Addressing Contamination of Drinking Water
Distribution Systems from Volatile Organic
Compounds (VOCs) After Wildfires
After the 2017 Tubbs Fire and the 2018 Camp Fire In
California, volatile organic compounds (VOCs) were found
in the drinking water of the impacted towns. "Tests of
the water revealed elevated levels of several VOCs, such
as benzene, in water mains, service connections, and
building fixtures. If unaddressed, VOC contamination can
pose a potential health risk for consumers and result in a
loss of consumer confidence.
Addressing VOC contamination can be a potentially
long-term problem. Flushing is the primary method for
removing VOC contamination; however, flushing may not
always be effective or feasible. Infrastructure replacement
is another option, but depending on the scale, can
take time and be cost-prohibitive. Delays in addressing
contamination can impact the return of residents to
their homes and the restart of commercial businesses,
significantly slowing community recovery. This fact sheet
examines VOC drinking water contamination from the
Tubbs and Camp Fires and recommends practices to
assist drinking water utilities in identifying and addressing
contamination. While this information is intended for
public water systems, it also may benefit private water
systems and well owners.
The causes and remediation of VOC
contamination in distribution systems is an
emerging field of study. The cited research
reflects the current understanding of wildfire
impacts on drinking water distribution
systems as well as the informational
gaps. This document is meant to provide
a resource for water utilities, communities,
and state primacy agencies dealing with
wildfire damage and public health concerns.
Utilities should contact their state primacy
agency or EPA Regional Office for additional
technical assistance.
Wildfire VOC Contamination
VOC contamination may occur when water distribution infrastructure (e.g., pipes, valves, meters, etc.) is
impacted by a wildfire. VOC contamination has been observed primarily in areas that were damaged during
the wildfire and experienced pressure loss in the water system. Research into the exact cause of the VOC
contamination is ongoing, but two possible explanations have been proposed that may account for such
contamination either alone or in combination.
1. Contamination may be released into the water from infrastructure containing polyvinyl chloride
(PVC), high density polyethylene (FIDPE), or other plastic materials that degrade when exposed
to heat.1
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2. Contamination may occur when the smoke,
hot gases, and chemicals (e.g., VOCs)
from burning vegetation and structures are
sucked into the water lines. This suction
can occur when the water pressure drops
due to broken water lines or water demand
elsewhere in the system.2
Whatever the source, VOC contaminated water can
potentially be moved to parts of the water system
unimpacted by the wildfire.
An additional challenge is that VOCs can permeate
into some materials (e.g., certain plastics, such
as polyethylene, and rubber).3 The VOCs then can
be released back into the water. While the release
of VOCs from these materials is slow, VOCs can accumulate in the water, particularly under stagnant
conditions when the water remains in contact with contaminated material for an extended period. The
potential for recoti lamina lion of the water will persist until all the VOC contamination has leached out
VOC contamination can be present without visible damage, as infrastructure (e.g., pipes, meters) in the
impacted area may retain the ability to sustain pressure and flow following a fire. The only way to determine
if the water has elevated levels of VOCs is to collect water samples for analysis.
Analytical testing from impacted communities demonstrated that VOC concentrations at service
connections can exceed the Safe Drinking Water Act maximum contaminant levels (MCLs) In some cases,
residents were advised not to drink, cook, or bathe with the water. 4<5
Testing for Contamination - Sampling and Analysis
To determine if contamination is present, water systems should create a sampling plan with their state
regulatory agency that identifies target contaminants, sample collection protocols, sampling locations
(in the distribution system and surviving buildings), and data quality and management. The plan should
account for a potentially large number of samples that could be collected over an extended period (e.g.,
months) depending on the extent of fire damage and if contamination is found.
Target Contaminants Multiple VOCs, both regulated and unregulated, may be present in contaminated
water. At present, it is unclear which chemicals are of most concern following a wildfire. Benzene was found
in many of the samples collected during the Tubbs and Camp Fires2; however, it is not a perfect indicator
of VOC contamination as some water samples that were free of benzene contained other VOCs. Because
knowledge is limited on the types of contaminants that may impact drinking water distribution systems
during wildfires, utilities should consider broader methods, such as EPA methods 502.2 or 524.2, that
cover a range of contaminants potentially associated with fire impacts. Utilities should also consider that
chemicals not covered by these methods may be present. Utilities should contact their state regulatory
agency or EPA Regional Office to discuss additional methods for specific contaminants of interest.
