Chloramine or NH2Cl is commonly used in low concentrations as a secondary disinfectant in municipal water distribution systems as an alternative to free chlorine chlorination. This application is increasing. Chlorine ,sometimes referred to as free chlorine),is being displaced by chloramine, which is much more stable and does not dissipate from the water before it reaches consumers. NH2Cl also has a very much lower, however still present, tendency than free chlorine to convert organic materials into chlorocarbons such as chloroform and carbon tetrachloride. Such compounds have been identified as carcinogens and in 1979 the United States Environmental Protection Agency began regulating their levels in U.S. drinking water. Furthermore, water treated with chloramine lacks the distinct chlorine odour of the gaseous treatment and so has improved taste. In swimming pools, chloramines are formed by the reaction of free chlorine with organic substances.
Chloramines, compared to free chlorine, are both less effective as a sanitizer and more irritating to the eyes of swimmers. When swimmers complain of eye irritation from “too much chlorine” in a pool, the problem is typically a high level of chloramines.Pool test kits designed for use by homeowners are sensitive to both free chlorine and chloramines, which can be misleading.
Chloramines are disinfectants used to treat drinking water. Chloramines are most commonly formed when ammonia is added to chlorine to treat drinking water. The typical purpose of chloramines is to provide longer-lasting water treatment as the water moves through pipes to consumers. This type of disinfection is known as secondary disinfection. Chloramines have been used by water utilities for almost 90 years, and their use is closely regulated. More than one in five Americans uses drinking water treated with chloramines. Water that contains chloramines and meets EPA regulatory standards is safe to use for drinking, cooking, bathing and other household uses.
Many utilities use chlorine as their secondary disinfectant; however, in recent years, some of them changed their secondary disinfectant to chloramines to meet disinfection byproduct regulations. In order to address questions that have been raised by consumers about this switch, EPA scientists and experts have answered 29 of the most frequently asked questions about chloramines. We have also worked with a risk communication expert to help us organize complex information and make it easier for us to express current knowledge.
The question and answer format takes a step-wise approach to communicate complex information to a wide variety of consumers who may have different educational backgrounds or interest in this topic. Each question is answered by three key responses, which are written at an approximately sixth grade reading level. In turn, each key response is supported by three more detailed pieces of information, which are written at an approximately 12th grade reading level. More complex information is provided in the Additional Supporting Information section, which includes links to documents and resources that provide additional technical information.
EPA continues to research drinking water disinfectants and expects to periodically evaluate and possibly update the questions and answers about chloramines when new information becomes available.
Chloramine-treated water has a greenish cast, the source of the colour is uncertain. Pure water by contrast normally is bluish. This greenish color may be observed by filling a white polyethylene bucket with chloraminated tap water and comparing it to chloramine-free water such as distilled water or a sample from a swimming pool.
Adding chloramine to the water supply can increase exposure to lead in drinking water, especially in areas with older housing; this exposure can result in increased lead levels in the bloodstream and can pose a significant health risk.
There is also evidence that exposure to chloramine can contribute to respiratory problems, including asthma, among swimmers.Respiratory problems related to chloramine exposure are common and prevalent among competitive swimmers.
Chloramine use, together with chlorine dioxide, ozone, and ultraviolet, has been described as a public health concern and an example of the outcome of poorly implemented environmental regulation. These methods of disinfection decrease the formation of regulated byproducts, which has led to their widespread use. However, they can increase the formation of a number of unregulated byproducts, some of which pose greater health risks than the regulated chemicals.
Many animals are sensitive to chloramine and it must be removed from water given to many animals in zoos. Aquarium owners remove the chloramine from their tap water because it is toxic to fish. Aging the water for a few days removes chlorine but not the more stable chloramine, which can be neutralised using products available at pet stores.
Chloramine must also be removed from the water prior to use in kidney dialysis machines, as it would come in contact with the bloodstream across a permeable membrane. However, since chloramine is neutralized by the digestive process, kidney dialysis patients can still safely drink chloramine-treated water.
Home brewers use reducing agents such as sodium metabisulfite or potassium metabisulfite to remove chloramine from brewing liquor as it, unlike chlorine, cannot be removed by boiling . Residual sodium can cause off flavors in beer so potassium metabisulfite is preferred.
Chloramine cannot be removed from water by boiling, distilling or reverse osmosis, which at least helps to narrow your options! Beware of any company trying to sell you one of these as they simply don’t work.
The best method, and recommended by the US EPA, is an activated carbon block system. The very best will use a twin or multi-stage process with sub micron filtering and ion exchange for the best results. These can remove chloramine from water at a rate of 99.9%, and also the same removal rate for lead, pesticides, prescription drugs and all the other contaminants.