Two-Year Evaluation of in an Aging Residential Building: Assessment of Multiple Potable Water Remediation Approaches.

is an opportunistic waterborne pathogen that is difficult to eradicate in colonized drinking water pipes. control is further challenged by aging water infrastructure and lack of evidence-based guidance for building treatment. This study assessed multiple premise water remediation approaches designed to reduce within a residential building located in an aging, urban drinking water system over a two-year period. Samples (n=745) were collected from hot and cold-water lines and quantified via most probable number culture. Building-level treatment approaches included three single heat shocks (HS), three single chemical shocks (CS), and continuous low-level chemical disinfection (CCD) in the potable water system. The building was highly colonized with with 71% positivity. Single HS had a statistically significant reduction one day post treatment but no significant reduction one, two, and four weeks post treatment. The first two CS resulted in statistically significant reduction at two days and four weeks post treatment, but there was a significant increase at four weeks following the third CS. CCD resulted in statistically significant reduction ten weeks post treatment implementation. This demonstrates that in a building highly colonized with , sustained remediation is best achieved using CCD.