Upcoming Perchlorate Rule

Program Manager message:

Colorado’s Safe Drinking Water Program is not the only such program in the United States with a newsletter. Over the years, I have subscribed to a few of these newsletters, and sometimes we have reprinted or used articles from them with permission. In this case, I recently read an excellent article in the Arkansas Drinking Water Update newsletter regarding EPA’s proposed perchlorate rule. I reached out to my counterpart in Arkansas, Lance Jones, who authored the article and gained his permission to reprint it here. We are also adding a Colorado perspective regarding likely perchlorate rule impacts on Colorado’s public water systems. 

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

EPA Proposes Perchlorate Rule

On January 2, 2026, the Environmental Protection Agency (EPA) issued a proposed Rule under the Safe Drinking Water Act to regulate perchlorate (ClO4-) in drinking water as part of the National Primary Drinking Water Standards.

The proposed Rule includes a Maximum Contaminant Level Goal (MCLG) of 20 micrograms per liter (ug/L). EPA is also co-proposing enforceable Maximum Contaminant Levels (MCLs) of 20 ug/L, 40 ug/L, or 80 ug/L for perchlorate and will apply to community and non-transient public water systems.

Initial monitoring consists of quarterly monitoring or semi-annual for small ground water systems, for a 12-month period, with routine monitoring determined by those results. Systems with a running annual average above the MCL require quarterly monitoring, systems less than the MCL but greater than or equal to 4 ug/L require annual monitoring (surface water) or triennial (ground water) monitoring, and every 9 years for systems less than 4 ug/L. 

Perchlorate has had a back-and-forth regulatory history for the past 25+ years. Starting with including perchlorate levels in drinking water systems under the 1999 Unregulated Contaminant Monitoring Rule (UCMR). The results led to a 2011 decision by EPA to regulate perchlorate in drinking water. EPA proposed a Rule to regulate perchlorate in drinking water in 2019. In July 2020, EPA withdrew the determination to regulate perchlorate. A legal challenge of the decision to withdraw was filed and led to a 2023 court decision to vacate the withdrawal. EPA entered into a consent decree to sign and issue a final Rule to regulate perchlorate in drinking water by May 21, 2027.

Perchlorate is commonly used in solid rocket propellants, munitions, fireworks, matches, signal flares, and vehicle airbag initiators. It has also been associated with some imported fertilizers and trace amounts can result from improper handling and degradation of hypochlorite solutions.

Perchlorate can potentially interfere with the thyroid gland hormone production. Changes in thyroid hormone production in pregnant women are associated with adverse neurodevelopmental effects in their children. Thyroid hormone level changes at other life stages can lead to hyperthyroidism, developmental outcomes, and cardiovascular system impacts.

EPA’s data show that perchlorate is not widespread in drinking water systems and EPA expects less than 1,300 of the over 135,000 regulated water systems nationwide to find perchlorate levels above the proposed limits. For systems that do find elevated levels of perchlorate, treatment options include ion exchange, biological reduction, reverse osmosis, and blending with another source.

The sampling of several Arkansas water systems in 2001 and 2002 found no detects of perchlorate. ASD will add sampling of perchlorate to the current compliance monitoring efforts upon EPA promulgating a final Rule.

More information about perchlorate in drinking water can be found on the EPA website at:

https://www.epa.gov/sdwa/perchlorate-drinking-water#proposed-perchlorate

➽ Lance Jones, P.E. Health Program Administrator, Arkansas DPHP Environmental Health Engineering

Listening to the Certified Operators: Updates on the Operator Certification Experience

 

In 2025, the Water and Wastewater Facility Operators Certification Board (WWFOCB) issued a survey to the water sector to learn about your experience with the certification exam process. We’ve heard your feedback, and we want to ensure you have the most up-to-date information on the changes and resources available to you.

