Background: An outbreak of surgical site infection (SSI) due to environmental mycobacteria (EMB) occurred in a hospital in Eastern India. Method: A quality improvement project (QIP) was undertaken to analyze the causes and prevent further outbreak. Step (1) Proof of the need: Four patients who had undergone pacemaker implantation consecutively during a 10-day period developed SSI. Step (2) Diagnostic journey: Since all patients developed SSI within 2 months of implantation, a common source of infection was likely. Atypical mycobacteria (AMB) were grown from surgical sites as well as from the surface of operation table, image intensifier, and lead aprons. It was a rapid growing variety that lacked pigment, a characteristic of EMB with pathogenic potential. The EMB was finally traced to its source, the overhead water tank. Step (3) Remedial journey: By thorough cleaning of the water tank and enriching its chlorine content, the EMB was eliminated from its source. Step (4) Holding the gains: Protocol for cleaning the water tank once in 3 months was made. A checklist was prepared to ensure compliance to asepsis protocol in the operation theater. In the ensuing 5 years, the infection did not recur. Result: The bacteria that caused SSI were identified as EMB that grew in the water tank and contaminated the operation room. It could be eliminated by appropriate measures. Interpretation: Water is a potential reservoir for EMB. Use of the term ‘environmental mycobacteria’ instead of ‘atypical mycobacteria’ will generate awareness about contamination as the cause of SSI.