Acute Health Risks - Can it happen to you?

The below article is a re-run and update from an article published in the 2007 Summer Aqua Talk newsletter. Since then, the water sector has navigated many acute and emergency situations in partnership with the WQCD. We value your continued partnership and vigilance as you protect the public health and environment for our communities. 

We could all learn a little something from the Boy Scouts, especially when it comes to acute health risks in drinking water systems. Acute health risks that must be reported can be caused by events such as:

• Acute total coliform maximum contaminant level violations (when fecal or E. Coli is present);
• Failure to collect repeat samples after a fecal or E. Coli positive sample;
• Failure to test for fecal or E. Coli in a total coliform positive repeat sample;
• Nitrate, nitrite or total nitrate nitrite maximum contaminant level violations;
• Failure to take nitrate or nitrite confirmation sample within 24 hours after receipt of the first sample showing exceedance of the maximum contaminant level;
• Surface water treatment rule violations, such as not using a filter cartridge, not feeding coagulant, or a single exceedance of the maximum allowable turbidity limit or failure to maintain chlorine level entering the distribution system; etc).
• Suspected waterborne disease outbreak;
• Situations such as depressurization of a distribution system due to a line break or loss of power;
• Uncontrolled cross connections that contaminate the water supply;
• A treatment or supply emergency (for example, failure or significant interruption of key water treatment processes, a natural disaster that disrupts water supply, chemical spill or unexpected loading of pathogens);
• Tampering or vandalism that could have contaminated the water supply

Preparing for these situations can save lives, not to mention save you time and money. To help you keep your cool in a stressful situation, consider preparation measures such as:

• Plan: Gather necessary forms and phone numbers, including the 24-Hour incident reporting hotline (877) 518-5608. 
• Be familiar with the Public Notice wizard to create public notice templates and think through possible acute situations.
• Designate people responsible for specific activities, make sure your Operator Delegation Plan is up to date.
• Practice with benchtop exercises/drills. Use this coaching request form to request a  Local Assistance Unit benchtop exercise for your facility.

If your system has experienced tampering or suspected tampering, including a cyber attack, you are required to notify the Colorado Department of Public Health and Environment immediately. For details, see section 11.2(1) of the Colorado Primary Drinking Water Regulations and visit the Drinking Water Security Response Toolbox. Report physical and cyber security incidents to the WQCD Tampering Threat and Incident Report Form. 

For more information about acute procedures, please check Drinking Water Policy DW-0001 Response to Acute Health Threats from Public Water Systems, the Pressure Loss and Main Break Guidance and the Drinking Water Emergency information website.

CoWarn, the statewide Water/Wastewater Agency Response Network (CoWARN) of utilities helping utilities to prepare for the next natural or human-caused emergency is also a resource to help public water systems.

By being prepared, water suppliers can effectively handle emergency situations and potential acute situations to protect public health. 

➽ Heather Young, PE, CWP, Field Services Section Section Manager 

➽ Emily Clark, Drinking Water Enforcement Unit Manager

Legionella Bacteria and Drinking Water Disease Outbreaks

I attended the American Water Works Association’s (AWWA’s) Annual Conference and Exposition (ACE) in Denver, Colorado, earlier this year. There were some excellent sessions on a wide variety of topics. However, the session that stood out the most to me covered Legionnaires'  Disease and drinking water. Presenters include Dr. Mark Lechavellier, Dr. Chad Seidel, Sheldon Masters, and Julie Kennedy. The session covered some of the latest research into Legionella and drinking water, plus a case study regarding an outbreak in Grand Rapids, Minnesota, that occurred from 2023 to 2024.

Although there are over fifty Legionella species and about half can cause disease, Legionella pneumophila is the most important because it causes most Legionnaires' disease cases and occurs naturally in aquatic environments. The species can infect free-living Amoeba, where the amoeba can act as a host for Legionella. The 1989 drinking water Surface Water Treatment Rule (SWTR) set a treatment technique for Legionella and established a Maximum Contaminant Level Goal (MCLG) equal to zero. Groundwater systems have no such treatment technique requirements, but one-third of the outbreaks occur in groundwater systems. Partly due to better reporting and testing, Legionella cases rose 10-fold from 1990 to 2021. Legionnaires’ outbreaks often occur in buildings such as hotels, medical facilities, and offices. People catch Legionnaires’ disease by inhaling small droplets of water suspended in the air containing Legionella. Legionnaires’ disease does not spread from person to person.

