Rain and heavy storms are known for shutting down events, flooding roads, and knocking out power. But did you know they can disrupt your building’s water safety too? From Legionella lurking in plumbing systems to spikes in E. coli after flooding, extreme weather events like hurricanes and heavy rainstorms can severely compromise water quality. And for communities where large populations depend on a shared water system, the stakes may be even higher.
How Storms Impact Building Water Systems
Tropical cyclones, heavy rainfalls, and strong winds increase the risk of bacterial contamination in water supplies by:
- Overwhelming sewage and drainage systems
- Flooding and damaging local infrastructure
- Increasing runoff from contaminated surfaces (e.g. roads, agricultural areas) into water supplies
- Disrupting normal water usage patterns, allowing stagnation and biofilm growth in pipes
Pathogenic risks after storms
Analysis of storms across the U.S. shows reveal many increased pathogen exposures following extreme weather events. These pathogens don’t peak immediately. Instead, they follow a “lag effect,” with cases rising days or weeks after the storm, catching facilities off-guard. This is because it takes time for pathogens to create infections and for health authorities to detect those infections.
1. Legionella
- Hospitalizations for Legionnaires’ disease increased by 42% two weeks after a major storm.
- In areas where more than 75% of the population was storm-exposed, cases continued rising for three weeks.
- Legionella thrives in warm, stagnant water and biofilms, which are all conditions made worse by post-storm disruptions.
2. E. coli
- Cases spiked 48% one week after storms, especially when rainfall exceeded 100 mm.
- E. coli typically enters systems through stormwater runoff or cross-contamination during infrastructure damage.
3. Cryptosporidium
- Storm weeks saw a 52% increase in cases.
- This chlorine-resistant protozoan is at elevated levels during storms due to runoff from agricultural areas or septic systems. It is especially dangerous because it survives in municipal supplies unless filtered or inactivated by UV.
Proactive Steps Building Owners Can Take
- Install a point-of-entry disinfection system, such as UV, to create a biological barrier before water circulates through the building.
- Assess storm risk in your area and monitor historical trends, especially if your property has aging infrastructure.
- Build storm-resilience into your water safety plan, including backup power for water treatment systems and routine Legionella risk assessments.
Storms are unpredictable, but your water quality response shouldn’t be. Be sure to take the time to prepare your building for the next storm before it hits.
