Chloramine water disinfection:

This article explains the use of chloramines, a secondary disinfectant used to treat drinking water.

Chloramine disinfectants are used to treat drinking water because of the ability of these chemicals to provide longer-lasting disinfection of drinking water as it moves through water mains and piping between the community water source and the end-using water consumer.

Chloramine Treatment of Drinking Water

This series of articles explains many common water contamination tests for bacteria and other contaminants in water samples. We describe what to do about contaminated water, listing common corrective measures when water test results are unsatisfactory.

We include water testing and water correction measures warnings for home owners and especially for home buyers when certain conditions are encountered, with advice about what to do when these circumstances are encountered.

Our photo (above) shows common slime formation inside of a garden hose. Similar slime layers may form inside of water pipes where water is not treated for its prevention.

[Click to enlarge any image]

U.S. EPA Information on Chloramines in Drinking Water

Chloramines in Drinking Water used as disinfectants: ammonia + chlorine

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.

The Environmental Protection Agency regulates the safe use of chloramines in drinking water.³

• EPA requires water utilities to meet strict health standards when using chloramines to treat water.
• EPA chloramines regulations are based on the average concentration of chloramines found in a water system over time.
• EPA regulates certain chemicals formed when chloramines react with natural organic matter⁴ in water.

Additional Supporting Information Concerning the Use of Chloramines in Drinking Water

1. Dichloramine is formed when the chlorine to ammonia-nitrogen weight ratio is greater than 5:1, however, this reaction is very slow. Organic chloramines are formed when chlorine reacts with organic nitrogen compounds. Source: Optimizing Chloramine Treatment, 2nd Edition, AwwaRF, 2004
2. Trichloramine formation does not usually occur under normal drinking water treatment conditions. However, if the pH is lowered below 4.4 or the chlorine to ammonia-nitrogen weight ratio becomes greater than 7.6:1, then trichloramine can form. Trichloramine formation can occur at a pH between 7 and 8 if the chlorine to ammonia-nitrogen weight ratio is increased to 15:1. Source: Optimizing Chloramine Treatment, 2nd Edition, AwwaRF, 2004
3. The drinking water standard for chloramines is 4 parts per million (ppm) measured as an annual average. More information on water utility use of chloramines is available at http://www.epa.gov/safewater/disinfection/index.html and in the 1997-1998 Information Collection Rule, a national survey of large drinking water utilities for the Stage 2 Disinfection Byproducts Rule (DBPR).
   
   Information on the Stage 2 DBPR is available at http://www.epa.gov/safewater/disinfection/stage2/.
   More information on EPA’s standard setting process may be found at: http://www.epa.gov/OGWDW/standard/setting.html.
4. Natural Organic Matter: Complex organic compounds that are formed from decomposing plant, animal and microbial material in soil and water. They can react with disinfectants to form disinfection by products. Total organic carbon (TOC) is often measured as an indicator of natural organic matter.

-- Chloramines in Drinking Water, U.S. Environmental Protection Agency

Public Concerns Regarding Use of Chloramines

Quoting from Drinking Water Issues: Chloramine, U.S. Environmental Protection Agency:

Recently San Francisco Public Utility Commision (SFPUC - http://www.sfwater.org )changed from using free chlorine to chloramine in its drinking water transmission pipes. Some people are concerned for possible public health implications and for reported effects on fish and amphibians.

Using chloramine to disinfect drinking water is a common standard practice among drinking water utilities. A number of utilities have made this switch from chlorine to chloramines to enhance water safety and compliance with drinking water health standards. For example, the East Bay Municipal Utility District (EBMUD - http://www.ebmud.com/), which serves drinking water to customers in parts of the greater San Francisco Bay area, switched from chlorine to using chloramine in February, 1998.

Background information on chloramines

Chlorine has been safely used for more than 100 years for disinfection of drinking water to protect public health from diseases which are caused by bacteria, viruses and other disease causing organisms. Chloramines, the monochloramine form in particular, have also been used as a disinfectant since the 1930's.

Chloramines are produced by combining chlorine and ammonia. While obviously toxic at high levels, neither pose health concerns to humans at the levels used for drinking water disinfection.

Chloramines are weaker disinfectants than chlorine, but are more stable, thus extending disinfectant benefits throughout a water utility's distribution system. They are not used as the primary disinfectant for your water. Chloramines are used for maintaining a disinfectant residual in the distribution system so that disinfected drinking water is kept safe. Chloramine can also provide the following benefits:

• Since chloramines are not as reactive as chlorine with organic material in water, they produce substantially lower concentrations of disinfection byproducts in the distribution system. Some disinfection byproducts, such as the trihalomethanes (THMs) and haloacetic acids (HAAs), may have adverse health effects at high levels. These disinfection byproducts are closely regulated by EPA. EPA recently reduced the allowable Maximum Contaminant Levels for total THMs to 80 ug/L and now limit HAAs to 60 ug/L.
  
