Aqua Answers - How do I keep everything straight?

Dear Aqua Answers,

As an operator, there’s a lot going on. How do I keep everything straight?

Thanks,

Stacie Indeno

Dear Stacie,

Public water systems need to meet many drinking water regulatory requirements to protect public health. This includes monitoring and reporting. Keeping track of all this information may be overwhelming for operators, owners, and administrators. As a result, we have developed several assistive tools that can help avoid an unnecessary violation. These include the following: 

Monitoring Schedules: 

Your online monitoring schedule is the first and best place to start. This document identifies your system’s testing requirements and deadlines. 

• You can find your system’s online monitoring schedule at the division's drinking water schedule website. You can then search by your system’s PWSID (COXXXXXXX) or “System Name”.
• Your monitoring schedule details your system’s information, including your Facility ID, Sample Point ID, and the monitoring collection period. 
• You should always have an up-to-date copy at all times. This could be an electronic copy or a paper copy kept in your compliance binder. 
• You should always use your monitoring schedule to fill out your chain-of-custody (COD) form. 
• Monitoring requirements are marked as “Sample Result(s) Received” and struck out on your monitoring schedule once they are submitted and processed (excluding total coliform sampling - please see the AIMs tool listed below). Please be aware that it may take us several days to process the data. If data is submitted incorrectly, we will not process the data. The requirement will then remain on the schedule. If there is an error, please contact your assigned drinking water compliance specialist.
• We update the monitoring schedules every Thursday. 

Am I Missing Something? (AIMS) Tool: 

You can use our brand new AIMs Tool to check total coliform sample and chlorine residual submissions. 

• The AIMS tool can identify missing samples or data errors for total coliform samples. If there is an issue with the sample result, the tool highlights the sample in red. The most common issues we see are that 1) the sample is missing or 2) the chlorine residual was not reported. 
• If you are a listed contact for many water systems (e.g., you are a contract operator), you can sort the tool by your name. This allows you to check all your water systems at a glance. 
• We have developed a User Guide: Am I Missing Something? (AIMS) Tool for tips and tricks on using this new tool. 

Reporting Guidance: 

• We always encourage systems to collect their required samples early in the collection period. Our motto is “Sample early and sample often!” 
• Fill out your COD form correctly. By law, we must process the data exactly as provided. If the result has missing or incorrect information, it will not be processed. This will result in a reporting violation. 
• All sample results must include the following information provided by the PWS: 
• PWS ID;
• Facility ID;
• Sample Point ID; and
• Collection Date.
• Except for hand pumps and disinfection waivered systems, all total coliform sample results must also include the measured chlorine residual and labeled as free or total. 
• Please do not add any extra information into the Facility ID or Sample Point ID sections. Adding additional information to these fields will result in a violation since we cannot process the sample result. If you must include more information, use the comment or address field. 
• It is always the water system’s ultimate responsibility to report by the deadline. Even if the lab is in error, we still have to issue the violation to the water system. 
• While not required, most labs submit the drinking water results on behalf of their customers. This is the easiest and preferred method for submitting sample results. 
• We highly encourage you to work with your lab and ensure that they are meeting the reporting deadlines. 
• If your lab is reporting your data, they must report the results to us as a CSV file. A CSV file helps report the data in a tabular format. You can still access these results under “My…Sample Results” in the drinking water portal.
• We have developed more guidance for properly reporting sample results, including: 
• Tips on accurately submitting sample result
• WQCD Guidance and Resources for Laboratories
• Timely reporting guidance document
• If you are submitting a COD for public notice requirements (e.g., Consumer Confidence Reports, public notice for violations, lead consumer notification, etc.): 
• Ensure a representative copy of the notice is included in your submittal. 
• Please be aware that you cannot certify that an activity was completed in the future. Only submit the COD and the representative notice copy after the required action is completed.

Mistakes and Errors: 

1. If you have made a reporting mistake, there are three main ways that you can address the error:
2. Work with your lab to have the data corrected and resubmitted. This is the preferred method and often the easiest for water systems. 
3. Submit a Sample Correction Form with all the correct information. This will help us identify and address the issue. 
4. Submit a copy of sample results with corrected information clearly provided. This is the least preferred option as we cannot readily determine what the issue is with the data.  

**Any corrections must be received by the applicable reporting deadline. If they are received after the deadline, your system will receive a reporting violation.** 

Sampling Reminders:

Sample results must be submitted no later than the first 10 calendar days following the end of the monitoring period. Generally, this is no later than the 10th of the month after the end of the monitoring period. 

