Legionella pneumophila
Legionella pneumophila is a bacterium that can cause a severe form of pneumonia known as Legionnaires' disease. It is a gram-negative bacterium that thrives in warm water environments and can be found in natural water bodies as well as man-made water systems.
EPA MCLG
0 mg/L
EPA's health goal is zero — no known safe level of exposure. This is a goal, not an enforceable limit.
Health Effects
Exposure to Legionella pneumophila can lead to Legionnaires' disease, which is characterized by symptoms such as cough, shortness of breath, high fever, muscle pains, and headaches. In severe cases, it can lead to respiratory failure and death, particularly in individuals with weakened immune systems.
Affected Organs & Systems:
Source: EPA — Legionella (Drinking Water) (retrieved 2026-07-27)
Common Sources
- Water systems (e.g., cooling towers, hot tubs, plumbing systems)
- Soil and natural water sources
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About the EPA MCLG
The EPA MCLG is the level of a contaminant in drinking water below which there is no known or expected risk to health. It is a non-enforceable public health goal, and is often stricter than the legal limit (MCL) water systems must meet.
Contaminant Type
Legionella pneumophila is classified as a Bacteria contaminant.
This contaminant primarily affects the Lungs, Respiratory system, and other systems.
Related Bacteria Contaminants
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