Dr. Lechavallier reported on a Legionella occurrence study that involved water testing 57 utilities. Overall, 9,118 samples were collected, and 1.2% (109) were positive. Thirty-two percent of utilities had detections. A chlorine residual of at least 0.4 mg/L dramatically reduced the positive detection frequency. Dead-end water lines, low water usage, and tank sediment raised the risk of finding Legionella. Flushing can be effective in reducing Legionella levels. Optimum Corrosion Control Treatment (OCCT) reduces pipe corrosion, which reduces the habitat where Legionella can grow. The study concluded that while eliminating Legionella is impossible, testing and management are feasible. Communicating with commercial and industrial customers about Legionella can also be beneficial. 

Unfortunately, Grand Rapids, Minnesota, experienced a severe Legionella outbreak from 2023 to 2024. Grand Rapids has a population of 11,000 and uses groundwater from five wells. The community did not disinfect and had three storage tanks (0.5 million-gallons each) and 81 miles of distribution system. Increased disease incidence began in mid-2023, but water was not believed to be the cause at that time. Legionella were not found in the water system, but the bacteria were found in the water in buildings with Legionnaires’ Disease cases. Over the next year, there were 34 total cases with 30 people hospitalized and two fatalities. After a complete assessment and expert assistance, including Dr. Seidel, chloramination started in June 2024. There have been no Legionella cases in Grand Rapids since then. Considerable effort also involved working with building owners in the town. Generally, buildings that maintain and actively implement water quality management plans do not have outbreaks.

EPA is in the process of updating its rules addressing Microbial Pathogens/Disinfection Byproducts (M/DBPs). It will be a few years before the update is finalized, and these rules will still not apply to groundwater systems. The updated rules are likely to improve the treatment technique requirements for Legionella at surface water systems. While we believe that Colorado is well-positioned to implement improvements due to our rules covering disinfectant residual, storage tanks, and cross connection control (backflow prevention), the occurrence data in this study are concerning. Additionally, even with solid operations by water utilities, important work involving water quality management plans within buildings is not part of our oversight. We encourage utilities to learn more about Legionella and consider partnering with their commercial and industrial customers, especially health facilities like hospitals and nursing homes, to take steps that could reduce the likelihood of a Legionnaires’ Disease outbreak in Colorado.  

As always, thank you for keeping our drinking water safe.

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

➽ Co-Author Chelsea Cotton, P.E. Lead Drinking Water Engineer

Program Manager Message: An Open Letter to the Drinking Water Community - An Opportunity to Say THANK YOU!!!!

Hello everyone, 

In the May 2008 issue of Aqua Talk we ran an open letter of thanks to the drinking water community after the waterborne disease outbreak in Alamosa, Colorado. We have not had a waterborne disease outbreak at a public water system in Colorado in the 17 years since. We thought it would be a good time to rerun this article as a reminder of what happened and how the water utility community came together in response. We have had some disease outbreaks from drinking water, but they have happened in buildings or other situations that did not involve regulated systems. The Alamosa event was the first use of the Colorado Water and Wastewater Response Network (Co-WARN), which has been used many times since 2008 by utilities in need, and those needs have been met by other utilities. So, I say again - THANK YOU!

Article from May 2008: 

In March, the Water Quality Control Division in conjunction with numerous emergency response agencies and city of Alamosa officials were deeply involved in responding to a waterborne disease outbreak within the community. While a definitive identification of the cause has not yet been determined and investigative activities are ongoing, I want to take this opportunity and use this forum to tell everyone involved...Thank you!!

The city of Alamosa and the division could not have accomplished what they did without the assistance and dedication of all the agencies, groups and individuals involved with this response. The request for resources was placed to public water systems though our COWARN network, and the response was overwhelming and immediate. As new resource needs were identified, requests were made, and the resource materialized. Events and circumstances constantly evolved, and the response of the drinking water community was unwavering.

