Dental Unit Water Lines

Guidelines for Practice Success | Managing Regulatory | Centers for Disease Control and Prevention

All dental practices should properly and regularly maintain dental unit water lines as part of their regular infection control protocols. While infections caused by contaminated water lines are rare, especially among healthy individuals, other people, such as the elderly and patients with compromised immune systems, may be more susceptible to infection.

Dental unit water lines can harbor numerous microorganisms that can multiply inside the tubing and result in biofilms that can harbor bacteria, fungi, algae and protozoa. Once formed, biofilms can increase the numbers of free-floating microorganisms in water that exits the water lines. Proper and regular maintenance of dental unit water lines will help ensure that the water that runs through the lines meets the safe drinking water standard.

CDC’s Summary of Infection Prevention Practices in Dental Settings advises that:

“All dental units should use systems that treat water to meet drinking water standards (i.e., ≤ 500 CFU/ mL of heterotrophic water bacteria). Independent reservoirs—or water-bottle systems—alone are not sufficient. Commercial products and devices are available that can improve the quality of water used in dental treatment. Consult with the dental unit manufacturer for appropriate water maintenance methods and recommendations for monitoring dental water quality.”

Based on the agency’s guidance, combination approaches are an effective way to adequately control dental unit water quality. It’s important to recognize that an independent water reservoir/bottle alone is not enough. The biofilm in the dental unit water line must be controlled by additional technologies registered by the Environmental Protection Agency (EPA) or cleared by the Food and Drug Administration (FDA) for dental unit water quality management. Examples include:

  • chemical treatment regimens
  • source water treatment systems
  • point-of-use filters

When performing surgical procedures, use only sterile solutions as a coolant/irrigant using an appropriate delivery device, such as a sterile bulb syringe, sterile tubing that bypasses dental unit waterlines, or sterile single-use devices. Guidance on dental unit water quality can be found in the CDC’s Guidelines for Infection Control in Dental Health-Care Settings—2003 and the CDC’s questions and answers on Dental Unit Water Quality. While the suggestions above are options, all practices should strictly adhere to appropriate maintenance protocols and check with the manufacturer of their dental units before implementing any procedures or processes to ensure compliance with the agency’s recommendations. If you are using a waterline disinfectant or system, verify your processes with the manufacturer.

Refer to ADA Do’s and Don’ts for Maintaining Dental Unit Water Lines for more information and helpful tips. Links to additional information available through the American Dental Association (ADA) are included in the list of Resources below.