• For example, you must collect a disinfection byproduct (DBP) sample every year. Thus, the monitoring period ends December 31st. Your results are due by January 10th.
• As an assistive effort, the department is sending reminder emails regarding potentially missing data around the 7th of every month. The best way to use these reminders is to submit your data early. That allows us sufficient time to process the data. If you received a reminder and your data was submitted early enough, there may be an error. Use the steps above to correct the issue.
• While not required, compliance specialists often send out additional reminders for other requirements. If you are receiving this help, take action! There may be something missing or incorrect.

Finally, if you are not receiving reminders, please make sure your contact information is correct. Your monitoring schedule lists your system’s Administrative Contact, Treatment Operator, Distribution Operator, and Owner. Remember, water systems are responsible to submit a contact update any time there is a contact change. This can be completed by either using the 1) monitoring plan wizard and checking the “01 Contacts” in the template or 2) using the contact update paper form. As always, if you have any questions or need additional assistance, please contact your assigned drinking water compliance specialist. 

Sincerely,

Aqua Answers

Cause for Concern: A Trend in the Submission of False or Misleading Application Information

So, What’s the Issue?

The Colorado operator certification program is seeing an increase in the submission of false or misleading certification application information by those applying to take exams. Colorado Certified Water Professionals (CCWP) office staff are seeing: 

• Expired identification information; 
• Forged education documentation; and/or
• False work experience information, such as:
• Inaccurate start/end dates. 
• False employers. 
• False self-employment information. 
• Misclassification of job roles (such as incorrect percentages applied or claiming small water or wastewater system experience when one’s work history is not reflective of that). 
• Misrepresentation of duties performed.
• Providing false, outdated, or incomplete supervisor contact information. 

Keep in mind that…

Submitting false or misleading application information on any relevant document provided to the Colorado Department of Public Health and Environment (Department), the Water Quality Control Division (Division), the Water or Wastewater Facility Operators Certification Board (Board), or its contractor (CCWP) is grounds for disciplinary action. 

Every time you submit an application through the CCWP Portal, you must affirm your agreement with the Colorado Certified Water Professionals Code of Conduct and with the Terms and Conditions, which includes your agreement to a thorough review of your application material. CCWP staff thoroughly review each and every application submitted by an operator to sit for an exam or to renew a certificate, and are obligated to submit a formal complaint of operator misconduct to the division upon identifying the submission of such false or misleading information. 

Disciplinary action can have serious consequences for an operator, not only negatively affecting their standing in the workplace and the community, but potentially their livelihood as well.

How to Avoid Submitting False or Misleading Application Information?

CCWP staff are extremely knowledgeable and more than happy to assist you in understanding the portal application process or to answer any questions you may have, including whether or not the information on an application is being accurately represented. If you’re not sure whether you’re accurately representing information on your application, don’t hit submit just yet. Contact CCWP for assistance. 

You can reach CCWP staff at (719) 225-7339 or info@coloradocwp.com. 

Set a Good Example and Uphold the Operator Profession

To become certified you had to meet specific regulatory requirements, demonstrate your special knowledge by passing an examination, agree to the Colorado Certified Water Professionals Code of Conduct, which insists that you protect the environment and the public health of the people you serve, and to maintain your certification by obtaining continuing education credit in the form of training units. If you hold an operator certificate, you are a professional and the Board holds operators to a high standard of professionalism. It also views as unacceptable any misconduct that undermines the integrity of the certified operator profession or puts the public health or the environment at risk. 

Be a good example for your fellow colleagues. If you see someone walking that fine line, stand up and say something; don’t turn a blind eye. The Board, CCWP, and the Division are your allies and we’re here to help you be successful, and we all want to uphold the operator profession. 

➽ Jessica Morgan, Facility and Operator Outreach and Certification Board Liaison

Culture of Health: Water Borne Disease Outbreak Rainbow Valley Ranch

The department promotes a ‘Culture of Health’ in order to encourage water providers to provide the highest water quality practical and to avoid waterborne disease outbreaks. Generally the department relies on what we call “performance partners” which are operators and suppliers of water to ensure the drinking water is safe. There are times that property owners do not cooperate and it becomes all the more important for the partnership between professionally certified operators and the department to stand firm. In the situation below, which did result in human illness, the contract operator that visited the site was instrumental in helping us understand and discern the facts on the ground. While ultimately the owner chose to sell off a portion of the property to avoid being a regulated public water system, the important realtime information from performance partners in the field helped mitigate the effects of this outbreak. As it stands today, the community should be receiving hauled water from a nearby regulated public water system that is safe to drink, however there is not regulatory oversight of the situation. 

