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5/31/2018 » 6/3/2018
2018 OSAP Annual Conference

FAQ - Dental Unit Waterlines - 2013
 FAQ -  Dental Unit Waterlines -  2013



It's my understanding that drinking water delivered to DUWL needs to be below 500 CFU's.  The Product A kits that are sold in the store say that they meet EPA requirements.  However when I call them, they tell me that they are not EPA approved.  Does the testing need to take place using a kit/testing method that is EPA approved?  Thank you in advance for your help with this. 

Ask OSAP does not review, evaluate, certify, recommend or endorse products. It is recommended that only products with the intended use of dental unit water quality testing be used. If you have further questions about procedures, specific products and their compatibility regarding your dental unit, it is recommended that you contact the manufacturer of your dental unit.

The 2003 CDC guidelines for infection control in dentistry states as follows:

Thus in 1995, ADA addressed the dental water concern by asking manufacturers to provide equipment with the ability to deliver treatment water with <200 CFU/mL of unfiltered output from waterlines (339). This threshold was based on the quality assurance standard established for dialysate fluid, to ensure that fluid delivery systems in hemodialysis units have not been colonized by indigenous waterborne organisms (340). Standards also exist for safe drinking water quality as established by EPA, the American Public Health Association (APHA), and the American Water Works Association (AWWA); they have set limits for heterotrophic bacteria of <500 CFU/mL of drinking water (341,342). Thus, the number of bacteria in water used as a coolant/irrigant for nonsurgical dental procedures should be as low as reasonably achievable and, at a minimum, <500 CFU/mL, the regulatory standard for safe drinking water established by EPA and APHA/ AWWA.1


Compliance of water in routine dental procedures with current drinking U.S. Environmental Protection Agency water standards (fewer than 500 CFU of heterotrophic water bacteria).1


Monitor dental water quality as recommended by the equipment manufacturer, using commercial self-contained test kits, or commercial water-testing laboratories.1


VIII. Dental Unit Waterlines, Biofilm, and Water Quality

A. General Recommendations

1. Use water that meets EPA regulatory standards for drinking water (i.e., <500 CFU/mL of heterotrophic water bacteria) for routine dental treatment output water (IB, IC) (341,342).

2. Consult with the dental unit manufacturer for appropriate methods and equipment to maintain the recommended quality of dental water (II) (339).

3. Follow recommendations for monitoring water quality provided by the manufacturer of the unit or waterline treatment product (II).

4. Discharge water and air for a minimum of 20– 30 seconds after each patient, from any device connected to the dental water system that enters the patient’s mouth (e.g., handpieces, ultrasonic scalers, and air/water syringes) (II) (2,311,344).

5. Consult with the dental unit manufacturer on the need for periodic maintenance of antiretraction mechanisms (IB) (2,311).1

The US Environmental Protection Agency (EPA) sets regulatory standards for drinking water.

The American Dental Association’s (ADA’s) Statement on Dental Unit Waterlines states as follows:

Water Quality Monitoring: It is important that waterline treatment schedules include water quality monitoring. Simple and inexpensive methods to estimate the number of free-floating heterotrophic bacteria in dental unit water are available. A well-designed water quality indicator should be self-contained and easy to use in-office; accurately detect a wide concentration range and type of aerobic mesophilic heterotrophic waterborne bacteria within a reasonable incubation time at room temperature; and be relatively inexpensive to use. In addition to in-office testing kits, laboratories across the U.S. also offer mail-in testing services.2

The ADA also states the following regarding dental unit water quality:


The only way to know that a dental unit waterline cleaning regimen is effective is to test the water coming out of the unit. Dental unit water testing products and services are used to monitor the dental unit water quality. Testing is usually done using three samples of water taken from the same dental unit. Dental equipment (e.g. handpieces) should be removed before the samples are taken. It is important that you do not contaminate the water during sampling; therefore, wear gloves and follow the directions for the particular product or service carefully.3

Suggested further reading includes:

Statement on Dental Unit Waterlines  2

Dental unit waterlines -- infection control includes safe dental unit water 4

In summary, the EPA sets drinking water standards. Only products with the intended use of dental unit water quality testing should be used. Your dental unit manufacturer should be contacted for further information on methods and equipment for monitoring dental unit water quality.


1)     Kohn WG, Collins AS, Cleveland JL, Harte JA, Eklund KJ, Malvitz DM, Centers for Disease Control and Prevention (CDC). Guidelines for infection control in dental health-care settings—2003. MMWR Recomm Rep 2003;52(RR-17):1-61.   Accessed on March 23, 2013.

2)     American Dental Association. Statement on Dental Unit Waterlines.    Accessed on March 23, 2013.

3)     American Dental Association. Dental Unit Water Quality.  Accessed on March 23, 2013.

4)     Dentistry IQ. Dental unit waterlines -- infection control includes safe dental unit water  Accessed on March 23, 2013. 





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