Washington Dental Water Quality - What You Need to Know
Washington State maintains expanded regulations for dental unit waterlines that every dental professional should understand. These rules are designed to ensure patient safety and align with national best practices. Agenics Labs is here to help you meet every requirement with ease.
Summary
Water used in nonsurgical procedures must meet EPA standards (≤500 CFU/mL).
All waterlines must be tested quarterly—pooled or individually—with documentation.
Immediate remedial action is required if water quality fails.
Waterline records must be kept for 5 years.
Practices must maintain infection control policies and annual training.
Understanding Rule WAC 246-817-660
WAC 246-817-660 was filed on 12/23/20 and became effective on 1/23/21, requiring dental practices in Washington must ensure that water used in nonsurgical procedures meets EPA drinking water standards of ≤500 CFU/mL. Testing must follow manufacturer guidelines or occur quarterly if none are provided. All waterlines must be tested, either individually or pooled (up to 10 lines), with equal volumes. Documentation must contain number of lines tested, whether pooled or individual, a log including dates of testing/maintenance, name of person(s) conducting testing, or a report from an indepedent testing entity. All records must be kept for 5 years.
WAC 246-817-615 adds administrative requirements: A licensed dentist must develop and maintain written infection prevention policies tailored to the services provided in the office. These policies must be reviewed annually with all practitioners, and documentation of the review must be retained for five years. Additionally, each practitioner—including dentists, hygienists, and assistants—must complete one hour of infection prevention education annually from a qualified provider. Practitioners are responsible for personally maintaining records of this training for five years.
Why It Matters
Dental unit waterlines are highly susceptible to biofilm formation, which can harbor dangerous pathogens such as Legionella, Pseudomonas aeruginosa, and nontuberculous Mycobacteria (NTM). These microorganisms thrive in the long, narrow tubing and low-flow conditions typical of dental units, especially when water stagnates between uses. The CDC has issued a national Health Alert Network advisory (HAN 478) warning of multiple outbreaks of NTM infections in children following pulpotomies performed in clinics where dental treatment water contained dangerously high levels of bacteria. In one Georgia outbreak (2015), waterline microbial counts were approximately 182 times the acceptable limit, and in Anaheim, CA (2016), 71 children were affected, many suffering severe complications such as permanent tooth loss, hearing loss, facial nerve palsy, and scarring.
The CDC emphasized:
“Dental providers and patients could be placed at risk of adverse health effects if dental unit water is not appropriately treated.”
“Disease-causing microorganisms found in untreated dental unit water can include Legionella, Pseudomonas aeruginosa, and nontuberculous Mycobacteria (NTM).”
“CDC recommends that all dental unit waterlines be treated regularly with disinfectants to meet the Environmental Protection Agency (EPA) regulatory standards for drinking water (≤500 CFU/mL of heterotrophic water bacteria).”
(CDC HAN 478)
Beyond the clinical consequences, the financial and reputational risks are staggering. The Anaheim outbreak alone led to 223 lawsuits against the dental practice, with litigation costs estimated in the millions of dollars. These cases involved extensive hospitalizations, surgeries, and long-term care for affected children, and the practice faced intense media scrutiny and reputational damage. (News Article)
Importantly, the risks extend not only to patients but also to dental staff, who may be exposed to aerosolized pathogens during procedures. The ADA and CDC both stress the importance of routine waterline treatment and monitoring. The ADA recommends maintaining water quality at or below 500 CFU/mL, using sterile water for surgical procedures, and following manufacturer protocols for disinfection and testing.
Failure to comply with these standards can result in regulatory violations, loss of licensure, and long-term damage to a practice’s credibility. Protecting patients and staff through proactive waterline maintenance is not just best practice—it’s essential risk management.
How Agenics Labs Helps You Stay Compliant
We recognize how much DHCP’s have on their plates, so we’ve designed our products and services to meet the unique needs of the profession, ensuring easy to obtain compliance.
1. Maintain Water Quality Standards:
Results are reported according to the 500 CFU/mL threshold
Each report includes both quantitative results and a Pass/Fail status
2. Conduct Routine Water Testing:
Annual Kits bundle four quarters of testing for convenience and savings
Automated email reminders when it is time to test
Sample vials feature volume markings to simplify pooled testing
3. Perform Event Triggered Testing:
MyCheck is compact, affordable, and ideal to keep on-hand for unplanned test events
4. Take Remedial Action for Failures:
Only Agenics Labs includes extra water quality indicators like TDS and pH to pinpoint failure causes
Expert support with every failure to help you interpret results and plan remediation actions
In-depth chemistry analysis enables science-backed protocol recommendations
5. Maintain Records for Five Years:
All mail-in tests include free access to our secure online portal, where results are stored indefinitely
MyCheck boxes come with a printed, easy to use test log sheet
Test Options for Every Practice
MAIL-IN R2A WATER TEST
The Gold Standard Test
Results in 5 days
The only test in the industry to provide photo documentation
Machine plate reading eliminates human error
EPA standard method 9215C (R2A)
MAIL-IN FLOW CYTOMETRY TEST
Express 24-Hour Test
Results in 1 day
Advanced flow cytometry technology ensures nothing is missed
No upper reporting limit
Easy, In-Office Test Paddle
Results in 2 days (dependent on incubation temperature)
Cultures and displays actual viable colonies
Protect Your Patients and Your Practice
Compliance with WAC rule 246-817-660 isn’t just about meeting regulations; it’s about safeguarding your patients and maintaining your reputation. Agenics Labs is here to support you every step of the way with reliable testing solutions and exceptional service.
To see water quality rules in your state, see our reference page
Need Help?
Let’s work together to ensure your practice stays safe, compliant, and thriving!
Click the button below to start the conversation.
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WAC 246-817-660: https://app.leg.wa.gov/wac/default.aspx?cite=246-817-660
WAC 246-817-615: https://app.leg.wa.gov/wac/default.aspx?cite=246-817-615
ADA Dental Unit Waterlines: https://www.ada.org/resources/ada-library/oral-health-topics/dental-unit-waterlines
CDC Best Practices for Dental Unit Water Quality: https://www.cdc.gov/dental-infection-control/hcp/dental-ipc-faqs/best-practices-dental-unit-water-quality.html