Airline Water Study 2019 FAQs

by Charles Platkin, PhD


General FAQ 

  1. What is the ADWR? 

The ADWR is a set of regulations meant to ensure the safety of drinking water on aircraft. 

  1. What prompted the EPA to create the ADWR? 

In 2004, the EPA found all aircraft PWSs to be out of compliance with the National Primary Drinking Water Regulations. This prompted the agency to create a new set of drinking water regulations specific to aircraft. 

  1. What kind of aircraft are required to comply with the ADWR? 

The ADWR is a subpart of the National Primary Drinking Water Regulations. Aircraft with water systems on board that meet the criteria of “public water systems” as defined with the SDWA and NPDWRs, and that board only finished water for human consumption must comply with ADWR regulations. Aircraft are considered “transient non-community water systems.”

  1. When did the ADWR go into effect? 

Applicable aircraft needed to comply with ADWR regulations beginning October 19, 2011. 

  1. Which agencies enforce the ADWR? 

Drinking water safety on air carriers is jointly regulated by the EPA, FAA, and FDA. However, the EPA is the agency that enforces the statutes of the ADWR. 

  1. How are international air carriers regulated? 

International aircraft that only make one stop in the U.S. for the sole purpose of unloading passengers transported from outside the US and/or loading passengers for transportation to a destination outside of the U.S. are generally excluded from ADWR regulations. In other words, if an aircraft services two or more U.S. locations before returning to an international location, that aircraft must comply with the ADWR while it operates within the U.S.

U.S. air carriers must include their procedures for boarding water into their O&M plans to be approved by the FAA. Part of those procedures includes: “A description of how the carrier will ensure that water boarded outside the United States is safe for human consumption.”

  1. What does the ADWR say about chemical, rather than bacterial, contamination?

As of now, the ADWR only outlines procedures for addressing bacterial contaminations.

  1. What if air carriers want to do more than the minimum recommendations of the EPA? 

The ADWR does not outline any suggested procedures beyond their minimum requirements. However, the rule states that air carriers may introduce supplemental treatments into their routine plans, so long as the treatments are approved by the FAA and FDA. The supplemental treatments may not act as a replacement for the ADWR. 

  1. Has the ADWR been updated since 2011? 

In 2016, the EPA implemented the “Revised Total Coliform Rule (RTCR)”, which made revisions in maximum contaminant levels and treatment technique requirements. However, this revised rule applied to all public water systems, not just aircraft. All public water systems under the ADWR were required to analyze their water samples for coliform and E. Coli following the provisions of the RTCR beginning April 1, 2016.

  1. What if the water from the local municipality is found to have contaminants that may be hazardous to human health?

The ADWR does not go into great detail about the water quality of municipalities surrounding airports. However, it does state that if the public water system that provides water to be boarded onto the aircraft is out of compliance with NPDWRs, it is required under the NPDWRs to notify all users of that water system, which naturally includes airport authorities. 

Coliform and Sampling FAQ 

  1. Where are the water samples tested? Who are they tested by? 

Water samples are collected by the air carriers themselves. The physical water samples are then sent to and tested by EPA-approved laboratories. 

  1. Do aircraft close to the public if a water sample is found the be contaminated with E. Coli?

The aircraft must restrict access to water on board within 24 hours if a water sample is determined to be contaminated with E. Coli. Disinfection and flushing procedures must take place within 72 hours of the discovery. A follow-up sample must be collected, and the results must be coliform-negative before the aircraft provides water for human consumption. However, passengers and crew can still remain on the aircraft as long as public access to the aircraft water system is barred. 

  1. What if a water sample is found to test positive for coliform, but negative for E. Coli? 

A positive test for coliform may indicate that dangerous pathogens may be in the water tank. If any routine, repeat, or follow-up coliform sample is coliform-positive, the air carrier must also test to determine if E. coli is present in the sample as well. The aircraft cannot provide water for human consumption until the follow-up samples are coliform negative.

