Effects of Hard Water Scale in Plumbing Systems — Vastly Increased Biofilm and Legionella Growth

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Tel: +1 888-416-8626
Email: info@legionellacontrolsystems.com

There is a lot of life living in our piping systems. When pipe walls are smooth, they don’t pose large risk in growing Legionella colonies. When Legionella and other bacteria can find a home in scaled plumbing, they begin to create a biofilm. This is where problems begin to magnify. A biofilm is a collection of cells that have adhered to a pipe (usually a rough surface) and began to multiply. Hard water scaling is a major attributing factor for Legionella growth because it provides a place for biofilm to grow, which is a breeding ground for Legionella. It also protects it from disinfectants such as chlorine and monochloramines. Bacteria can become dangerous as they begin to colonize and multiply. Industrial Legionella Control Water Softeners work to prevent this from happening.

pipe with biofilm and Legionella colonies
An example of pipe with biofilm and Legionella colonies

If water is not properly softened, hard water scaling begins to occur. This is where calcium and magnesium begin to adhere to the pipe walls. Scaling does not happen uniformly. It creates large cracks and crevices on the interior walls of piping. New piping and piping with consistently softened water are smooth. Without scale, the smooth pipe walls make it difficult for bacteria to adhere to and begin to form biofilm and multiply. Over time, however, without proper softening, scale forms and it creates a rich environment for Legionella growth and it begins to multiply.

Pipe with hard water scaling and new pipe
Left: Pipe with hard water scaling. Right: New pipe

In the examples above, the pipe on the left has a large amount of hard water scale buildup, which is not uncommon for older buildings. This rough surface provides a perfect breeding ground for Legionella and other harmful pathogens. Some studies have shown that scale can increase Legionella growth by over 600%!

Industrial water softeners are often overlooked as a key element to water safety in a facility. Doing what you can to ensure clean, smooth pipes is a great first step in the fight against Legionella and other harmful pathogens.

Sediment can be another important factor that contributes to the risk of Legionella. Learn about sediment and Legionella. plus water age and its effect on Legionella.

Industrial water softeners paired with testing water quality are key components in any good Legionella water management plan.

Legionella Control Systems and Water Management Plans

Want to keep your customers, patients and employees safe? Contact Legionella Control Systems at info@legionellacontrolsystems.com or 888-416-8626 for Legionella control systems, including water softeners. design, service and sales of industrial water systems in Indiana, the Midwest and throughout the U.S. Our experienced engineers are ready to help.


See all of the Legionella risk factors: Water Age (stagnant water), Temperature, Disinfectant Levels, and Scale/Sediment.

Contact Legionella Control Systems for CDC Legionella risk assessment and Legionella testing.