Enhancing Accessibility and Efficiency

We are committed to making the certification process as smooth and inclusive as possible. To that end, we have implemented several key updates:

• Spanish Language Exams: As of August 2025, both Class D and Class 1 examinations are available in Spanish. Operators can request this option during the scheduling process with PSI.
• Application Turnaround: We know you're eager to get to work. Between June 2024 and May 2025, our team reviewed 5,965 applications. We are proud to report that 91% of all applications were reviewed in less than 10 days.

Evolving the Exam Process

The Board recently revised Regulation 100 to better balance workforce entry with high professional standards.

Important Change: The eligibility period for retaking an exam has been shortened

 from 180 days to 100 days.

This change allows for three testing attempts under a single application while ensuring operators take sufficient time to study and prepare between tries. Our goal is to ensure the program produces quality operators, not just good test-takers.

Resources and Support

We understand that preparing for exams can be daunting. To help, we recommend utilizing the Need-to-Know Criteria on the WPI website. However, please ensure you are using the correct versions; Colorado operators should not use the new 2025 criteria yet, as they are not currently aligned with the exams our state administers.

If you run into trouble, knowing who to contact can save you a lot of time:

Looking Ahead

We are currently working on a public matrix of approved roles and narrative job descriptions to clarify experience categories. We also recognize the interest in partial credit for related backgrounds (like military or lab experience). While current regulations do not allow for this, we are exploring the regulatory changes that would be required to make it a reality.

Your feedback continues to shape how we serve the operator community. Thank you for your continued professionalism and for being the backbone of Colorado's public health.

➽ Kyra Gregory, Local Assistance Unit Manager

Partnering for public health during Drinking Water Week

Governor Jared Polis has proclaimed next week, May 3-9, as Drinking Water Week in Colorado. The Colorado Department of Public Health and Environment will observe the week with the theme, "Clean, accessible drinking water is a pillar of community and public health."

As drinking water providers and key stakeholders, you are the foundation upon which this pillar rests. This annual celebration is an opportunity to remind Colorado residents and leaders that the ability to simply turn on a drinking water tap is a modern achievement, one that requires continued vigilance and investment.

Providing reliable, high-quality drinking water is an essential service that underpins the quality of life for every community in Colorado, and it is tied directly to the dedication of water professionals. From source water protection to advanced treatment and robust distribution, your work ensures high-quality water reaches every home and business. Take time during Drinking Water Week to celebrate your expertise and inspire greater public appreciation for drinking water.

The department created a commemorative bookmark for the observance week. The printable bookmark and other Drinking Water Week materials are available on our 2026 Drinking Water Week web page.

We encourage our partners to join in this effort. The department will post content on Facebook and Instagram throughout the week. By sharing our posts and promoting your own local successes, we can work together to ensure that every Coloradan understands the value of their water source and the crucial role you play in delivering a safe and reliable supply. For more information about Drinking Water Week, visit the American Water Works Association website.

➽ Lilie Waterman, Marketing and Communications Specialist

Tracking Progress: Design Review Project Status and the Importance of RFI Timelines

The Engineering Section supports the WQCD mission by ensuring drinking water and domestic wastewater infrastructure is safely designed and operated. To help stakeholders navigate the review process for drinking water and domestic wastewater projects, we are highlighting our online tracking tools and the importance of timely responses to Requests for Information (RFI).

Enhanced Project Visibility

The Engineering Section maintains a public-facing Project Status Page that tracks every design application currently in our system. This tool is designed to give you full visibility into your submittal's journey. By using this page, you can identify:

• Your Review Team: Quickly identify the assigned Review Engineer and the Quality Control (QC) Engineer for your specific project.
• Active Projects: See which projects are currently under review by our engineering staff or if we are waiting for more information from the applicant.
• Backlog/Awaiting Payment: Projects only enter the backlog once invoices are paid (if applicable). These are queued and awaiting staff availability.
• Historic Projects: This includes a record of projects that have been completed, closed, or canceled.

By checking these status updates regularly, you can better estimate your project’s timeline and ensure the "ball" isn't accidentally left in your court.

Why Timely Responses Matter

A critical part of the technical review is the Request for Information (RFI), which our engineers use to seek clarification or additional details to ensure the design meets Department Design Criteria.