 In this scenario, the aircraft must perform at least one of the three following options, and continue with that option, until a follow-up sample is coliform-negative:

  • Disinfect and flush the water system within 72 hours of the discovery 
  • Restrict public access to the water system within 72 hours of the discovery and conduct disinfection and flushing procedures
  • Conduct repeat samples: collect three 100mL samples within 24 hours of the discovery (one sample from the lavatory, one sample from the galley, and one sample from the tap that yielded a coliform-positive result)
    • If all samples are found to be coliform-negative, then the aircraft may proceed its routine coliform sampling procedures as outlined in their FAA-approved O&M plans.
    • If samples are still found to be coliform-positive, aircraft may follow the procedures of one or both of the first two bullet points above (disinfection and flushing, and restricting public access)
    • If samples are found to be E. Coli-positive, then they must proceed with the instructions listed in question 2. 
  1. What if an aircraft simply doesn’t conduct the minimum number of water tests, as recommended by the EPA? What if an aircraft doesn’t conduct the minimum amount of D&F as outlined in their O&M plan? 

 If an aircraft does not analyze routine water samples and comply with a routine D&F schedule, then corrective action must be taken. The aircraft must restrict public access to the water system within 72 hours. The aircraft must then disinfect, flush, then send the water samples to an EPA-approved lab for analysis. Public access must remain restricted until the analyses yield coliform-positive results. The EPA requires that air carriers report this failure to complete routine testing within 10 days of the discovery of the error, even if the water sample is found to be safe for human consumption. 

A similar procedure must be taken if an aircraft fails to collect repeat or follow-up samples of a coliform-positive result

A similar procedure is also followed if an aircraft fails to collect repeat or follow up samples of an E. Coli positive result. The only difference in this case is that public access must be restricted within 24 hours. It also must conduct D&F procedures within 72 hours. 

What if an aircraft pumps water into its tank from a water source that is not approved by the FDA, and later discovers the water is contaminated?

If the results of the water sampling analysis reveal that the water is coliform-positive, then the aircraft must restrict public access to the water system within 72 hours, perform D&F, and continue water analysis until results are coliform-negative.

If the results of the water sampling analysis reveal that the water is E. Coli-positive, then the aircraft must restrict public access within 24 hours and perform D&F procedures no later than 72 hours after the discovery. The follow-up water sample must be coliform-negative until public access is granted again. 

  1. Is coliform dangerous?

In and of itself, not necessarily. Coliform bacteria are commonly found in the environment and in the feces of warm-blooded animals and are not likely to cause illness. 

There are a number of pathogens that arise as a result of fecal contamination, but their concentration within the water is often small. Therefore, specific testing for individual illness-inducing pathogens that result from fecal contamination can be expensive and time-consuming. 

Coliform, on the other hand, arise from the same sources as pathogens but are often present in a larger concentration than individual pathogens. This makes them easier to detect. Coliform also respond to water treatment and sampling similarly to many pathogens.

Therefore, the presence of coliform may indicate that there are disease-causing bacteria within a water sample.

Public Notice And Public Access FAQ 

  1. How does the air carrier restrict public access to the water system?

Air carriers may follow one or more of the following procedures to restrict public access to the water system:

  • Physically disconnect or shut off the aircraft water system, where possible, or otherwise prevent the flow of water through taps
  • Provide public notification to passengers and crew 
  • Provide alternatives to water from the aircraft water system (such as bottled water for drinking and coffee or tea preparation, antiseptic hand gels or wipes for sanitation)
  1. How do passengers have access to water on flights if water samples are found to be unsafe for human consumption?

In this case, the EPA recommends that air carriers provide passengers with alternatives such as bottled water, antiseptic hand sanitizers, and sanitary wipes. 

  1. Does the EPA need to know that an air carrier made a public notice or restricted access to the aircraft water system? 

Yes. Air carriers must report these situations within 10 days of the event. 

Reporting FAQ 

  1. Do EPA agents inspect water samples from aircraft themselves?

No. Air carriers hear back from the laboratories, and air carriers must keep records of all testing results (see question 5 of this section).

  1. How do air carriers report information to the EPA? 

Air carriers primarily report information to the EPA with the use of The Aircraft Reporting and Compliance System, or ARCS, an online database administered by the US EPA Office of Water, Office of Ground Water and Drinking Water, Drinking Water Protection Division. The logic behind self-reporting with an online database is that this method of reporting reduces human error. The database is accessible to four types of users: primary airline representatives, secondary airline representatives, laboratory staff submitting data on behalf of airlines, and EPA staff.