The department values the public health professionals and certified water operators that are the ‘boots on the ground’ helping to protect public health and the environment every day. “If you see something, say something.” It may make all the difference in helping prevent or stop a waterborne disease outbreak.

Outbreak Summary Report:

Rainbow Valley Ranch is a small community and fishing club located in Teller County, Colorado. Before this outbreak, Rainbow Valley Ranch was considered to be a nonpublic water system as they served fewer than 25 people for at least 60 days of the year. Nonpublic water systems are not required to comply with the Safe Drinking Water Act and CDPHE has no regulatory authority over their water system.

According to residents of Rainbow Valley Ranch, people reported illness in April 2022, and CDPHE epidemiologists and WQCD staff worked together to collect and analyze information. Ultimately, CDPHE confirmed this as a confirmed waterborne disease outbreak on July 25, 2022. Four people from multiple households met the case definition of an acute onset of gastrointestinal illness. All four cases were Colorado residents, no one was hospitalized, and all individuals survived the illness.

Epidemiology and Investigation Concluded: Illness was likely Non-Shiga Toxin-Producing Escherichia coli bacteria are found in surface water, like lakes and streams. These bacteria live in the intestines of mammals, and some can cause mild to severe gastrointestinal illnesses.

Summary of Sampling and Gastrointestinal illness:

• 4 sick individuals
• 5 total coliform positive results
• 2 E. coli positive results 

Gastrointestinal Illness: 

Non-Shiga Toxin-Producing Escherichia coli infections can cause gastrointestinal illness with diarrhea and abdominal cramps, among other symptoms. These bacteria occur naturally in the intestinal tract of most animals and people, and can enter surface waters like rivers and

lakes through animal waste. When the people at Rainbow Valley Ranch drank the untreated surface water, the bacteria made them sick. 

Incident Timeline: 

• April 1, 2022
• At least one resident experienced gastrointestinal illness symptoms.
• July 20, 2022
• CDPHE received notification from a tenant at Rainbow Valley Ranch about their drinking water. According to the complainant, the landlord was using untreated lake water for the community’s drinking water and the complainant had diarrhea and blood in their stool. The complainant took a drinking water sample and sent it to the lab, where it was later confirmed as containing E. coli bacteria.
• July 21, 2022
• WQCD performed a site visit, reviewed the source (2 lakes) and treatment processes and collected total coliform samples. WQCD identified a filtration and disinfection system, but the disinfection was not connected to the water and the filtration system was not certified to remove bacteria or viruses. Chlorine results were non-detect.
• In addition, WQCD completed a population count and determined that Rainbow Valley Ranch met the definition of a public water system and would need to comply with the requirements in the Safe Drinking Water Act.
• July 22, 2022
• WQCD received lab results from the total coliform samples showing the presence of total coliform and E. coli. The division issued a boil water advisory to the system, requiring the owner to inform all residents that they must boil their water before using it.
• July 23-24, 2022
• Teller County Public Health and Environment received several other complaints from Rainbow Valley Ranch residents who were experiencing similar gastrointestinal illness symptoms.
• July 25, 2022
• Teller County Public Health and Environment interviewed residents to gather information on symptoms, onset dates, and water quality issues. CDPHE evaluated information and sample results and determined this was a confirmed waterborne disease outbreak. CDPHE required that the owner continue to post the boil water advisory and maintain a 2 ppm chlorine residual until the issue was resolved.
• August 31, 2022
• The owner of Rainbow Valley Ranch reported that she has stopped using the lakes for water and is instead hauling water from a nearby public water system.
• September 7, 2022
• WQCD issued an enforcement order and required the owner to pay a penalty, correct sanitary defects, and hire a certified operator, among other things.
• Late Fall/Early Winter 2022
• The Owner subdivided the property and sold half in order to avoid being a regulated public water system. The fine is still in effect.

➽ Tyson Ingles, Lead Drinking Water Engineer

Program Manger's Message: Draft CCR Rule Considerations

We recently published an article about the draft PFAS rule published by EPA in March 2023. EPA also published a draft rule in March 2023 to revise the Consumer Confidence Report (CCR) Rule. EPA was required to undertake this action when Congress passed and the President signed America’s Water Infrastructure Act (AWIA) of 2018. AWIA amended the Safe Drinking Water Act and required EPA to revise the CCR rule to:

• Increase the accuracy and readability of CCRs;
• Provide more information about lead;
• Require systems serving more than 10,000 people to provide CCRs twice per year; and,
• Allow for electronic CCR delivery.