The boil/bottled water order was in place for 23 days and had an impact on the entire community of approximately 9,000 citizens. A staggering amount of work was accomplished within those 23 days including the following:

• An evaluation of the distribution system, including a review of potential cross­ connections.
• A multi-staged systematic disinfection and flushing of the storage tanks and entire 49 miles of distribution piping.
• Extensive monitoring for a number of water quality parameters throughout the distribution system including Salmonella, total coliform, Giardia, cryptosporidium, arsenic, lead and copper, and chlorine residuals.
• The Consumer Protection Division worked with restaurants and other businesses to keep many of them operating during the event.
• Bottled water and bulk water was distributed to residents.
• Communications personnel made substantial public notice efforts with the media to keep people informed.

The drinking water community should be proud of its response.

➽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

Microbial/Disinfection Byproducts (M/DBP) Federal Rule Update

Note: this article is part 2 of a series to read part one, please visit the Aqua Talk article posted on March 9, 2022

In 2020 EPA began stakeholder engagement as part of its review of Microbial/Disinfection Byproducts (M/DBP) Rules. The M/DBP rules are an important suite of drinking water rules designed to protect the public from the acute risks associated with waterborne disease outbreaks by requiring strong treatment and disinfection. However, the rules also try to balance the chronic health risk associated with cancer from certain disinfection byproducts. The Safe Drinking Water Program (program) engaged in this process and shared some of our thoughts and experiences with these rules.

In a prior Aqua Talk Article we briefly shared our overall input to EPA on a variety of topics including evaluating sources of drinking water that could be Groundwater Under the Direct Influence (GWUDI) of surface water and disinfection treatment evaluations, risks associated with storage tanks and our approach to requiring disinfection residual throughout distributions systems in Colorado. EPA asked us to provide more detailed information regarding our experience with preventing microbial contamination with focus on disinfection, storage tanks and cross connections. In this article we summarize the input provided. 

The Alamosa waterborne disease outbreak in 2008 catalyzed our efforts to reduce exposure to pathogens in tap water. Alamosa had deep wells and no disinfection in place while serving 8,900 people. One thousand three hundred (1,300) people were estimated to have been sick during the outbreak. Twenty people were hospitalized and one person died. Twenty six (26) percent of those that were ill reported symptoms lasting a year and a half later. It was also estimated that 40 percent of the infants in town got sick. In addition, the outbreak caused severe impacts to the economy, and numerous businesses closed. While the cause of the outbreak was most likely animal waste entering cracks or holes in a storage tank, calculations showed that it likely took very little waste to contaminate the entire water system. Thankfully Alamosa has since made improvements to their water system and now provides adequately disinfected drinking water and continues to work to ensure the safety and health of consumers. However, with our goal to minimize waterborne disease risks statewide, we tackled disinfection and backflow prevention in addition to storage tanks.

Beginning in 2014, the program worked with stakeholders to address these issues in our Colorado Primary Drinking Water Regulations (Regulation 11). Key changes to regulations involved:

• Modified disinfection rules drastically reducing waivered systems
• Implemented minimum disinfectant residual of 0.2 mg/L
• Developed special rules for hand-pumped systems and water haulers
• Developed a special rule requiring routine and comprehensive storage tank inspections
• Updated and improved cross connection control rules

We shared with EPA some of the key results we have seen because of these changes, and will share some of that here.

Regarding disinfection waivers, the program has been regularly and thoroughly reviewing disinfection waivers and withdrawing waivers where needed, especially in response to positive total coliform or E. coli results in finished water. The chart below shows the number of public drinking water systems waivers has declined since 2007. By the end of 2022, we expect that there will only be two active disinfection waivers in Colorado. Overall, we believe that this decline in disinfection waivers better protects public health as the added pathogen contamination barrier of continuous disinfection is in place.

For the storage tank rule, we have about 1,400 storage tanks in the state subject to this rule. From April 2016 to August 2020, we issued about 300 violations of the storage tank rule and identified about 400 significant deficiencies involving storage tanks. Some of the specific items observed have included dead rodents in tanks as well as live snakes, and bullet holes. The most common concerns involve issues with hatches and vents. The good news is that well over 90% of these issues have been resolved. We believe this represents a significant improvement in risk reduction associated with storage tanks in Colorado as a result of implementing this rule.