To be in compliance with the ADWR, air carriers must report the following information to the database:

  • All existing aircraft inventory, including any changes to aircraft inventory
  • All instances of routine disinfection and flushing
  • All coliform sampling results, including any sample result that yields an E. Coli positive or coliform positive result
  • Any event that calls for the introduction or cessation of public notice (and subsequent return to routine sampling and monitoring)
  • Any event that calls for the restriction or re-introduction of public access (and subsequent return to routine sampling and monitoring)
  • Any failures to conduct routine D&F or water sample analysis
  • Self-inspection confirmation 
  • Any changes in the frequency of D&F procedures or water sample analysis. The O&M plan must subsequently be updated. 

Air carriers typically must electronically report this data within 10 days. They can, however, report their self-inspection results (including any deficiencies found) within 90 days. Air carriers must also report any corrective action they haven taken in regard to the above scenarios.

  1. Do air carriers have to report anything to the FAA and FDA as well?

Aircraft must create an operation and maintenance plan for the operation and maintenance of potable water systems on aircraft. These plans must be approved by the FAA

The FDA must also approve of the water points from which aircraft load water on board, and can conduct airport inspections to ensure that airports are in compliance. (See here, here)

  1. How does the EPA ensure that air carriers complete the mandatory self-inspection every five years?

Air carriers must report that they completed the self-inspection in the ARCs database within 90 days of the inspection. Any deficiencies found during the self-inspection must also be reported and addressed within 90 days of the inspection. If the deficiency is still not addressed within 90 days and the aircraft is still being used for passenger service, then air carriers are in violation of the ADWR. See Violations FAQ for more details. 

  1. Do air carriers have any obligations to keep records of routine activities? 

Yes. Air carriers must keep a copy (either electronic or hard copy) of:

  • Self-inspection reports (for 10 years)
  • Bacteriological Analyses and D&F data (for 5 years)
  • Public Notification (for 3 years)
  • Air carriers must have current copies of their O&M and sampling plans on hand

Violations FAQ

What exactly would constitute a violation of the ADWR? 

The EPA would consider the following actions to be in violation of the ADWR:

  • Failing to conduct routine, repeat, or follow-up coliform testing and disinfecting and flushing procedures as outlined by the ADWR
  • Having an E. coli‐positive sample during any monitoring period 
  • Failing to provide public notification to passengers and/or crew when applicable
  • Failing to meet reporting and recordkeeping requirements
  • Failing to correct a deficiency (i.e., an E. Coli-positive sample)
  • Failing to conduct a complete self-inspection of the entire aircraft water system every five years, and failing to correct any deficiencies found during self-inspection
  • Failing to develop an FAA-approved O&M plan or an EPA-approved water sampling plan

Are records of these violations available to the public?

Yes. The EPA maintains an ADWR Compliance Report database, an online record of self-reported data on aircraft inventory, water systems operation plans, disinfection and flushing plans, water sampling results, public notice information, and violations. 

The rule requires air carriers to report failures and corrective actions they take to address the failure, when applicable. But what about the EPA? But besides maintaining the ADWR Compliance Report database and taking note of violations, how else does the EPA respond to violations? 

Both the ADWR Violations training guide and the ADWR itself does not go into detail about the actions the EPA may take when faced with the above failures. 

Does the EPA perform any routine audits or inspections of aircraft?

Yes. The rule grants the EPA power to conduct compliance audits as deemed necessary (in other words, they are not “routine.”) If a deficiency is found during a compliance audit, aircraft have a maximum of 90 days to correct the deficiency (this same procedure is also followed if a deficiency is found during a self-inspection). If an aircraft does not correct the deficiency within this time frame, an air carrier representative must provide a written explanation as to why the deficiency has not been addressed. The explanation must include a schedule for addressing the deficiency as quickly as possible. 

Are there monetary fines associated with air carriers violating the ADWR? 

Yes, the EPA can and does levy monetary fines on air carriers for failing to comply. See examples here and here

Questions Posed to the EPA Office of Public Affairs and Its Responses

Question: Our research team found that the “ADWR Compliance Public Reports” page lists seven types of violations: Administrative, Monitoring, Maximum Contamination Level, Public Access, Reporting, Treatment Technique, and Other. Can you please provide links to what constitutes a violation in each of these categories? We attempted to locate and could not find. Alternatively, if this information is not available online, can you please provide details on what constitutes a violation for each.

Response: Violations possible under the ADWR are described in 40 CFR Part 141.810: Violations, and are provided in EPA’s training presentation: Part 6 here:

Question: What happens if an airline fails to comply with the corrective action requirements of a violation? See: 40CFR 141.810(a). What are the steps the EPA follows to secure compliance?  