EPA also decided to include a provision in the rule requiring states to provide direct compliance monitoring data to EPA as opposed to the current practice of reporting summary information and violations only. We are concerned about this provision leading to EPA micromanaging states with primacy and frequently questioning us about specific water systems that may have issues particularly with per- and polyfluorinated alkyl substances (PFAS) or lead or whatever contaminant may be perceived as a hot topic at the moment.

In reviewing the draft rule we identified some items of concern that the Association of State Drinking Water Administrators (ASDWA) highlighted in its comments on the draft rule. While EPA was certainly required by AWIA to increase the CCR frequency for large systems, specific provisions in the draft rule appear to require water systems to duplicate efforts and communications already undertaken when water systems provide information to the public as part of the Public Notice Rules. We hope EPA elects to reduce those duplicative activities. 

The draft CCR rule also placed a heavy emphasis on translating CCRs into alternate languages and requires states to assist water systems in this process. We support helping people get information they need in a language they best understand. We are happy to assist water systems in achieving this goal. However, we are concerned that the draft rule could be construed as requiring states to undertake translation services in some instances. We believe that EPA must take the lead in helping states and water systems with translation. But states should not be directly required to take on this task by EPA; doing so can create an inherent conflict of interest with states' oversight role. 

Although EPA was tasked in AWIA with improving readability, ASDWA still believes that some of the revised language, such as the nitrate and arsenic education statements, are reading at a 12th -14th -grade level, which is too high for the general public. To improve readability, EPA should simplify much of its new language to a lower reading level. 

EPA also had some concerning language in the draft rule about “misleading statements.” We agree that it is unacceptable for water systems to put misleading statements in CCRs that underplay the health risks from violation or similar circumstances. In Colorado, we review CCRs and require that misleading statements be corrected. However, EPA used an example of a misleading statement as characterizing the drinking water as “safe.” We have serious concerns about this example. Considering that the Maximum Contaminant Level Goals (MCLGs) for many contaminants are zero, we understand that many contaminants can impart a very low health risk even if below the MCL. However, we do not believe that stating the water is safe to drink when a system is in compliance is a misleading statement that must be corrected. 

The timeline for this proposed rule is also concerning. EPA plans to finalize this rule in 2024, and then have it go into effect in 2025. This is not enough time and very challenging from a feasibility standpoint. For most drinking water rules, states have two years to adopt the rule and then the compliance date is one year out from that. Specifically, this is not enough time for states to adopt the rule and attain primacy. This is also not enough time for states to develop the needed policies, guidance, and business processes to support implementation. This is not enough time for states and water systems to develop translation assistance efforts and materials needed. We hope that EPA takes a more reasonable approach to the timing of the final rule.

Lastly, this rule will also require new resources for the division to implement. Colorado has been able to implement several new rules the last decade involving disinfection, water haulers, storage tanks, backflow prevention and cross connection control, and the revised total coliform rule without adding program resources for implementation. However, with this CCR rule coming essentially at the same time as the Lead and Copper Rule Revisions (LCRR) and the PFAS rule, the division must obtain additional resources to support maintaining primacy into the future.  

As always, we will engage with stakeholders in developing the CCR rule for Colorado. We already have a very strong program with respect to public notice, the current CCR rule and translation, especially into Spanish. We will do our best to help water systems comply with the CCR rule considering our funding and resource levels. I advise you to learn about the new draft CCR rule and take steps to prepare your water system for it. 

Thank you,

➽ Ron Falco, P.E. Safe Drinking Water Program Manager

Chlorine Residual Monitoring and Pocket Colorimeters

During sanitary surveys, inspectors evaluate where chlorine residual sampling is being performed and will request to do side-by-side chlorine residual measurements with the operator. Chlorine residual monitoring is required both for entry point chlorine residual monitoring and also in the distribution system during bacteriological sampling. Public water systems that only use sodium or calcium hypochlorite or chlorine gas to form free chlorine for disinfectant residual should be monitoring and reporting free chlorine residual at all times. Conversely, any systems adding ammonia to form chloramines must monitor and report disinfectant residual as total chlorine residual. In this article, we will discuss handheld colorimeters and questions we’ve received from operators during sanitary surveys on properly measuring both high range and low range chlorine residuals. Improperly using an EPA accepted test method, using expired or incorrect DPD reagent or not verifying or operating disinfectant monitoring analytical equipment in accordance with manufacturer requirements can result in a violation of Regulation 11, Section 11.46. This was one of the Top 10 most cited violations cited during sanitary surveys in 2022.

