ASHRAE Journal - April 2020 - 66

COLUMN HVAC APPLICATIONS

Controlling Legionella

Legionella bacteria inhabit all types and varieties of
water sources, including lakes, streams and groundwater6 (Figure 1a). Other types of bacteria like E. coli are
also present in these same sources, as are viruses like
norovirus and rotavirus, as well as parasites like Giardia
Lamblia7. The public expects that water treatment plants
adequately combine filtration and chemical treatment
to kill these and any other waterborne pathogens. This
trust, however, may be misplaced.
The Safe Drinking Water Act (SDWA) is the federal
law that governs water treatment to ensure it is safe for
human consumption. The National Primary Drinking
Water Regulations (NPDWR) are the standard for treating drinking water and are legally enforced by the EPA.
Yet, nationally, there's a concerning divergence between
theory and real accomplishment.
The EPA's NPDWR provides that 99.9% of the Giardia
parasite must be removed or inactivated from the
municipal supply. There is no stated limit, however,
for concentrations of Legionella. The expectation is that
the treatments to remove microbes like Giardia will also
result in the removal or inactivation of Legionella, but the
studies suggests otherwise.8 As the three studies demonstrate, the current municipal water treatment measures
are ineffective in neutralizing and inhibiting Legionella,
and instead allow various bacteria and other pathogens
to enter the distribution system and to pose health risks
to the public.
Also, the presence of Legionella without the presence of
other pathogens like Giardia demonstrates that although
treatment is effective for one pathogen, it does not eliminate Legionella, as assumed in the EPA's National Primary
Drinking Water Regulations.

Recommendations

The key takeaway is that it is imperative that the
National Primary Drinking Water Regulations be revised
to require testing for Legionella bacteria and also require
remedial actions as needed. Federal regulations must be
modified to ensure that Legionella bacteria is dealt with
at the water treatment plant and through the water distribution system, rather than making it the sole responsibility of the downstream users to remove and limit
the growth of Legionella bacteria. These measures would
then complement targeted downstream efforts to curb
Legionella growth, such as ensuring that disinfectants

66

ASHRAE JOURNAL

ashrae.org

APRI L 2020

are at proper levels when the water is entering the
buildings.
There are new statewide efforts that represent good
examples of how this could work in practice. For example, Illinois recently modified their EPA regulations
to include raising residual chlorine levels to ensure a
continuing antimicrobial effort as the water makes its
way through the system. The same regulations require
water turnover in storage tanks to address stagnation,
and the elimination of dead ends in water distribution
systems. Louisiana and Pennsylvania have passed similar measures, and New Jersey is considering joining
this group. These efforts must be supplemented with
effective measures at the municipal water treatment
facilities to remove Legionella further upstream, closer
to the source.
All the studies mentioned in this column support the
fact that Legionella bacteria are widespread, and if not
controlled will result in greater numbers of Legionellarelated cases and outbreaks. Therefore, a focus on
efforts to better control pathogens in the public water
supply upstream by strengthening EPA requirements is
the rational approach to addressing the increased threat
of waterborne pathogenic bacteria-related disease cases
in the future.

References

1. Lu, J, Struewing I, Yelton S, Ashbolt N. 2015. "Molecular survey
of occurrence and quantity of Legionella spp., Mycobacterium spp.,
Pseudomonas aeruginosa and amoeba hosts in municipal drinking
water storage tank sediments." Journal of Applied Microbiology
119(1):278-88.
2. Donohue, M., et al. 2014. "Widespread molecular detection of
Legionella pneumophila serogroup 1 in cold water taps across the
United States." Environmental Science and Technology 48(6):3145 - 3152.
3. Llewellyn, A., et al. 2017. "Distribution of Legionella and
bacterial community composition among regionally diverse US
cooling towers." PLOS.
4. Hilborn, E.D., et al. 2013. "Surveillance for waterborne
disease outbreaks associated with drinking water and other
nonrecreational water-United States, 2009−2010." Morbidity and
Mortality Weekly Report 62(35):714 - 720.
5. Hlavsa, M.C., et al. 2014. "Recreational water-associated
disease outbreaks-United States, 2009−2010." Morbidity and Mortality
Weekly Report 63(1):6−10.
6. U.S. EPA. 2000. "Legionella: Drinking Water Fact Sheet." Office
of Water. U.S. Environmental Protection Agency.
7. U.S. EPA. 2000. "Giardia: Drinking Water
Fact Sheet." Office of Water. U.S. Environmental
Protection Agency.
8. U.S. EPA. 2009. "National Primary
Drinking Water Standards," EPA 816-F-09-004. https://bit.ly/2T2iToK
Rate This Column
U.S. Environmental Protection Agency.


