Unintended Consequences of Chloramine Hit Home

Abstract

The known drawbacks of chloramination include nitrification, elastomer decay, and required pretreatment steps for fish culture and dialysis patients. To date, there has been no explicit consideration of adverse consequences of chloramination on property and water quality in buildings. Specifically, the effect of chloramine on re-growth of bacteria during stagnation, plumbing failures and lead leaching are poorly understood.Potential problems with bacterial re-growth can arise in building plumbing systems after chloramines decay and form free ammonia. Autotrophic nitrifying bacteria convert the free ammonia to nitrite and nitrate while creating organic carbon in the form of biomass and soluble microbial products. The levels of organic carbon created by nitrifiers are sufficient to support the growth of heterotrophic (HPC) bacteria. In one water tested with long stagnation times, HPC reached 10 6 -10 7 cfu/ml using chloramines, whereas HPC was 1000x less when chlorine disinfectant was used. The decay of chlorine does not release nutrients for bacterial growth-a significant advantage relative to chloramine in situations with low flow and long detention times. Because the water within home plumbing is rarely sampled for bacteria, the true extent of the problem is not detected by routine distribution system monitoring using flushed samples.A switch to chloramine may increase lead leaching, brass failures and pinhole leaks under at least some circumstances. Of these problems, pinhole leaks and brass failures have the largest potential economic consequence. For instance, a single re-plumb can cost an individual consumer 500x more than the median annual projected cost of the Stage 2 regulation. The adverse public health impacts of mold growth from pinhole leaks, lead leaching and bacterial re-growth deserve consideration. While these problems may eventually prove to be rare events, they have significant consequences for the unfortunate consumers who are impacted. If these events prove to be widespread, alternatives to chloramine will become more attractive despite higher initial cost to utilities.

Survey of green building water systems reveals elevated water age and water quality concerns

“…Although no direct quantification of biofilms was made, there were sometimes over 10 000 times more 16S rRNA genes in stagnant versus flushed samples, confirming significant levels of microbial activity in the stagnant pipes serving the taps compared to the water main. 47 It was previously thought that rapid residual decay is only rarely observed in buildings; 40,48 however, these results, in concert with Nguyen et al (2012), give rise to the concern it may be commonplace in premise plumbing with high water age. Overall, disinfectant residual decay rates in these buildings were 2-16 times greater than reported in previous work in a green plumbing system with a chloramine residual, for which serious problems with lead and consumer complaints of the taste and odor of the water had been reported.…”

Risk of Waterborne Illness Via Drinking Water in the United States

“…Pepper et al (2004) found that the bacteriological quality of water signifi cantly deteriorates in the home plumbing relative to the distribution system, as evidenced by survey of heterotrophic plate count (HPC) bacteria (Table 6). Stagnant water in premise plumbing provides an environment where bacteria can grow to values several orders of magnitude higher than in the municipal distribution system (Edwards et al 2005). Although HPC bacteria in drinking water is not considered a direct health risk (WHO/NSF 2003), opportunistic pathogens such as Legionella and Mycobacterium are associated with human disease and have been found in premise plumbing biofi lms (Flannery et al 2006;Pryor et al 2004;Thomas et al 2006;Tobin-D'Angelo et al 2004;Vacrewijck et al 2005).…”

Accelerated chloramine decay and microbial growth by nitrification in premise plumbing

“…All of these issues—including nitrification, chloramine decay rate, and increased HPCs—are expected to be especially significant under the frequent long stagnation conditions found in premise plumbing (Zhang et al, 2009; Edwards et al, 2005). Once established, nitrification in such situations might not be controlled, even at a high level of chloramine dosage.…”

“…The loss of chloramine is a possible concern in premise plumbing because it might allow for regrowth of Legionella in hot water heaters. Legionella , an opportunistic pathogen, has recently been identified as a major cause of waterborne disease outbreaks ( PM Engineer , 2008; Strickhouser, 2007; Edwards et al, 2005). Limited data collected to date strongly indicate that chloramine is usually far superior to free chlorine in terms of Legionella control because of the longer persistence of chloramine disinfectant in the absence of nitrification (Strickhouser, 2007; Flannery et al, 2006; DeGraca, 2005; Kool et al, 1999a, b).…”