The main issue inspectors often see in the field is measuring low range vs. high range free chlorine residual. For HACH pocket colorimeters (PCII) in the low range (LR) setting, a readout of 2.2 will flash repeatedly if the sample concentration is above 2.2 mg/L free chlorine. Recording the 2.2 mg/L as the chlorine residual is not correct and will result in a violation during a sanitary survey. The operator should be familiar with how to change their chlorine analyzer setting from low to high range. For a HACH DR300 or a HACH PCII, you must select the High Range (HR) menu option (please see your manual). For HACH units in High Range, the sample cell also changes to the plastic vial with a 5-mL sample and two 10‑mL DPD Free Chlorine Reagent Powder Pillows or two 10‑mL DPD Total Chlorine Reagent Powder Pillows must be used for each test. Please see your manual for your specific chlorine residual kit, and note that some manuals have to be downloaded online now.

Other issues that can result in field based violations for chlorine residual monitoring is using expired DPD reagent and glassware that is caked with DPD (see photo below). 

Operators must be familiar with their colorimeter and should have written maintenance procedures and a maintenance log implemented for the analyzer, including routine verifications required by the manufacturer (HACH does not specify a frequency for pocket colorimeters but CDPHE does quarterly checks with GELEX standards on our pocket colorimeters). Please note that for online chlorine analyzers used for compliance with Regulation 11, online analyzers must be verified at least once a week by taking a parallel grab sample and analyzing it by another verified method (bench top) or by comparison with other parallel analyzers (see Policy 4 Guidance). All verification checks and results should be written down in a logbook.

Please avoid these field-based violations related to chlorine residual monitoring and ensure proper disinfection by being familiar with your analyzer and following proper sampling protocol. For any questions or concerns, please email our Field Services team at cdphe_wqcd_fss_questions@state.co.us.  

➽ Connor Clarke, CWP, Field Services Section

➽ Heather Young, PE, CWP Field Services Section

Program Manager's Message: Draft PFAS Rule Considerations

We finally reached the stage where EPA is nearing the completion of the process that leads to a new drinking water rule being added to the Safe Drinking Water Act to address per- and polyfluorinated alkyl substances (PFAS). This has been a long journey, and there is still a ways to go before a rule is in place and implemented. Several years ago two PFAS compounds, PFOA and PFOS, were part of the third Unregulated Contaminant Monitoring Rule (UCMR3). We started working to address PFAS in drinking water in 2016 after we became aware of their presence in drinking water at several communities in El Paso County. Our efforts continued through the 2020 sampling project and today in implementing the updated PFAS health advisory EPA issued in June 2022.

EPA made the decision to regulate PFAS under the Safe Drinking Water Act in late 2021 and in March 2023 published a draft rule for public comment. The draft rule for PFAS establishes Maximum Contaminant Levels (MCLs) for PFOA and PFOS at 4 parts per trillion (ppt) and a novel (at least within the Safe Drinking Water Act) Hazard Index approach to address four more PFAS compounds - PFNA, PFHxS, GenX and PFBS. Of these, PHHxS which is often associated with firefighting foam has been detected most often in Colorado. During its fifth Unregulated Contaminant Monitoring Rule (UCMR5) testing EPA is again sampling for multiple PFAS compounds, so more of these may be addressed in future rule revisions. 

EPA indicated that after the public comment period on the draft rule, it anticipates finalizing the PFAS rule in early 2024. States typically have two years to adopt a final rule, and then the compliance date follows a year of initial monitoring. So the compliance date for this rule would be sometime in 2027 if the normal schedule is followed.

EPA structured this draft rule to model other chronic organic contaminants with quarterly monitoring and compliance based on a running annual average of those results. Reduced monitoring options are available. Violations of the MCL or Hazard Index would result in Tier 2 public notice. We support this approach as compared to a possible approach treating violations as an acute health risk warranting Tier 1 public notice.

There is a significant need for EPA guidance on this rule that addresses treatment design and conduction pilot studies, residual waste handling and disposal, reduced monitoring and the trigger level, public notice and communications and much more. This is very important to foster state implementation and water system compliance. 

We believe that there are many feasibility concerns associated with addressing PFAS contamination in drinking water generally, and these become even more challenging with MCL values set at the practical quantitation limit that many laboratories can reliably achieve. Although the laboratory Colorado has been using can get lower values than the MCLs, this one laboratory will not be able to serve all the water systems that need to test. Lab capacity could become a significant problem, and the turnaround time to obtain results could also become very slow.