Response: It is the airline’s responsibility to return to compliance.  40 CFR Part 141.803 and 141.804 discuss corrective actions and 141.810 describes the possible violation under the ADWR.

Question: The Administrator of the EPA can request airlines to post a public notification when it “determines that notification is necessary to protect public health.” How does the EPA enforce this mandate and ensure that airlines make public notifications?

Response: The requirements to post notifications are described in 40 CFR Part 141.805: Notification to passengers and crew,  and the violation for failure to provide notice to passengers and crew is described in  40 CFR 141.141.810(c): Violations.

Question: Airlines can and often do receive multiple violations. Are there consequences associated with multiple violations by a specific airline within a given timeframe? If so, what are the consequences and what is the given timeframe (i.e., one year, five years, …)? 

Response.  Where the airline is issued multiple violations they would be responsible for addressing each violation, whether the violations occur in a single compliance period or over multiple compliance periods.

Question: The ADWR Compliance Public Reports Violations Report page suggests that violations should be issued any time an aircraft’s water sample tests positive for E. coli. (“Violations involve … [cases] where any sample result is E. coli positive”). Our research team found a discrepancy between the number of “Maximum Contaminant Level” violations (131 as of 8/4/19) issued for all airlines, and the number of E.coli-positive results indicated by the “Aircraft Drinking Water System Operations” and “Aircraft Sampling Operations” (both show 176 as of 8/4/19) pages. Can you explain this discrepancy?

Response: It’s possible for a single aircraft to have more than one E. coli positive result (e.g. positive results in the lavatory and galley). MCL violations are assigned to the aircraft.

Question: Does the EPA have the authority to shut down an aircraft due to a public health risk associated with onboard water of an aircraft? If so, what specific types of onboard water related violations/public health risks would generate a closure? If not, is there another agency that retains this authority? Have there been any instances where a plane was grounded because of an ADWR violation?

Response: The ADWR includes requirements for Aircraft water system operations and maintenance plan (40 CFR Part 141.804) and Notification to passengers and crew 40 CFR Part 141.805 in the event there is a risk to public health associated with onboard drinking water. Recommend reaching out to FAA regarding requirements to shut down and aircraft.

Question: Are there any circumstances in which EPA agents must board an aircraft to inspect the water quality, deal with repeat violations, and/or any other water related issue? If so, what are those circumstances?

Response: The EPA may conduct routine compliance audits as deemed necessary in providing regulatory oversight to ensure proper implementation of the requirements of the ADWR, see 40 CFR Part 141.808.

Question: How does the EPA ensure that self-reported information (bacteriological analyses, aircraft water system disinfection and flushing events, any self-inspection reports, coliform sampling plans, water system operation and maintenance plans, copies of public notice to passengers and crew) submitted to the Aircraft Reporting and Compliance System (ARCS) and EPA is accurate? Are there any sworn statements, affidavits or penalties of perjury for the signator or person filing the report? Can you please provide an example of a form that requires self-reported data?

Response: Air carriers are required to submit information electronically to the Airline Reporting and Compliance System (ARCS). The ARCS database includes an electronic signature component that air carriers must sign upon each entry to verify the submitted information is accurate.  ARCS was designed to meet the requirements of the EPA Cross-Media Electronic Reporting Rule (CROMERR) which provides the legal framework for electronic reporting under EPA’s regulatory programs.

The EPA further ensures that the ADWR self-reported information is accurate by performing onsite compliance audits of the aircraft and aircraft records. The EPA may review records, collect coliform samples, and observe procedures at any time. Air carriers must keep records to document activities performed for compliance with the ADWR. The ADWR recordkeeping requirements can be found in 40 CFR 141.807.

Question: Notice to the public is required under certain circumstances including the following: any sample results that are total coliform-positive or E. coli-positive; an air carrier fails to perform required routine disinfection and flushing; an air carrier fails to collect required samples; an air carrier boards water from a watering point that does not meet FDA regulations, EPA standards, or is otherwise determined to be unsafe; the EPA, the air carrier, or crew determines public notification is necessary to protect public health. That notice can occur through the following options:

  •     Broadcast over a public announcement (PA) system on aircraft
  •     Posting of the notice in conspicuous locations (such as all the galleys and lavatories in the affected aircraft)
  •     Hand delivery of the notice to passengers and crew
  •     Another delivery method approved in writing by EPA.

