Legionella is a bacterium that can cause a potentially fatal disease, Legionnaires’ disease (legionellosis). Legionella are commonly found in warm water containing mechanical equipment such as cooling towers, evaporative condensers, air washers, humidifiers, misters, hot water heaters, spas, fountains, car wash facilities and plumbing fixtures. Legionella infect people when they inhale legionella-containing aerosols from these sources. Through legionella water testing labs, companies and corporations are able to accurately and routinely check for these bacteria in order to prevent this disease.
Aside from endangered human health, the owner or manager of a building or warm water containing equipment where legionella had been found can be faced with liability claims. Developing a legionella water testing plan will provide an early warning if a problem exists with the effectiveness of current legionella control methods.
Carrying out routine legionella water testing also enhances the safety of facility staff and occupants. The American Industrial Hygiene Association (AIHA) May 2015 publication “Recognition, Evaluation, and Control of Legionella in Building Water Systems” LEGG15-781, provides guidance on recognition, evaluation, and control of Legionella colonization and amplification in common building water systems, both with and without any associated disease (legionellosis). An author of this publication has stated that the 2015 ASHRAE Standard 188 "is all but silent on how to validate the effectiveness of control measures used to prevent legionella amplification"..."which is akin to measuring temperature and ventilation rates at a refinery to gauge the effectiveness of controlling benzene exposure rather than sampling for benzene itself and determining the actual exposure level."
When risk management procedures for control of legionella in building water systems need validation, legionella water testing is used. GTS does not recommend the culture method for testing environmental water samples because legionella colonies on agar media are often overgrown or inhibited by competing microbial flora that mask the presence of legionella colonies, particularly with water samples taken from warm water-containing mechanical equipment exposed to the environment such as fountains, cooling towers and saunas. If you’re in need of testing your water systems for legionella, contact GTS Water Testing Lab at (410) 961-6638 or visit www.legionella.com.