  The use of chlorine and chloramines is also regulated by the EPA. We have Maximum Residual Disinfectant Levels of 4.0 mg/L for both these disinfectants. However, our concern is not from their toxicity, but to assure adequate control of the disinfection byproducts.
• Because the chloramine residual is more stable and longer lasting than free chlorine, it provides better protection against bacterial regrowth in systems with large storage tanks and dead-end water mains.
• Chloramine, like chlorine, is effective in controlling biofilm, which is a slime coating in the pipe caused by bacteria. Controlling biofilms also tends to reduce coliform bacteria concentrations and biofilm-induced corrosion of pipes.
• Because chloramine does not tend to react with organic compounds, many systems will experience less incidence of taste and odor complaints when using chloramine.

Other concerns with chloramines in drinking water

Chloramines, like chlorine, are toxic to fish and amphibians at levels used for drinking water. Unlike chlorine, chloramines do not rapidly dissipate on standing. Neither do they dissipate by boiling. Fish owners must neutralize or remove chloramines from water used in aquariums or ponds.

Treatment products are readily available at aquarium supply stores. Chloramines react with certain types of rubber hoses and gaskets, such as those on washing machines and hot water heaters. Black or greasy particles may appear as these materials degrade. Replacement materials are commonly available at hardware and plumber supply stores.

- Source: Drinking Water Issues: Chloramine, U.S. Environmental Protection Agency,

Thanks to reader Frank A. Marshall, AIA, LEED AP, at SMB&R, an Architecture, Structural Engineering, Interior Design firm in Camp Hill, PA for suggesting the addition of Chloramine drinking water treatment information

Basic water purification procedures that can be used in an emergency areat DRINKING WATER - EMERGENCY PURIFICATION. If community or private wells are back in operating and providing water, do not assume that the water is sanitary and ok to drink until responsible authorities have said so.

Even then, local water pipes in a building may be unsanitary and additional cleaning or disinfection may be needed.

See WELL CHLORINATION SHOCKING PROCEDURE and see WATER TESTS for CONTAMINANTS for advice on using a private well for drinking water.

Tests for Chloramine in Water

Chloramine testing is provided by a variety of laboratories, including companies who provide tests used by aquarium enthusiasts (chloramine at sufficient concentration and depending on the pH of the water, can injure fish).

Before becoming too worried, note that as with any chemical, "the dose makes the poison", and we undestand that Chloramine-T is under study as a treatment to kill bacteria and parasites in koi fish ponds.

Sources for Kits or Equipment for Chloramine Tests in Water

Because chloramine remains stable for a longer period in water, and because (sticking around longer) that may permit chlorine molecules to bond with other materials, different tests may be appropriate. A test kit that you intend to use to screen water for chlorine should include a test for "total chlorine" not just "free chlorine" because of this binding problem.

• Aquarium suppliers sell chlorine test kits that can detect chloramine in water.
• Chlorine/Chloramine Test Kits produced by Ecological Laboratories are sold through Amazon and at other outlets.
  [Disclosure: Amazon pays us a pittance for readers who buy from the above links]
• Chloramine Test Kits are sold at Amazon, but you should check online fdor a supplier and price that you like.
  [Disclosure: Amazon pays us a pittance for readers who buy from the above links]
• Local water testing labs in your area may also offer these tests as they are quite simple to perform.

Prices for these tests typically run from under $8.00 to $15.00.

Chlorine in water is tested for as hypochlorite (Cl₂O₂) (bleach solution). We discuss chlorine testing at CHLORINE TESTS, WATER, where we detail our procedure to test well water for trace levels of chlorine.

Also see WATER TREATMENT EQUIPMENT CHOICES and CHLORINATORS & CHARCOAL FILTERS.

Also see DRINKING WATER EMERGENCY PURIFICATION for a discussion of various methods used to purify emergency drinking water.

Reader Comment: home inspector concerned with chloramine-treated water

Independent House Diagnosis said:

HomeInspectors may wish to consider informing new end-users of houses receiving chloraminated water. Possible human and building effects are discussed at website of CCAC. For those who would call that inforamtion anecdotal I refer you to the book POISON SPRING , written by a 25 year EPA veteran. EPA is as behind on most issues as the entire world "health" community was on tobacco and asbestos and for similar reasons. - 2015/12/28

Reply:

Thanks for the book suggestion, HI. Below I've added links to find at Amazon.com both Valliantos' Poison Spring as well as Rachel Carson's famous Silent Spring in the Chloramine references above.