Degraded plastic pipe following wildfire
Credit: CA State Water Board Division of Drinking Water
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Sample Collection Protocols: The protocol for sample collection is critical for determining the presence
and extent of contamination. As noted above, because VOCs can leach out of some materials over time,
a period of stagnation should be incorporated into the sampling protocol. A stagnation period should be
established that best assures the presence or absence of contamination while also taking feasibility into
consideration. Stagnation periods of 8, 24, 48, and 72 hours have been suggested during past wildfires,
with longer periods allowing larger guantities of the contaminants to enter the water, thus increasing the
likelihood of detection during analysis and providing greater confidence in the results. Additionally, the
utility should consider multiple samples (e.g., first draw and then a second draw after a brief flush) to
determine if potential contamination is localized or systemic. A stagnation period is a deviation from
the collection procedures in most standard VOC methods and should be noted to all involved. Samples
should be collected by individuals who have been properly trained on the sampling protocol, marked as
investigative samples, and analyzed by a certified laboratory that has been informed of the protocol. State
drinking water regulatory agencies can provide a list of certified drinking water laboratories. Utilities
should discuss with the laboratory whether rapid turn-around for the analytical results is available
during emergencies.
Sampling Locations in Distribution System: Deciding where to sample in the system can be difficult.
Potential areas for contamination are within or near the burned area served by the distribution system.
Research suggests a correlation between the density of burned structures and VOC contamination.6 One
utility found that over 50% of service connections at burned lots contained fire-related contamination. Areas
that lost pressure (e.g., pipe break, leaks, higher elevations) should also be prioritized for sampling since
contamination has been associated with a loss of pressure. Areas that were exposed to heat, especially if
they contain plastic materials, should be considered for sampling since VOCs can be released without direct
damage and failure of the system. However, all types of pipe materials (e.g., metal), not only plastic, should
be considered for sampling, as elevated VOC concentrations have been detected in water from metal piping
following wildfires.2 Drinking water utilities should use a systematic approach to assessing the system.
For example, initial sampling locations could include the entry point to the distribution system and service
mains to determine the location of any contamination across the distribution system. Sampling should
also occur at service connections that are preparing for re-occupation to determine if there is any potential
contamination for returning consumers. Service connections at burned structures should be sampled and
confirmed to be unimpacted before the connections are returned to service.
Sampling Locations at Surviving Buildings: In addition to the distribution system, sampling in surviving
buildings and homes should also be considered. Individual property owners are typically responsible for
their own plumbing (i.e., service connection from the meter to the building and indoor plumbing). Utilities
are usually not reguired to collect samples from inside structures; however, public health agencies, utilities,
and state drinking water regulatory agencies can provide property owners with a list of certified drinking
water laboratories and advice on sample collection and handling. There are currently no standards or
accepted protocols for sampling buildings or homes for VOCs. As a general guide, sample collection in
a building should focus on the points of greatest concern for the building occupant/owner. For example,
sampling from the kitchen sink will provide information about the water used for drinking and cooking.
Additionally, showers/bath spouts and bathroom faucets can be sampled given the potential for inhalation
or dermal contact. Certified laboratories often provide protocols for sample collection but concerned
property owners will likely need to collect the sample on their own.
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Data Quality and Management: For sampling the distribution system, there should be consistency in
sampling locations, sampling and analytical procedures, and laboratories used. Appropriate guality
assurance/guality control procedures should be included in the sampling and laboratory procedures to
ensure data collected and analyzed by multiple sources are comparable. To review the data, it can be useful
to develop a spreadsheet of sampling locations. Mapping the data can be especially useful because it can
highlight geographic patterns of VOC levels (and MCL exceedances). When sharing data with the public,
private contact information and potentially the results themselves may be considered sensitive information,
and therefore utilities may want to consult with the state regulatory agency before disclosure.
Addressing the VOC Issue
Addressing VOC contamination reguires immediate as well as long-term actions. Utilities should utilize their
risk and resilience assessments and emergency response plans as well as work with their state regulatory
agency to identify the most appropriate options for their situation.
Advice on Drinking Water Advisories: Following a loss of pressure, "Boil Water" advisories are commonly
issued to protect against microbial contamination; however, until VOC contamination is ruled out, boiling the
water or hot water use (e.g., showering) could create an inhalation risk. If there is suspected or confirmed
VOC contamination, the utility and the state regulatory agency should consider issuing public health
advisories such as "Do Not Drink", "Do Not Drink - Do Not Boil", or in extreme cases, "Do Not Use."
Alternative Water: Because addressing VOC contamination takes time, the immediate need of the
utility may be to provide alternative water (e.g., bottles) after wildfires, even for structures that appeared
unimpacted. This need could persist due to the initial effort to determine the existence and extent of
contamination and then due to any remediation efforts. State drinking water regulatory agencies have
Emergency Drinking Water Supply Plans to address drinking water needs during an incident/disaster.7
Utilities should work with their state regulatory agency to select and implement alternative water strategies,
such as points of distribution for bottled water, water storage tank installations at homes and businesses,
and water deliveries.
