Written By: Canadian Water Compliance | On
Most people assume that water flowing through pipes is clean and safe, but hidden within plumbing systems, biofilm can pose serious risks to water quality and public health. Biofilm is a sticky layer of bacteria, fungi, and other microorganisms that can form inside pipes, fixtures, and water storage tanks. This environment provides the perfect breeding ground for harmful pathogens, including Legionella, Pseudomonas, and Mycobacterium, which can lead to waterborne illnesses.
In this guide, we’ll cover:
✅ What biofilm is and how it forms
✅ Common waterborne pathogens found in biofilm
✅ The risks associated with biofilm contamination
✅ How to prevent and remove biofilm in plumbing systems
✅ Ontario regulations on water safety and biofilm management
Biofilm is a complex, slimy structure composed of microorganisms that attach themselves to surfaces exposed to water. Once bacteria adhere to a surface, they secrete a sticky substance that allows them to multiply and form protective layers, making them resistant to disinfection.
Several factors contribute to the formation of biofilm in plumbing systems:
🔹 Stagnant Water: Low water flow allows bacteria to settle and colonize.
🔹 Warm Temperatures: Biofilm thrives in temperatures between 25–45°C (77–113°F), making hot water systems particularly vulnerable.
🔹 Pipe Material: Certain materials, like PVC and iron pipes, encourage bacterial adhesion.
🔹 Corrosion and Scaling: Rough surfaces provide ideal conditions for bacteria to cling to.
🔹 Nutrient Availability: Biofilm thrives in the presence of organic matter, sediment, and trace nutrients.
Biofilms protect bacteria from chlorine and other disinfectants, making them particularly dangerous in drinking water systems. Some of the most common and harmful pathogens found in biofilm include:
🔹 Disease: Legionnaires’ disease & Pontiac fever
🔹 Source: Cooling towers, hot water tanks, and large plumbing systems
🔹 Risk: Inhalation of aerosolized contaminated water
🔹 Disease: Skin infections, pneumonia, and bloodstream infections
🔹 Source: Faucets, showerheads, and medical equipment
🔹 Risk: Particularly dangerous for immunocompromised individuals
🔹 Disease: Respiratory infections and lung disease
🔹 Source: Biofilm in hospital water systems and household plumbing
🔹 Risk: Can be inhaled or ingested, affecting people with weak immune systems
🔹 Disease: Gastrointestinal illnesses, diarrhea, and kidney failure
🔹 Source: Contaminated groundwater entering plumbing systems
🔹 Risk: Ingestion through drinking water
If left unchecked, biofilm buildup can lead to serious health risks, especially in hospitals, hotels, and long-term care facilities, where vulnerable populations are at higher risk.
⚠️ Increased Risk of Waterborne Disease Outbreaks – Pathogens can detach from biofilm and enter the water supply.
⚠️ Resistance to Disinfection – Chlorine and standard cleaning methods may not be enough to remove biofilm.
⚠️ Reduced Water Quality – Biofilm can cause bad taste, odors, and discoloration in drinking water.
⚠️ Legionella Contamination in HVAC Systems – Cooling towers and hot water systems with biofilm can lead to Legionnaires' disease outbreaks.
💧 1. Regular Water Testing
Routine Legionella and bacterial testing should be performed in high-risk facilities, including:
✅ Hospitals & Healthcare Facilities – Testing for biofilm-forming pathogens is crucial for patient safety.
✅ Hotels & Residential Buildings – Regular flushing of plumbing systems prevents biofilm buildup.
✅ Cooling Towers & Industrial Water Systems – Monthly Legionella testing is required in Ontario.
💧 2. Flushing and Disinfection Protocols
✅ Increase water circulation – Avoid stagnant water conditions in pipes.
✅ Thermal Disinfection – Flushing hot water through pipes at 60°C (140°F) for at least 30 minutes can reduce biofilm.
✅ Chemical Disinfection – Use of chlorine dioxide, monochloramine, or peracetic acid to remove biofilm-forming bacteria.
💧 3. Filtration and Pipe Maintenance
✅ Install point-of-entry or point-of-use filters to remove bacteria.
✅ Regularly clean and replace water filters to prevent biofilm accumulation.
✅ Monitor pipe corrosion and replace aging pipes to reduce bacterial adhesion.
In Ontario, biofilm control and water safety are covered under various public health and environmental regulations:
📜 Ontario Public Health Standards – Requires regular water testing in healthcare facilities, long-term care homes, and public buildings.
📜 Ontario Regulation 243/07 (Schools & Daycares) – Mandates lead and bacterial testing in plumbing systems for children’s facilities.
📜 Ontario Regulation 170/03 (Safe Drinking Water Act) – Covers microbial water quality standards for municipal water systems and large buildings.
📜 ASHRAE Standard 188 – Provides risk management guidelines for Legionella control in building water systems, often referenced in industry compliance.
Biofilm in plumbing systems is a major but often overlooked threat to water safety. From Legionella outbreaks in cooling towers to Pseudomonas contamination in hospital water, biofilm enables the spread of dangerous waterborne pathogens.
✅ Regular water testing, proper maintenance, and following Ontario’s regulations can help prevent biofilm formation and protect public health.
🔎 Need expert water testing services? Canadian Water Compliance provides biofilm testing, Legionella risk assessments, and water treatment solutions for businesses across Ontario.
📞 Contact us today to ensure your water is safe and compliant!