Chloramine Disinfectant Water Treatment Effectiveness & Chloramine in Drinking Water Research

• Also see citations atReferences or Citations
• Brodtmann Jr, Noel V., and Peter J. Russo. "The use of chloramine for reduction of trihalomethanes and disinfection of drinking water." Journal (American Water Works Association) (1979): 40-42.
• Carson Rachel, Silent spring . Houghton Mifflin Harcourt; 2002
• Carson, Rachel. "Silent Spring. 1962." (1994).
• Charrois, Jeffrey WA, and Steve E. Hrudey. "Breakpoint chlorination and free-chlorine contact time: Implications for drinking water N-nitrosodimethylamine concentrations." Water Research 41, no. 3 (2007): 674-682.
  Abstract:
  
  North American drinking water utilities are increasingly incorporating alternative disinfectants, such as chloramines, in order to comply with disinfection by-product (DBP) regulations. N-Nitrosodimethylamine (NDMA) is a non-halogenated DBP, associated with chloramination, having a drinking water unit risk two to three orders of magnitude greater than currently regulated halogenated DBPs. We quantified NDMA from two full-scale chloraminating water treatment plants in Alberta between 2003 and 2005 as well as conducted bench-scale chloramination/breakpoint experiments to assess NDMA formation.
  
  Distribution system NDMA concentrations varied and tended to increase with increasing distribution residence time. Bench-scale disinfection experiments resulted in peak NDMA production near the theoretical monochloramine maximum in the sub-breakpoint region of the disinfection curve.
  
  Breakpoints for the raw and partially treated waters tested ranged from 1.9:1 to 2.4:1 (Cl2:total NH3-N, M:M). Bench-scale experiments with free-chlorine contact (2 h) before chloramination resulted in significant reductions in NDMA formation (up to 93%) compared to no free-chlorine contact time. Risk-tradeoff issues involving alternative disinfection methods and unregulated DBPs, such as NDMA, are emerging as a major water quality and public health information gap.
• Coventry, F. L., V. E. Shelford, and L. F. Miller. "The conditioning of a chloramine treated water supply for biological purposes." Ecology 16, no. 1 (1935): 60-66.
• Glaze, William H. "Drinking-water treatment with ozone." Environmental science & technology 21, no. 3 (1987): 224-230.
• Kim, B. R., J. E. Anderson, S. A. Mueller, W. A. Gaines, and A. M. Kendall. "Literature review—efficacy of various disinfectants against Legionella in water systems." Water Research 36, no. 18 (2002): 4433-4444.
• LeChevallier, Mark W., Nancy J. Welch, and Darrell B. Smith. "Full-scale studies of factors related to coliform regrowth in drinking water." Applied and Environmental Microbiology 62, no. 7 (1996): 2201-2211.
  Abstract:
  
  An 18-month survey of 31 water systems in North America was conducted to determine the factors that contribute to the occurrence of coliform bacteria in drinking water. The survey included analysis of assimilable organic carbon (AOC), coliforms, disinfectant residuals, and operational parameters. Coliform bacteria were detected in 27.8% of the 2-week sampling periods and were associated with the following factors: filtration, temperature, disinfectant type and disinfectant level, AOC level, corrosion control, and operational characteristics.
  
  Four systems in the study that used unfiltered surface water accounted for 26.6% of the total number of bacterial samples collected but 64.3% (1,013 of 1,576) of the positive coliform samples. The occurrence of coliform bacteria was significantly higher when water temperatures were > 15 degrees C
  
  . For filtered systems that used free chlorine, 0.97% of 33,196 samples contained coliform bacteria, while 0.51% of 35,159 samples from chloraminated systems contained coliform bacteria.
  
  The average density of coliform bacteria was 35 times higher in free-chlorinated systems than in chloraminated water (0.60 CFU/100 ml for free-chlorinated water compared with 0.017 CFU/100 ml for chloraminated water). Systems that maintained dead-end free chlorine levels of < 0.2 mg/liter or monochloramine levels of < 0.5 mg/liter had substantially more coliform occurrences than systems that maintained higher disinfectant residuals. Free-chlorinated systems with AOC levels greater than 100 micrograms/liter had 82% more coliform-positive samples and 19 times higher coliform levels than free-chlorinated systems with average AOC levels less than 99 micrograms/liter.
  
  Systems that maintained a phosphate-based corrosion inhibitor and limited the amount of unlined cast iron pipe had fewer coliform bacteria.
  