To keep our review queue accurate and focused on construction-ready projects, we are implementing a new administrative update:

• Important: If a project remains in an "Awaiting More Info" status for more than 120 days without communication, the project will be flagged and may be closed out in the future.

What this means for you:

• Project Closure: If an RFI goes unanswered for over four months, the project will be flagged for potential closure. Additional communications will be sent to the applicant alerting them of the need to respond.
• The Resubmission Requirement: If a project is closed, it cannot be "reopened." To move forward, the applicant must resubmit a new design application, which includes paying new application fees (if applicable) and restarting the review at the back of the current queue.
• Stay Updated: We will always notify entities before closing a project for lack of response, but the best way to avoid delays is to respond to RFIs as soon as possible.

Keeping the Queue Moving

Responding promptly helps us all. Idle projects make it difficult to forecast workloads and assign resources to those ready for construction.

Our ask to you:

• Check your status: Regularly visit our Project Status Page.
• Respond Promptly: Aim to address RFI comments as soon as they are received.
• Stay in Touch: If you anticipate a delay in responding to an RFI, contact your assigned reviewer to keep the Department updated.

We value your partnership in protecting Colorado’s water resources. Let’s work together to keep the application process flowing smoothly.

➽ Clayton Moores, Engineering Section Manager

New Limited Series Training: An Introduction to the New Monitoring Schedule Tool

Are you experiencing difficulties with the updated Monitoring Schedules? Do you need some assistance understanding and using this essential tool? The Local Assistance Unit will be hosting FREE training sessions focused on navigating the new Monitoring Schedule webpage and its associated tools. Participating operators can earn up to 0.1 training units. 

This webinar will cover:

• A general overview and associated resources
• Navigating and printing your Monitoring Schedules 
• Troubleshooting, tips & tricks

You can register for this FREE training by clicking on one of the available dates below and filling out the associated registration form. After registering, you will receive an email with information on how to access the course. 

This training opportunity will only be offered for the following sessions:

Dates and Registration	Time (MST)
April 21, 2026	12 - 1 PM
May 11, 2026	11 AM - 12 PM

Please contact us with any questions at cdphe.wqdwtraining@state.co.us.

For other training opportunities and resources, please visit our website: Training opportunities

➽ Elicia Vigil WIIN Program Coach 

Coming Down The Pipe: More Wastewater Content on AquaTalk!

Since 2019, the Aqua Talk blog has been a hub for the Water Quality Control Division (WQCD) of the Colorado Department of Public Health and Environment (CDPHE) to relay important information to drinking water operators, decision makers, and system representatives. 

The WQCD will now seek to broaden those efforts by also making sure this space is an information hub for wastewater professionals as well! 

With that in mind, we wanted to provide the following resources and updates from the Clean Water Program:

• A tutorial has been created for applying for the Domestic Discharges to Surface Water Permit. We realize the permit application can be complex, so last year we contracted Indigo Water Group to create this tool to help applicants better understand the application’s complexities. This should help make applications more complete and correct, leading to fewer issues for stakeholders. 
• WQCD has contracted with CRWA to develop and deliver test prep and cyber/physical security trainings free of charge to water professionals. Check their site for upcoming announcements on when these trainings will be scheduled and where at https://crwa.net/! 
• The WQCD offers Quarterly Clean Water Webinars (Clean Water being the half of the division that deals with waste water, storm water, ground water, surface water, etc). These webinars are open to the public and the next one is scheduled for Thursday, Apr. 16, 2026, 11 a.m. to 1 p.m.
• The Division’s Local Assistance Unit (LAU) has expanded to include a Clean Water Coach, Joe Sturgeon (joseph.sturgeon@state.co.us). He delivered the Wastewater MRT at the CRWA Conference in March and will be working with the Rocky Mountain Section of the American Water Works Association (RMSAWWA) over the next few months to deliver talks on Operator Ethics at their Action Now events. If you're interested in attending check their website at https://www.rmsawwa.org/action-now to see if an Action Now event is coming to a town near you!