https://www.bit.ly/2T2iToK https://www.ashrae.org/

ASHRAE Journal - April 2020

Table of Contents for the Digital Edition of ASHRAE Journal - April 2020

Contents
ASHRAE Journal - April 2020 - Intro
ASHRAE Journal - April 2020 - Cover1
ASHRAE Journal - April 2020 - Cover2
ASHRAE Journal - April 2020 - 1
ASHRAE Journal - April 2020 - Contents
ASHRAE Journal - April 2020 - 3
ASHRAE Journal - April 2020 - 4
ASHRAE Journal - April 2020 - 5
ASHRAE Journal - April 2020 - 6
ASHRAE Journal - April 2020 - 7
ASHRAE Journal - April 2020 - 8
ASHRAE Journal - April 2020 - 9
ASHRAE Journal - April 2020 - 10
ASHRAE Journal - April 2020 - 11
ASHRAE Journal - April 2020 - 12
ASHRAE Journal - April 2020 - 13
ASHRAE Journal - April 2020 - 14
ASHRAE Journal - April 2020 - 15
ASHRAE Journal - April 2020 - 16
ASHRAE Journal - April 2020 - 17
ASHRAE Journal - April 2020 - 18
ASHRAE Journal - April 2020 - 19
ASHRAE Journal - April 2020 - 20
ASHRAE Journal - April 2020 - 21
ASHRAE Journal - April 2020 - 22
ASHRAE Journal - April 2020 - 23
ASHRAE Journal - April 2020 - 24
ASHRAE Journal - April 2020 - 25
ASHRAE Journal - April 2020 - 26
ASHRAE Journal - April 2020 - 27
ASHRAE Journal - April 2020 - 28
ASHRAE Journal - April 2020 - 29
ASHRAE Journal - April 2020 - 30
ASHRAE Journal - April 2020 - 31
ASHRAE Journal - April 2020 - 32
ASHRAE Journal - April 2020 - 33
ASHRAE Journal - April 2020 - 34
ASHRAE Journal - April 2020 - 35
ASHRAE Journal - April 2020 - 36
ASHRAE Journal - April 2020 - 37
ASHRAE Journal - April 2020 - 38
ASHRAE Journal - April 2020 - 39
ASHRAE Journal - April 2020 - 40
ASHRAE Journal - April 2020 - 41
ASHRAE Journal - April 2020 - 42
ASHRAE Journal - April 2020 - 43
ASHRAE Journal - April 2020 - 44
ASHRAE Journal - April 2020 - 45
ASHRAE Journal - April 2020 - 46
ASHRAE Journal - April 2020 - 47
ASHRAE Journal - April 2020 - 48
ASHRAE Journal - April 2020 - 49
ASHRAE Journal - April 2020 - 50
ASHRAE Journal - April 2020 - 51
ASHRAE Journal - April 2020 - 52
ASHRAE Journal - April 2020 - 53
ASHRAE Journal - April 2020 - 54
ASHRAE Journal - April 2020 - 55
ASHRAE Journal - April 2020 - 56
ASHRAE Journal - April 2020 - 57
ASHRAE Journal - April 2020 - 58
ASHRAE Journal - April 2020 - 59
ASHRAE Journal - April 2020 - 60
ASHRAE Journal - April 2020 - 61
ASHRAE Journal - April 2020 - 62
ASHRAE Journal - April 2020 - 63
ASHRAE Journal - April 2020 - 64
ASHRAE Journal - April 2020 - 65
ASHRAE Journal - April 2020 - 66
ASHRAE Journal - April 2020 - 67
ASHRAE Journal - April 2020 - 68
ASHRAE Journal - April 2020 - 69
ASHRAE Journal - April 2020 - 70
ASHRAE Journal - April 2020 - 71
ASHRAE Journal - April 2020 - 72
ASHRAE Journal - April 2020 - 73
ASHRAE Journal - April 2020 - 74
ASHRAE Journal - April 2020 - 75
ASHRAE Journal - April 2020 - 76
ASHRAE Journal - April 2020 - 77
ASHRAE Journal - April 2020 - 78
ASHRAE Journal - April 2020 - 79
ASHRAE Journal - April 2020 - 80
ASHRAE Journal - April 2020 - 81
ASHRAE Journal - April 2020 - 82
ASHRAE Journal - April 2020 - 83
ASHRAE Journal - April 2020 - 84
ASHRAE Journal - April 2020 - 85
ASHRAE Journal - April 2020 - 86
ASHRAE Journal - April 2020 - 87
ASHRAE Journal - April 2020 - 88
ASHRAE Journal - April 2020 - 89
ASHRAE Journal - April 2020 - 90
ASHRAE Journal - April 2020 - 91
ASHRAE Journal - April 2020 - 92
ASHRAE Journal - April 2020 - 93
ASHRAE Journal - April 2020 - 94
ASHRAE Journal - April 2020 - 95
ASHRAE Journal - April 2020 - 96
ASHRAE Journal - April 2020 - Cover3
ASHRAE Journal - April 2020 - Cover4
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_YELQLJ
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_QJLWMC
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_MCDEBX
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_WNYSQY
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_XATVOD
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_FJSHSS
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_CCBZDS
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_XDEFVG
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2023november_v2
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2023november
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_VHGNBL
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_WPKBNJ
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_UUVCDE
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_RTGDEW
https://www.nxtbook.com/nxtbooks/ashrae/ashraemexico_2023
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_LKRFXS
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_AZSOFG
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_ERCDBH
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_QWDFRV
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_JHGVDF
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_OPUYHG
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_SREIBM
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_LRTGLK
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_OKRFGH
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2022november_v2
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2022november
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_TZSERA
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_LVRUIX
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_RPTVYZ
https://www.nxtbook.com/nxtbooks/ashrae/mini_pub_catalog
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_XIYTGD
https://www.nxtbook.com/nxtbooks/ashrae/ashraemexico_2022
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_RFGDOB
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_PABXNU
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_REMKLS
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_PICVBT
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_AOYTVW
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_JQOPLS
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_IOYTBC
