Local municipalities have been mandated by the Environmental Protection Agency (EPA) to eliminate or reduce Trihalomethanes (THMs) from public water supplies to .1 part per million (ppm), or 100 parts per billion. Although MMWD’s THM content of .062-.08 parts per million does not exceed the current MCL (maximum contaminant level) for THMs, the EPA is expected to come out with a new MCL of .05 ppm. Chloramination will reduce the possibility of future occurrences of Trihalomethanes. It will also reduce the amount of chlorine used.

What are Trihalomethanes?

Trihalomethanes (THMs) are volatile organic chemicals (VOC) which are produced when chlorine interacts with organic material in the water (dead leaves, sediment, etc.) Various THMs have been classified by the EPA as either probable or possible human carcinogens, and have been associated with bladder and rectal cancer according to studies registered with the EPA and research performed by Dr. Robert Morris of the Medical College of Wisconsin, and others.

How Does Chlorine and Chloramines Kill Bacteria?

Chlorine does its job of killing bacteria by bonding with and oxidizing organic compounds in the water in a free radical process. Oxidation can occur with the proteins and organic matter inside and outside our bodies as well, and has been associated with cell damage and reduced cell vitality by many nutritionists. Chloramination will actually reduce the amount of chlorine needed, however little is known about the long term health effects of chloramines.

Chloramines are less potent than chlorine, but do their job of killing bacteria by breaking down or rupturing cell walls.

Because chloramines in high doses have been found to cause blood damage and liver damage in laboratory animals, the EPA has capped the allowable usage of chloramines at 4 ppm. MMWD will stay below that, adding about 1-2 ppm with a maximum of 2 ppm. Chloramine content will diminish slightly as it travels further from the source.

What side effects should I be concerned about?

Chloraminated water may cause fish to die, because fish take water directly into their bloodstream. Dialysis patients need to use treated water because water comes into direct contact with the bloodstream, and chloramines (like chlorine) are damaging to blood. Chloramination can also impact breweries and bakeries as yeast and enzymes may not survive.

How can I remove chloramines from my drinking water?

The combination of reverse osmosis and carbon filtration will be effective in removing chloramines. Chloramines are a little bit more stubborn that chlorine, and require a longer contact time (the time that water is in contact with the carbon media). Generally, a contact time provided by a flow rate of less than one gallon per minute will allow for thorough removal of chloramines. On a reverse osmosis system, because the rate of flow is slowed down to less than .05 gallons per minute (gpm), there is plenty of contact time for thorough removal.

Carbon filtration and granular activated carbon filtration alone can also be effective at removing chloramines if the flow rate is under 1 gpm. This would be the case in almost all circumstances for customers using the Abbey Spring’s dual and single filter assemblies. Under rare circumstances, the staff at Abbey Spring may recommend that you change your filters more frequently or add an additional carbon filter.

Will chloramination affect my present drinking water system?

No. Chloramines can foul thin film composite (TFC) membranes, just as chlorine can. However, if you have a TFC membrane, and you are on a municipal supply, you should currently have a pre-carbon filter (water goes through this filter before going across the membrane), to eliminate or reduce chlorine and chloramines. This will protect your membrane from corrosion or fouling. The longevity of membranes will not be affected nor will production rates.

Will my shower filter remove chloramines?

KDF, the media used in the shower filters sold by Abbey Spring will remove free chlorine. Because shower water is hot, most of the chloramines will break down into chlorine and ammonia, and be removed. The chlorine that remains bonded with ammonia (chloramine) is not vaporous, and cannot be absorbed by the skin or breathed into the lungs.