Please keep watching this space for more information that’s geared towards wastewater systems! We’ll have more information available on trainings and other goings on at the division soon. 

➽ Joe Sturgeon, Clean Water Training Specialist, Local Assistance Unit

Deep Dive into Water Disinfection: Keeping Water Safe

Colorado requires all public drinking water systems to have continuous chemical disinfection, except for two suppliers that meet strict standards to retain disinfection waivers and hand-pumped wells at campgrounds. Continuous disinfection is part of a multi-barrier approach to ensuring safe drinking water is available to your consumers.  

Disinfection of drinking water inactivates (i.e., kills or prevents pathogens from replicating) waterborne pathogens, such as bacteria and viruses. The amount of microorganisms needed to cause an infection varies widely between pathogens. The median infectious dose for Salmonella typhosa is 1,000,000 organisms (but can be much less for infants), Hepatitis A virus is between 10-100, and Giardia lamblia and Cryptosporidium are less than 10 organisms. Disinfection does not completely eliminate all living organisms in the water, but does significantly reduce potential acute waterborne disease risk. The pathogen risk reduction is expressed in terms of “log inactivation”. For example, a 3.0 log inactivation value means that 99.9% of microorganisms of interest are inactivated. 

Disinfection can be accomplished using either chemical oxidants, such as free chlorine, chloramines, or ozone, or by photo-inactivation with ultraviolet light. Most Colorado water systems use free chlorine as their main disinfectant. Disinfection with chlorine or chloramines provides a persistent disinfectant residual in the distribution system. This disinfectant residual can provide defense against harmful organisms that enter the distribution system through backflow events, pipeline leaks, low pressure events, or other contamination pathways. 

Regulation 11: Colorado Primary Drinking Water Regulations requires that systems maintain a minimum disinfectant residual concentration of 0.2 mg/L at the entry point and 0.2 mg/L in the distribution system. These two requirements are the same for groundwater (GW), groundwater under the direct influence of surface water (GWUDI), and surface water (SW) systems. Each source type has additional disinfection requirements outlined below: 

• GW sources are considered protected groundwater and are expected to have limited or no pathogens. GW systems must comply with the Groundwater Rule through either triggered source water monitoring in the event of a total coliform positive sample or by certifying that the GW treatment process always provides 4-log (99.99%) inactivation of viruses. 
• GWUDI and SW sources likely have pathogen sources in the water (e.g., beavers, point discharges). Pathogenic organisms are expected and GWUDI/SW systems must meet pathogen log removal/inactivation requirements in the Surface Water Treatment Rule (SWTR). The required treatment is based on three target pathogens:
• Cryptosporidium: 2-log (99%) removal. 
• Higher levels may be required based on LT2 source water monitoring.
• Giardia lamblia: 3-log (99.9%) removal/inactivation.
• Viruses: 4-log (99.99%) removal/inactivation. 

For SW/GWUDI systems: filtration and disinfection are two complementary critical barriers for protecting public health. Drinking Water Policy 4 outlines the removal credits for various filtration types (e.g., conventional filtration, direct filtration). The disinfection treatment must be designed and operated to provide any remaining log inactivation required in the SWTR. These processes work together to ensure that drinking water is safe for the public. 

Next time, we will discuss disinfection log inactivation and the critical parameters for design and compliance demonstration. 

Below are some resources that will give more specific information about the requirements outlined above. If you have questions, please contact Melanie Criswell at melanie.criswell@state.co.us. 

Resources

• Quick guide: Disinfectant residual 
• Quick guide: Minimum disinfection for groundwater 
• Drinking Water Policy 4 (DW004): Surface water treatment rule performance assessment, proper operation and fostering improved operations
• ​Drinking Water Policy 4 - Policy guidance
• Additional information about disinfection is available at the division's Revised Total Coliform Website

➽ Melanie Criswell - Lead Service Line, Corrosion, and Emerging Contaminants Engineer