Flushing Protocols: Following both the Tubbs and Camp wildfires, flushing was used to decrease VOC
contamination. It is important to conduct unidirectional flushing as soon as possible to completely
replace the VOC contaminated water with fresh water. Flushing immediately minimizes permeation
of the VOCs into infrastructure. If permeation has occurred, multiple flush cycles may be necessary to
account for VOCs slowly re-entering the water. Flushing should begin at the water source and proceed
downstream throughout the distribution system. Samples collected after flushing typically contain lower
levels of contamination than initial samples. However, because flushing may not always reduce the VOCs
to the desired levels even after repeated applications, it should be coupled with sampling after a period
of stagnation to assess effectiveness. After utility water mains have been flushed, customers should be
instructed to flush their building plumbing in a manner similar to that of water systems, i.e., from a tap (sink,
spigot, etc.) closest to the service connection to the tap farthest from the service connection.
Isolation: Isolating, or valving off, areas of the system into zones can be an effective way to prevent
contaminated water from flowing into unimpacted areas as well as progressively returning the system
to operation. When coupled with flushing and sampling, areas can be cleared of VOC contamination and
returned to service in stages while other areas are still being addressed. Isolation should be evaluated
carefully due to the potential for negative impacts, such as loss of pressure in portions of the system.
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Confirmation that Service Connections are Clear: Undamaged structures are less likely to have a VOC
contaminated service connection; however, they can become contaminated when the system repressurizes
and, therefore, should be sampled prior to restarting service. Based on experiences during the Camp
Fire, utilities should be able to confirm that the connection is ready for service after tests reveal that
VOC concentrations are at levels deemed safe for use. Connections that have contamination should be
addressed with other measures as described in this section. Utilities should use care when asserting which
parts of the system (e.g., from a service line to a group of homes) are cleared of VOCs, because a system
without backflow prevention can potentially spread contamination from service connections to water
mains. Water mains should be fully pressurized and confirmed to be clear of VOCs before attempting to
confirm service connections are clear.
Treatment Devices: Pitcher filters, point-of-use devices (e.g., under-counter filters), and/or whole building
treatment devices can be effective at treating VOC contamination when designed and maintained properly;
however, these devices have limitations. Where VOC concentrations exceed the treatment abilities of these
devices, VOCs will pass through the devices untreated. Drinking water utilities that elect to utilize localized
treatment devices should do so in consultation with their state regulatory agency. Utilities should advise
individual customers who are considering installing such devices independent of a recommendation from
the utility or state regulatory agency to adopt a cautious approach. Safe use of these devices requires
knowledge of the contaminants present and their concentrations in the drinking water, other water quality
characteristics, the manufacturer-specified and independently certified treatment capabilities, and the
design life of the treatment device.
Replacement: For pipes and other system
infrastructure that are damaged or cannot be flushed
effectively replacement should be considered. The
cost of water pipe repair and replacement varies
widely depending on the extent of the damage.
Utilities should consider prioritizing the replacement
of water lines in locations that coincide with
rebuilding (e.g., after building permits are issued).
Also, physical examination (e.g., camera inspection,
destructive sampling) of the pipes may be useful to
prioritize replacement. It is important to document
VOC contamination and the physical characteristics
of damage to qualify for federal disaster assistance
to replace infrastructure.
Mitigation, Measures to prevent VOC contamination
in water utility infrastructure after wildfires
have not yet been proven. Flowever, reasonable
countermeasures against VOC contamination
could include backflow prevention on all service
connections, fireproof concrete meter boxes, and
brass meters.8
Long-term Monitoring: After VOC contamination has
been addressed, utilities should consider if a long-
term monitoring program for VOCs is appropriate.
Such a program can confirm that contamination no longer remains in the system over an extended period
and serve to boost consumer confidence. While no standard exists for a monitoring program, it should
include the same considerations described in the "Testing for Contamination" section.
Service Line Replacement
Credit: Paradise Irrigation District
Concrete Meter Boxes
Credit: Paradise Irrigation District
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Mutual Aid and Funding for VOC Sampling, Analysis, and Remedies
Following a wildfire, a utility can face many challenges returning the system to operation including, but
not limited to: damage to facilities and service connections, lack of needed eguipment or materials, and
limited personnel who are themselves facing wildfire impacts to their homes and community. The Water
and Wastewater Agency Response Network (WARN) and other mutual aid and assistance programs exist to
provide utilities with the resources they need during an emergency. Through mutual aid agreements, utilities
can provide eguipment, generators, supplies, or personnel to support recovery activities at impacted utilities.
