Maintenance procedures include inspection, detection and remediation of probable sources of airborne contaminants and water.

In its publication, Indoor Air Quality, SMACNA (Sheet Metal and Air Conditioning Contractors' National Association, Inc.) makes several system design and maintenance recommendations to prevent mold growth:

• Promptly detect and permanently repair all areas where water collection or leakage has occurred.
• During the summer, cooling coils should be run at a low enough temperature to properly dehumidify conditioned air.
• Check for, correct, and prevent further accumulation of stagnant water under cooling deck coils of air handling units, through proper inclination and continuous drainage of drain pans.
• Water-damaged furnishings, including carpets, upholstery and ceiling tiles, should be discarded rather than disinfected, to effectively eliminate microbial contamination.
• Air handling units should be constructed so that equipment maintenance personnel have easy and direct access to both heat exchange components and drain pans for checking drainage and cleaning. Access panels or doors should be installed where needed.
• Materials with hard surfaces where moisture collection has promoted microbial growth (e.g., drain pans, cooling coils) should be cleaned and disinfected with detergents, chlorine- generating slimicides (bleach), and/or proprietary biocides. Care should be taken to insure that these chemical agents are removed before air handling units are reactivated.