In 2007, a water engineering firm contacted Blue Earth Labs to assist a research hospital with a major Legionella contamination problem within their drinking water system. The goal of the study was to determine whether Clearitas could minimize the Legionella problem while having little or no adverse effects on the facility’s infrastructure and water quality.

Distal points within the hospital distribution system were measured weekly for four weeks prior to the trial of Clearitas. The following metrics were measured at each point: bacterial, pH, copper levels, lead levels, Langelier and Ryznar Indices and disinfection by-products.


Clearitas was dosed at a rate of 1 gallon of Clearitas to 2,000 gallons of incoming water supply to the hospital. Both the hot and cold water distribution systems were measured during the course of the study.

Prior to the addition of Clearitas, the hospital had regular and lasting Legionella issues. Two weeks after introducing Clearitas into the hospital’s water system, Legionella counts went down and stayed very low throughout the study and chlorine residuals went up.


Overall, the addition of Clearitas to this hospital’s water supply had a rapid, impactful effect on the Legionella problem within the water distribution system. After two weeks, the Legionella counts went down to near undetectable levels and the chlorine residual within the hospital went up significantly. Moreover, the other water chemistries seem to be unchanged by the addition of Clearitas during this study. Little or no change occurred for pH, metal levels, corrosion, etc. Where changes were observed in this data, the numbers are relatively small and well below EPA guidelines. Thus, hospitals and healthcare facilities can use Clearitas for both Legionella prevention and Legionella remediation.

For specific values and measurements of the above mentioned metrics, please view the full case study.