How does the EPA ensure that notice is made to the public through one of these methods? Besides the airline self-reporting that a notice has been made, are there ever physical random checks by the EPA to ensure notice has been made? Is there visual evidence required to support self-reported data? When airlines self-report data are they required to sign an affidavit or sworn statement? Is there a penalty or it is a crime to submit false information? If so, can you please send us a copy of such?

Response: The EPA may review records, collect coliform samples, and observe procedures at any time. Air carriers must keep records to document activities performed for compliance with the ADWR. The ADWR recordkeeping requirements can be found in 40 CFR 141.807. As noted previously, the Agency has the authority to conduct routine compliance audits as deemed necessary in providing regulatory oversight to ensure proper implementation of the requirements of the ADWR, see 40 CFR Part 141.808. Failure to perform any ADWR requirement is a violation. Not taking corrective action to return to compliance may lead to enforcement actions. To date, air carriers have corrected violations within the timeframes stipulated by EPA.

Question: Only bacterial contaminants are addressed by the ADWR. Are any procedures in place to prevent other forms of water contamination aboard aircraft, such as chemical contamination? If so, which agency or agencies are responsible for these regulations?

Response: Water that is used for aircrafts is provided by public water systems.  These PWS are required to test for and monitor a variety of contaminants that are subject to EPA’s National Primary Drinking Water Regulations (NPDWR). EPA’s ADWR rule was designed address unique characteristics of aircraft public water systems for the enhanced protection of public health against illnesses attributable to microbiological contamination.

Because aircraft water comes from locations via temporary connections, aircraft drinking water quality depends on a number of factors (e.g., the care used to board the water, the water transfer equipment (such as water cabinets, trucks, carts, and hoses), and the operation and maintenance (O&M) of the onboard water system). The ADWR applies to the onboard water system only.

The ADWR, along with complementary US Food and Drug Administration (FDA) regulations, addresses each of these factors in order to safeguard against possible contamination and to ensure that the water is suitable for human consumption.  

Question: The EPA website states that: (1) the EPA regulates systems that supply water to airports and on board aircraft; (2) the FDA regulates water used in food and drink preparation and water supply lines for the aircraft; (3) the FAA oversees airline operation and maintenance programs, including the potable water system.” Are we correct in our interpretation that it is the responsibility of the EPA to regulate the safety of water tanks on aircraft, in addition to the vehicles that transport water to the aircraft (e.g., Water trucks, hoses)? If our interpretation is incorrect, please clarify how the EPA’s role differs from that of the FAA and FDA.

Response: The EPA does not have jurisdiction over aircraft equipment or vehicles that board water. Section  141.801 defines applicability and section 141.804(b)(1) clarifies EPA responsibilities compared to FDA (i.e.,  FDA 21 CFR part 1240 subpart E).

Question: How often are the vehicles that transport water in and out of the aircraft water tanks (e.g.,. tanks, hoses, connecting valves) subject to cleaning and inspection to avoid bacterial contamination? 

Response: The EPA does not have jurisdiction over the vehicles that board water. Applicability under the ADWR is described under 40 CFR Part 141.800: Applicability and compliance date and does not include the delivery of the water to the aircraft. Section 141.804(b)(1) specifies that watering point selection requirements must be selected in accordance with Food and Drug Administration regulations 21 CFR part 1240 subpart E.

Question: The ADWR manual does not explicitly state the exact/recommended products that airlines should use to disinfect and flush water tanks on board. Are there products that are standardized across the industry, or is the choice of product entirely left to the discretion of the airline? 

Response: The EPA does not specify what products are used; rather, the EPA specifies that operation and maintenance follow manufacture recommendations.        

Question: In a memo titled “Aircraft Drinking Water Rule: Moving aircraft into a ‘Pending Bin’ in the Aircraft Reporting and Compliance System due to bankruptcy or other changes in operations“ it refers to the “Office of Enforcement and Compliance Assurance’s (OECA) Water Enforcement Division’s June 15, 2011 ADWR National Compliance and Enforcement Strategy” (June 2011 ADWR Strategy) and “OECA/OGWDW’ s joint February 29, 2012” memo. However, our research team was unable to find these two memos online. Can you please send us the links to these memos and or copies?

Response: Note both documents described above can be found online under:

ADWR Memos:;


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