The Environmental Protection Agency (EPA), the American Public Health Association (APHA), and the American Water Works Association (AWWA) have set a limit of 500 CFU/mL for aerobic, heterotrophic, mesophilic bacteria in drinking water.1,2 Treated municipal water enters a healthcare facility via the water main and is distributed throughout the facility by a network of pipes. To minimize potential stagnation, pipe-runs should be as short as practical and insulated.1 Water stagnation facilitates waterborne pathogen multiplication and aerosolization promotes pathogen dispersal. Measures to prevent the spread of waterborne pathogens include hand hygiene, glove use, barrier precautions, and eliminating/minimizing contamination at point-of-use fixtures.1,2 Infection prevention strategies related to hand hygiene and the use of personal protective equipment are presented elsewhere.4,5
Universal point-of-use fixtures for water in healthcare facilities include sinks, faucets, toilets, and eye-wash stations.1,2 The potential for these fixtures to serve as a reservoir for pathogenic organisms has long been recognized. Sinks, faucets, and toilets should be cleaned and disinfect on a regular basis using an EPA-registered product (see section on Fomite-related Infection Prevention and Control). Eyewash stations should be flushed weekly with sterile water.
Special point-of-use fixtures include high-speed handpieces, sonic and ultrasonic scalers, and air-water syringes. These devices are connected to a water source by dental unit waterlines (DUWLs), which consist of small-bore plastic tubing. The presence of biofilms of waterborne bacteria (e.g., Legionella spp., Pseudomonas aeruginosa, and NTM) in DUWLs has been confirmed.1,2 Strategies to maintain acceptable water quality in oral healthcare settings are summarized in Table 2.1,2
Table 2. Recommendations to Maintain Acceptable Water Quality in Oral Healthcare Settings.1,2
- Dental unit water lines.
- Use water that meets nationally recognized standards for drinking water (i.e., <500 CFU/mL) for routine dental treatment.
- Take precautions to prevent waterborne contamination of DUWLs and instruments.
- Consult with dental water-line manufacturers to (1) determine suitable methods and equipment to obtain the recommended water quality; and (2) determine appropriate methods for monitoring the water to ensure quality is maintained.
- After each patient, discharge water and air for a minimum of 20-30 seconds from all devices (e.g., handpieces, ultrasonic scalers, and air-water syringe) connected to the dental water system.
- Boil-water advisory.
- Do not deliver water to the patient through dental equipment/instruments (e.g., handpieces, ultrasonic scalers, and air-water syringe) connected to the public water system.
- Do not use water from the public water system for patient rinsing or handwashing.
- Use bottled water for patient rinsing.
- If hands are not visibly soiled, use an alcohol-based hand-rub.
- If the hands are visibly soiled use bottled water and soap or antiseptic towelettes.
- When boil-water advisory is cancelled.
- Follow guidelines provided by the local water system authority regarding adequate flushing of waterlines.
- If no guidelines are provided, flush DUWLs and faucets for 1-5 minutes before using water for patient care.
- Disinfect DUWLs according to dental unit manufacturer’s recommendations.
- Water quality for oral surgical procedures.
- Use specifically designed point-of-use devices (e.g., bulb syringe, single-use disposable products, and sterilizable tubing) for the delivery of sterile irrigating fluids.