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_SGAJJF
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_IGHYER
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_PDRKLS
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2021november
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2021november_v2
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_XCODFR
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_QSLFGO
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_ILKVNM
https://www.nxtbook.com/nxtbooks/ashrae/ashraemexico_2021
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_OPDJKD
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_VJKSRY
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_SDHUTC
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_JPPKRR
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_SDLTTH
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_CKLLES
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_SLDOX
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_HJETUK
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_OLUHGE
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2020october
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2020october_v2
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_ZERDGH
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_QVMNEO
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_RTPOKE
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_BBATRE
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_STUBMW
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_TPEMPE
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_JNMKDS
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_FBTTPA
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_WQMMNE
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_TVBRYN
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_showguide2020
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_KTUZMA
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_ABEDGD
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201910
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201909
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2019septmeber_v2
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2019september
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201908
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201907
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201906
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201905
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201904
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_2019april
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201903
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_2019march
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201902
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201901
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_showguide2019
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_2018december
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_2018november
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2018fall_v2
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2018fall
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_2018october
https://www.nxtbook.com/nxtbooks/ashrae/ashraemexico_2018
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201810
https://www.nxtbook.com/nxtbooks/ashrae/ashraeinsights_201806
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201805
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201804
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201803
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201712
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201711
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201710
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2017fall_v2
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2017fall
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201709
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201705
https://www.nxtbook.com/nxtbooks/ashrae/ashrae_meetinginsert_201610
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2016fall_v2
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2016fall
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_acrexindia
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2015summer_v2
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2015summer
https://www.nxtbook.com/nxtbooks/amca/2014summer2
https://www.nxtbook.com/nxtbooks/amca/2014summer
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_acma_2014summer
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201311
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201309
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_acmasupp_2013fall
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201305
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201303
https://www.nxtbook.com/nxtbooks/ashrae/pubcatalog_2013winter
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201211
https://www.nxtbook.com/nxtbooks/ashrae/achr_expo_mexico2012
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201209
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201208_v3
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201208_v2
https://www.nxtbook.com/nxtbooks/ashrae/pubcatalog_2012summer
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201205
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201203
https://www.nxtbook.com/nxtbooks/ashrae/pubcatalog_2012winter
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201111_v2
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201109_v2
https://www.nxtbook.com/nxtbooks/ashrae/pubcatalog_2011summer
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201105
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201103
https://www.nxtbookmedia.com