September is Dental Infection Control Awareness Month (DICAM), and the Association for Dental Safety (ADS) is excited to highlight key topics that keep dental visits safe for everyone. For the second week, we’re focusing on a critical but sometimes overlooked area: Dental Unit Waterlines (DUWLs).

Why Are Dental Unit Waterlines Important?

Dental unit waterlines are the narrow tubes that deliver water to your handpieces, air/water syringes, and ultrasonic scalers. These lines can harbor a slimy layer of bacteria called biofilm. Biofilm forms due to the tubing’s design, low flow rates, and periods of stagnation. If not properly maintained, DUWLs can become a source of harmful microorganisms like Legionella, Pseudomonas aeruginosa, and nontuberculous Mycobacteria. Outbreaks linked to contaminated dental water have caused serious infections, especially in children, underscoring the importance of rigorous infection prevention practices. [1]

Dental Unit Waterlines Best Practices

• Treat waterlines regularly with disinfectants to meet the Environmental Protection Agency (EPA) standard of ≤500 colony forming units (CFU)/mL of heterotrophic water bacteria.
• Monitor water quality routinely as recommended by the dental unit or waterline treatment product manufacturer. This ensures that treatments are effective and water remains safe.
• Flush water and air lines for 20 - 30 seconds after each patient to help reduce microbial contamination.
• Use sterile water or saline for all oral surgical procedures, delivered via sterile devices that bypass the dental unit waterlines.
• Document all maintenance, monitoring, and staff training related to DUWLs as part of your infection prevention program. [2]

Common Dental Unit Waterline Questions

Q: How often should I test dental unit waterlines?
A: Water quality should be monitored routinely, following the recommendations of the equipment or treatment product manufacturer. Regular testing helps ensure that disinfection protocols are working and provides documentation of compliance.

Q: What should I do if testing results exceed the CDC recommended limit of ≤500 colony forming units [CFU]/mL of heterotrophic water bacteria?
A: The unit should be treated according to manufacturer IFU, and re-tested immediately after treatment. If a unit remains resistant to treatment over time, it may be necessary to replace waterlines or other water-bearing components. [1]

Q: What should I do to maintain dental unit water quality?
A: There are many commercial products and devices available to disinfect and maintain dental unit waterlines, including:

• Self-contained water systems (e.g., independent water reservoir) combined with chemical treatment (e.g., periodic or continuous chemical germicide treatment protocols).
• Systems designed for single-chair or entire-practice waterlines that condition or treat incoming water to remove or inactivate microorganisms.
• Combinations of these methods.

Available products to treat waterlines include tablet systems, continuous release straws and cartridges, initial and periodic shock treatments, and centralized systems. All products and systems must be used and maintained according to the manufacturer instructions for use (IFUs). If you have questions about the IFUs, contact the manufacturer of the treatment product or device that you are using. [1]

Q: How can I tell if waterlines are contaminated?
A: Signs of biofilm or contamination include musty odors, cloudiness, particulates in the water, or clogging of lines. If you notice any of these signs, lines should be inspected and replaced if necessary.

Q: If I flush the waterlines, will that get rid of the biofilm?
A: Flushing helps reduce planktonic (free-floating) bacteria and clears out patient material, but it doesn’t remove biofilm from the tubing. Chemical treatment is required to inactivate and remove biofilm. [3]

Q: What should be used for irrigation during oral surgery?
A: Only sterile saline or sterile water should be used, delivered with sterile, single-use or sterilizable devices that bypass the dental unit waterlines.

Recommended Dental Unit Waterline Resources:

• ADS Dental Unit Waterline Toolkit
• Ask ADS
• Best Practices for Dental Unit Water Quality
• Basic Expectations for Self Care Modules: Dental Unit Water Quality
• CE Center - Dental Unit Waterline Courses
• Dental Unit Water Quality: Organization for Safety, Asepsis and Prevention White Paper and Recommendations - 2018
• DICAM Infection Prevention and Safety Resource Toolkit
• Infection Control and Management of Hazardous Materials for the Dental Team, 7th Edition, Chapter 15
• Infection Control in Practice (ICIP), Volume 22, Issue 4
• Infection Control in Practice (ICIP), Volume 24, Issue 2

Get Involved!

DICAM is the perfect time to review protocols, educate your team, and share your commitment to patient safety. For more information, resources, and ways to participate, click here.

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