Utilities can work with nearby utilities to foster mutual aid agreements and engage with larger programs, like
WARN, to ensure they have a support system in place. If there is justification for emergency drinking water,
the utility can coordinate with their local emergency management agency.
After a wildfire, costs of utility infrastructure damage and lost revenue, as well as the costs to identify
and address VOCs in drinking water distribution systems, may be of concern. Public funding may be
available for utilities to address VOC contamination. If the wildfire has received a Presidential Disaster
Declaration, funding may be available from FEMA for public and private non-profit utilities under the Public
Assistance Program. Possible eligible expenses include costs for increased analytical testing to determine
contamination immediately after the incident, costs for obtaining water from an alternate source, and
costs for damage to infrastructure and VOCs in the distribution system. Utilities may also receive financial
assistance for measures to protect public health and for permanent repairs. Mitigation grants to retrofit
water systems (e.g., replace water systems that have been burned and are contaminated) may be available
through FEMA's Fire Mitigation Assistance Grants and FEMA's Hazard Mitigation Grant Program.9 EPA
Drinking Water State Revolving Funds (DWSRF) can be used in limited cases for sampling and analysis
as part of rebuilding utility assets with additional resilience measures to better withstand future disasters.
Also, the revolved portion of the DWSRF can be used as the state and local match for FEMA funds (see
Memorandum of Understanding). For small utilities serving populations less than 10,000 people, the U.S.
Department of Agriculture has grants and loans to address water guality issues, which could include VOCs
in water supplies after wildfires. Technical assistance for infrastructure recovery may also be available if the
state reguests federal help under the Federal Disaster Recovery Framework.
For many of these programs, documentation of the infrastructure damage and the steps taken to recover
from the wildfire are critical for securing financial assistance. It is recommended that all actions be
documented, even before applying for financial assistance. For home and building owners, financial support
may come from FEMA's Individual Assistance Program or homeowner/building insurance.
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1	Drinking water contamination from the thermal degradation of plastics: implications for wildfire and
structure fire response, Kristofer P. Isaacson, Caitlin R. Proctor, Q. Erica Wang, Ethan Y. Edwards, Yoorae Noh,
Amisha D. Shah, and Andrew J. Whelton, Environmental Science: Water Research and Technology, 2021, 7, 274-
284, https://doi.Org/10.1039/d0ew00836b
2	Wildfire caused widespread drinking water distribution network contamination, Caitlin R. Proctor; Juneseok
Lee; David Yu; Amisha D. Shah; Andrew J. Whelton, AWWA Water Science July/August 2020 el 18324, Volume2,
Issue4; https://d0i.0rg/l 0.1002/aws2.1183
3	Impact of petroleum-based hydrocarbons on PE/PVC pipes and pipe gaskets, Say Kee Ong, James A. Gaunt,
Feng Mao, Chu-Lin Cheng, Lida Esteve-Agelet, and Charles R. Hurburgh, AwwaRF, Denver, CO., 2007; https://www.
waterrf.org/research/projects/impact-hydrocarbons-pepvc-pipes-and-pipe-gaskets
4	Do-Not-Drink and Do-Not-Boil Water Advisory Issued for Two Specific Areas of Fountaingrove. Retrieved
6/1/2021 from https://www.sonomacountyrecovers.org/not-drink-not-boil-water-advisory-issued-two-specific-
areas-fountaingrove/
5	Paradise Irrigation District (PID) advises bottled water only for drinking, cooking and brushing teeth.
Retrieved 6/1/2021 from https://pidwater.eom/wqadvisory/40-wq/101 -paradise-irrigation-district-pid-advises-
bottled-water-onlv-for-drinking-cooking-and-brushing-teeth
6	Prediction of Water Distribution System Contamination Based on Wildfire Burn Severity in Wildland Urban
Interface Communities, Stefanie S. Schulze and Erica C. Fischer, ACS ES&T Water https://d0i.0rg/l 0.1021 /
acsestwater.0c00073
7	Planning for an Emergency Drinking Water Supply, US Environmental Protection Agency, EPA 600/R-11/054;
June 2011: https://www.epa.gov/sites/production/files/2015-03/documents/planning for an emergency
drinking water supplv.pdf
8	Backflow Prevention required for all water connections in Paradise Irrigation District. Retrieved 6/1/2021 from
https://pidwater.com/backflow
9	Job Aid for Disaster Recovery Reform Act, Section 1205, FEMA; December 2019, https://www.fema.gov/sites/
default/files/2020-07/fema DRRA-1205-implementation-job-aid.pdf
Office of Water (4608-T) EPA 817-F-21 -011 October 2021
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