A new review looks at the infection risks associated with organisms like Legionella pneumophila, Mycobacterium avium, and Pseudomonas aeruginosa which can persist and grow in household plumbing.
Water travels through the public drinking water system to the home, where it is distributed though the pipes, water taps, shower heads, and the hot water heater. Harmless microbes that present no health risks grow freely in household plumbing, but under the right conditions, potentially harmful pathogens such as Legionella and Pseudomonas aeruginosa can also grow and flourish. These microbes are referred to as “opportunistic pathogens”, which present little or no risk until they multiply in large numbers in places where stagnant water accumulates, like shower heads and the sediment in hot water heaters. They can then cause infection if they are ingested, or inhaled as droplets from the shower head. Those with compromised immune systems are at higher risk from these opportunistic pathogens.
The review concludes that the frequency of these infections is rising and will likely continue to rise as the number of at-risk individuals is increasing. However, it is possible to take measures (e.g., raise hot water heater temperatures and filter water) to reduce home exposures. Flushing the toilet in the early morning is advisable – one toilet flush can take care of a good deal of that older water sitting around overnight in the plumbing system. Allowing the shower to run for a few minutes before taking a shower will clear any organisms which have grown in the stagnant water of the shower head since the previous use.
The review can be found at Environ Health Perspect 123:749–758; http://dx.doi.org/10.1289/ehp.1408692.
Also find more at: http://www.waterandhealth.org/potentially-harmful-pathogens-home/