Short AnswerIt depends on the location and patient population. Faucet aerators can harbor biofilms containing a variety of waterborne microorganisms, including Legionella and opportunistic gram-negative bacteria.CDC recommends monthly cleaning and disinfection of faucet aerators and showerheads under specific high-risk circumstances as part of Legionella prevention. However, this is not a universal requirement for all healthcare faucets.For other locations, cleaning, disinfection, removal, or replacement should be guided by the facility's Water Management Program and Water Infection Control Risk Assessment (WICRA), taking into consideration patient populations, fixture locations, and potential exposure risks.No Medical JargonBacteria naturally attach to wet surfaces inside plumbing systems, forming communities called biofilms. These can develop in any faucet, whether or not it has an aerator.Aerators contain screens and small internal passages where sediment and biofilm can accumulate. These structures provide additional surfaces for microorganisms to attach and may be difficult to clean thoroughly.Aerators also mix air into the water stream. Depending on the fixture design and water flow, contaminated water can disperse microorganisms through droplets or aerosols.Finding bacteria on an aerator isn't necessarily surprising, and a positive culture doesn't automatically mean the faucet is unsafe.Why It MattersWaterborne microorganisms can cause serious healthcare-associated infections, particularly among immunocompromised and critically ill patients.Organisms associated with healthcare water systems include:Legionella speciesPseudomonas aeruginosaAcinetobacter speciesStenotrophomonas maltophiliaNontuberculous mycobacteria Patients may be exposed through contaminated water, droplets, aerosols, or contact with contaminated surfaces and medical equipment.Although CDC's specific monthly aerator maintenance recommendation addresses Legionella prevention, other waterborne pathogens are also important considerations when evaluating faucet design, maintenance, and patient exposure risks.Importantly, removing an aerator does not eliminate biofilms within the faucet or plumbing system, nor does it guarantee that water will not splash.Best Practice1. Assess the RiskUse your facility's WICRA to evaluate:Patient populations and susceptibility to infectionFaucet locations and intended usesPotential exposure to contaminated water, droplets, or aerosolsPlumbing design and maintenance historyExisting water management controlsPrevious water-related infections or identified hazards CDC provides a free, fillable Water Infection Control Risk Assessment (WICRA).2. Establish a Risk-Based Maintenance ScheduleUnder Section D.VI.B.4 of CDC's Guidelines for Environmental Infection Control in Health-Care Facilities, CDC recommends monthly removal, cleaning, and disinfection of showerheads and faucet aerators in areas with patients at risk for legionellosis when Legionella is not detectable in unit water.For this specific recommendation, CDC identifies a chlorine-based, EPA-registered disinfectant or, if an appropriate registered product is unavailable, a 500–615 ppm sodium hypochlorite solution (approximately a 1:100 dilution).This is a Category II recommendation for particular high-risk circumstances, not a universal monthly maintenance requirement for every faucet.For other locations, establish maintenance intervals based on the facility's risk assessment.CDC does not provide a complete step-by-step procedure for aerator cleaning and disinfection. Facilities should establish procedures that address:Removal and inspectionCleaning of sediment and mineral depositsDisinfectant selection and contact timeMaterial compatibilityRinsing and safe reinstallationReplacement when cleaning is ineffective or components are damagedDocumentation of maintenance activities Follow applicable product labeling, manufacturer instructions, and facility water management procedures.3. Evaluate Splash ZonesFaucet maintenance is only one component of water-related infection prevention.Consider whether:Water flows directly onto the drain, increasing splashing.Water pressure contributes to droplet dispersal.Clean supplies, medications, or patient-care equipment are stored within the sink's splash zone.Splash guards are needed to protect nearby clean areas.Sink basins, drains, faucets, and surrounding surfaces are included in appropriate cleaning procedures. CDC's water management guidance addresses separating sinks from medication preparation and clean supply storage areas, including maintaining more than 3 feet of separation when splash guards are absent.4. Environmental Cultures: Know When and Where to TestCDC generally discourages routine, random environmental microbiologic sampling because:Microorganisms are commonly present in plumbing systems.Positive cultures do not necessarily indicate a patient safety risk.Established thresholds for interpreting many environmental culture results are lacking.Sampling methods and environmental conditions can influence results.Testing without a defined objective may lead to unnecessary interventions. Targeted environmental sampling may be appropriate during outbreak investigations, evaluations of potentially hazardous conditions, or as part of a defined water management strategy.Environmental specimens should not automatically be submitted to the hospital's routine clinical microbiology laboratory. Clinical laboratories primarily process patient specimens, and their routine culture methods may not be appropriate for environmental testing.When environmental sampling is indicated, Infection Prevention should collaborate with the laboratory and Water Management Team to determine whether the facility has the appropriate testing capabilities or whether a laboratory specializing in environmental microbiology should be used.Before collecting samples, establish:Why testing is necessary.Who will collect the samples and how.Which laboratory will perform the testing.What methods and quality assurance procedures will be used.How the results will be interpreted.What corrective actions will follow. CDC specifically recommends that water samples be analyzed by laboratories using established methods and quality assurance protocols.5. Define ResponsibilitiesWork with Facilities, Environmental Services (EVS), Infection Prevention, and the Water Management Team to establish a documented maintenance process.The policy should identify:Which locations require routine maintenanceInspection, cleaning, and replacement schedulesApproved cleaning and disinfection methodsResponsibilities for completing and documenting maintenanceProcesses for reporting concerns and initiating corrective actions The goal is a consistent, risk-based approach rather than reacting to bacterial growth alone.IP PearlBiofilm formation is expected. Patient exposure is what we're trying to prevent.A positive aerator culture does not automatically indicate an infection prevention failure.Although CDC's monthly cleaning recommendation specifically addresses Legionella prevention in certain high-risk settings, faucet aerators can also harbor other opportunistic waterborne pathogens.Focus on identifying high-risk locations, minimizing water-related exposures, maintaining plumbing fixtures appropriately, and preventing contamination of surrounding surfaces.And remember: The sink's splash zone may be just as important as the aerator itself.ReferencesCDC — Guidelines for Environmental Infection Control in Health-Care Facilities: Water Recommendations. See Section D.VI.B.4 for the high-risk monthly aerator maintenance recommendation.CDC — Water in Healthcare Facilities. Includes discussion of waterborne pathogens, faucet aerators, and Table 17.CDC — Water Infection Control Risk Assessment (WICRA). Fillable assessment tool.CDC — Considerations for Reducing Risk: Water in Healthcare Facilities. Water management, sinks, drains, and splash prevention.CDC — Environmental Sampling: General Principles. Guidance on environmental sampling and interpretation.ASHRAE — Guidance for Water System Risk Management. Information on ANSI/ASHRAE Standard 188 and ASHRAE Guideline 12.