During renovations, what is the risk associated with lack of water flow due to capped plumbing?

• A. It can lead to stagnation and possible spread of microorganisms
• B. It improves water quality
• C. It reduces risk of contamination
• D. It has no impact on infection risk

Answer: (A)

Water stagnation in unused or capped plumbing during renovations creates conditions that favor microbial growth. When water isn’t moving, disinfectant residuals fade, biofilms form, and nutrients can accumulate, allowing bacteria such as Legionella and Pseudomonas to multiply. When the system is later flushed or used, these organisms can be released into the water and potentially become aerosolized, increasing infection risk for occupants. That’s why stagnation is a real infection risk, not an improvement or have no impact.