This rule will also require significant new resources to implement. Colorado has been able to implement several new rules the last decade involving disinfection, water haulers, storage tanks, backflow prevention and cross connection control, and the revised total coliform rule without adding program resources for implementation. However, with this PFAS rule coming essentially at the same time as the Lead and Copper Rule Revisions (LCRR) and the Consumer Confidence Rule (CCR) revisions, the division must obtain additional resources to support maintaining primacy into the future.  

In addition to feasibility concerns with laboratory capacity and program resources, financial resources for water systems to secure compliance will also be needed. The State Revolving Fund and Bipartisan Infrastructure Law have provided a boost, but this will not be enough funding for all the needed projects. These funding sources help with initial design and construction activities, but do not help with the long-term operating and maintenance costs. For PFAS, residual handling and disposal costs are likely to be high, and these costs will need to be borne by water utilities and ultimately rate payers. Small systems will face special challenges with the costs and need for higher operator certification levels if treatment needs to be installed. 

As always, we will be engaging stakeholders in developing the PFAS rule for Colorado. Fortunately, we have many staff that are experienced with PFAS that understand the issues and challenges, and have been helping water systems address contamination. This will enable us to identify assistance, policy and training needs. We will strive to help water systems meet the requirements of the PFAS as best we can considering our funding and resource levels. Our goal will be to get as many systems as possible into compliance before the required deadline. I advise you to learn about the new draft PFAS rule and take steps to prepare your water system for it. If you have not yet collected PFAS samples from your system, I advise you to contact us and we will test your water for free. Getting in front of this now while funding is available is the best approach to keeping tap water safe for your customers. 

Thank you,

➽ Ron Falco, P.E. Safe Drinking Water Program Manager

Lessons Learned - Weld county legionella cluster

What Occurred?

In November and December of 2022, the Weld County Public Health Department consulted with CDPHE about an unusual number of cases of Legionnaires Disease occurring in a relatively small area. There were five reported cases of the illness and case interviews were completed for four of the five affected people. Excerpt from the internal communications at the time:

"We have recently seen a notable increase in reported legionella infections in Weld County – five cases in the last 12 days. Of the three most recent cases, two live within two miles of each other and one lives within seven miles of the other two. We have not yet found any evidence of linked exposures."

In a situation where a cluster of illnesses is identified and there is a potential for the root cause of the illness to be drinking water, public health partners work with the Safe Drinking Water Program here at CDPHE to assess the likelihood/possibility that the drinking water is the root cause of the cluster (or waterborne disease outbreak).

What was the Response?

Based on initial interviews with the ill folks, the county determined that there appeared to be a lack of common exposures that are usually seen. Typically in a legionella outbreak, you may find that all infected people used the same recreation center hot tub or shop at the same grocery store that has vegetable misters running. 

The county and state epidemiologist group then reached out to the Safe Drinking Water Program staff to check the known addresses of the ill people to see if they were served by the same water system and if it was possible that a contamination event had occurred at that specific water system. We specifically were trying to determine whether there had been any service disruptions, major construction projects, water main breaks, or other events related to the water utilities that service these individuals' residential areas. 

The Safe Drinking Water Program then interfaced with water system operational staff to confirm whether there had been any water quality issues in these areas. Also, it was determined that these homes- while being in proximity to each other, were served by four different water providers. All providers demonstrated robust chlorine residuals and were able to show a lack of bacteriological contamination in their drinking water.

While the specific cause of this outbreak was never determined, public drinking water was eliminated as a source.

What can a water operator do to prepare for such an event?

If a cluster of illnesses occurs in your service area, you may be called upon to produce records of treatment and distribution system water quality in order to eliminate any potential that your drinking water caused the illnesses. 

Maintaining treatment plant records is standard procedure for most public water systems.  However, having a comprehensive distribution system microbial sampling that goes beyond the minimums of the total coliform rule is more rare. Consider developing water quality sampling starting with distribution system basic water quality parameters like chlorine residual, pH, turbidity and heterotrophic plate count. This will help provide assurance that your distribution system water quality is not the cause of a legionella outbreak. Also, water sampling for legionella can be done on a quarterly or semi-annual basis to provide further assurances to the public that the drinking water quality you provide to your customers is safe and relatively pathogen free. 

➽ Tyson Ingles, Lead Drinking Water Engineer