We updated and/or developed handbooks related to water haulers and public water systems that operate primarily hand-pumped wells to include disinfection and operational practices. We also require that disinfectant residual in distribution systems be monitored and reported to the division. If values fall below 0.2 mg/L, then a treatment technique violation requiring tier two public notice can result. We also strengthened our ability to oversee the cross connection control rule and required that distribution systems be specifically surveyed for cross connections. Since 2016, hundreds of cross connection deficiencies and violations have been identified and corrected.

We believe that the overall risk reduction resulting from these efforts has been substantial. We have not had a waterborne disease outbreak at an active public drinking water system in Colorado since 2008. But waterborne disease outbreaks are tricky to confirm, so we also look at the number of E. coli violations. We think that looking over the course of decades is best to observe trends. Below are two charts showing both waterborne disease outbreaks and E. coli violations over the last few decades. As you can see, these trends show very positive results! 

This information was shared with EPA in 2021. We do not know exactly how EPA will use this information or the ultimate direction they will take with updating the M/DBP rules. We will keep you informed, and obviously you will have the opportunity to engage with EPA in this process as well. It will be the mid-2020s before EPA fully updates the M/DBP rules, but these are highly impactful rules and we encourage water systems to be aware of and engaged in the process. Thank you.

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

Reporting Waterborne Disease Outbreaks

Cooperation between water systems and healthcare facilities within their service areas can help prevent waterborne disease and detect potential outbreaks early to minimize harm. The following information outlines the basics for how to recognize and report waterborne disease outbreaks (WBDOs). 

What are waterborne disease outbreaks?

Waterborne disease outbreaks (WBDO) can be categorized by etiologic agent (the organism making people sick), type of water use (drinking, recreational, other), routes of entry (ingestion, inhalation, intranasal, or skin contact) and means of water contamination.

WBD agents may cause gastrointestinal, skin, respiratory or systemic illness. Symptoms may include abdominal cramps, vomiting, diarrhea, hives, rashes, irritated eyes, sore throat, pneumonia, or systemic illness.

Purpose of Reporting and Monitoring

• To detect WBDOs that can be controlled with appropriate public health measures (boil or bottled water advisory, pool closure). 
• To confirm the type of WBDO, thereby guiding treatment and control measures to prevent further exposures and additional cases of illness. 
• To assess whether implemented control measures are effective in stopping further transmission.
• To expand current understanding of the transmission, pathogenesis, and community impact of illness caused by WBD agents. 
• To identify new WBD agents, hazards, or gaps in the water safety system.

Responding and Reporting

What actions can health facilities take?

In most instances, consult with state/local environmental and public health staff, who can provide situation specific guidance and assist an owner/operator in treating water and cleaning the facility as needed.  With guidance from environmental health staff, immediate control measures could include (but are not limited to) the following:

• Drinking water: Issuing a boil or bottled water advisory, recalling a commercial product like bottled water
• Recreational water: Closing a facility or beach, posting warning signs at a lake, super-chlorinating pool water, backwashing the filter, draining the water, sanitizing the bathrooms or other likely-contaminated areas, cleaning the entire facility, and refilling the water and treating the water as required or feasible (for treated water facilities)
• Any water source: Issuing a press release to advise citizens who may develop illness

How to report the event?

• Water systems and local public health departments: Report known or suspected WBDO to CDPHE immediately upon receiving a report of a known or suspected outbreak. CDPHE will review the situation with you and assist if there is agreement that an investigation is needed.
• Health care facilities: Immediately notify your local health jurisdiction of outbreaks or suspected outbreaks.
• Per statute 6 CCR 1009-1, appendix A: "Outbreaks - known or suspected of all types - including those transmitted from food, water, person-to-person, and related to a healthcare setting." 

Who to contact at the department?

• Contact the department’s 24-hr emergency line: 1-877-518-5608. 
• Call as soon as possible but no later than 10 a.m. of the day following the incident.
• CDPHE Communicable Diseases
• 303-692-2700
• 303-370-9395 (after hours only)
• CDPHE Toxicology Line
• ToxCall 303-692-2606, cdphe_toxcall@state.co.us
• ToxCall is a good resource if toxic algae is suspected

Additional details including what information to include when you report an incident and what to expect after reporting can be found here.

➽  Chelsea Cotton Source Water & Emerging Contaminant Engineer