  Several operational characteristics of the treatment process or the distribution system were also associated with increased rates of coliform occurrence. The study concludes that the occurrence of coliform bacteria within a distribution system is dependent upon a complex interaction of chemical, physical, operational, and engineering parameters. No one factor could account for all of the coliform occurrences, and one must consider all of the parameters described above in devising a solution to the regrowth problem.
• Regan, John M., Gregory W. Harrington, and Daniel R. Noguera. "Ammonia-and nitrite-oxidizing bacterial communities in a pilot-scale chloraminated drinking water distribution system." Applied and Environmental Microbiology 68, no. 1 (2002): 73-81.
• Reynolds, Kelly A., Kristina D. Mena, and Charles P. Gerba. "Risk of waterborne illness via drinking water in the United States." In Reviews of environmental contamination and toxicology, pp. 117-158. Springer New York, 2008.
• Richardson, Susan D., Michael J. Plewa, Elizabeth D. Wagner, Rita Schoeny, and David M. DeMarini. "Occurrence, genotoxicity, and carcinogenicity of regulated and emerging disinfection by-products in drinking water: a review and roadmap for research." Mutation Research/Reviews in Mutation Research 636, no. 1 (2007): 178-242.
• Richardson, S. D., A. D. Thruston Jr, T. V. Caughran, P. H. Chen, T. W. Collette, K. M. Schenck, B. W. Lykins Jr, Ch Rav-Acha, and V. Glezer. "Identification of new drinking water disinfection by-products from ozone, chlorine dioxide, chloramine, and chlorine." In Environmental Challenges, pp. 95-102. Springer Netherlands, 2000.
  Abstract
  
  Many drinking water treatment plants are currently using alternative disinfectants to treat drinking water, with ozone, chlorine dioxide, and chloramine being the most popular. However, compared to chlorine, which has been much more widely studied, there is little information about the disinfection by-products (DBPs) that these alternative disinfectants produce. Thus, it is not known if the DBPs from alternative disinfectants are safer or more hazardous than those formed by chlorine. To answer this question, we have set out to comprehensively identify DBPs formed by these alternative disinfectants, as well as by chlorine.
  
  The results presented here represent a compilation of the last 8 years of our research in identifying new DBPs from ozone, chlorine dioxide, chloramine, and chlorine. We also include results from recent studies of Israel drinking water disinfected with both chlorine dioxide and chloramine. Over 200 DBPs were identified, many of which have never been reported. In comparing by-products formed by the different disinfectants, ozone, chlorine dioxide, and chloramine formed fewer halogenated DBPs than chlorine.
• Stewart, Mic H., Roy L. Wolfe, and Edward G. Means. "Assessment of the bacteriological activity associated with granular activated carbon treatment of drinking water." Applied and environmental microbiology 56, no. 12 (1990): 3822-382
  Abstract:
  
  Bacteriological analyses were performed on the effluent from a conventional water treatment pilot plant in which granular activated carbon (GAC) had been used as the final process to assess the impact of GAC on the microbial quality of the water produced. Samples were collected twice weekly for 160 days from the effluents of six GAC columns, each of which used one of four different empty-bed contact times (7.5, 15, 30, and 60 min). The samples were analyzed for heterotrophic plate counts and total coliforms.
  
  Effluent samples were also exposed to chloramines and free chlorine for 60 min (pH 8.2, 23 degrees C). Bacterial identifications were performed on the disinfected and nondisinfected effluents. Additional studies were conducted to assess the bacteriological activity associated with released GAC particles. The results indicated that heterotrophic plate counts in the effluents from all columns increased to 10(5) CFU/ml within 5 days and subsequently stabilized at 10(4) CFU/ml. The heterotrophic plate counts did not differ at different empty-bed contact times.
  
  Coliforms (identified as Enterobacter spp.) were recovered from the nondisinfected effluent on only two occasions. The disinfection results indicated that 1.5 mg of chloramines per liter inactivated approximately 50% more bacteria than did 1.0 mg of free chlorine per liter after 1 h of contact time. Chloramines and chlorine selected for the development of different bacterial species--Pseudomonas spp. and Flavobacterium spp., respectively. (ABSTRACT TRUNCATED AT 250 WORDS
• Vallianatos, Evaggelos G., and McKay Jenkins. Poison Spring: The Secret History of Pollution and the EPA. Bloomsbury Publishing USA, 2014.
• Williams, David T., Guy L. LeBel, and Frank M. Benoit. "Disinfection by-products in Canadian drinking water." Chemosphere 34, no. 2 (1997): 299-316.

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In addition to any citations in the article above, a full list is available on request.

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