By James Peterson

Hurricane season is upon us and those living in at-risk areas are keeping a close eye on weather forecasts in anticipation of the next big storm. In recent years, the US has experienced several destructive hurricanes that have caused billions of dollars in damages, including Harvey, Camille and Katrina. While the immediate concern during any major natural disaster is human safety and loss of property, after the storm passes, the lingering effects on our water quality can have long-term health impacts.

From lack of access to safe drinking water to untreated contamination that can lead to serious illness, there are significant post-disaster risks to our water quality that can impact the overall health of residents in affected areas. It is important to understand the causes of these risks in order to properly address post-disaster water issues. In most cases, correcting water-safety issues close to or at the point of consumption is most effective.

What happens during storms
Hurricanes and tropical storms bring large amounts of rainfall in a short period of time. The average rainfall during a hurricane is 16 inches (40.64 cm), although the total can be much higher with more severe storms. For instance, Hurricane Harvey set records1 with a total rainfall of 60.58 inches (153.87 cm); that does not include the ocean water that struck land due to high wind speeds. As a result of heavy rains, sewer and rainwater systems become backed up and cause flooding, inviting everything in the surrounding area to enter the flood water. This could range from physical contaminants such as dirt, trash and animal waste, to unseen contaminants such as microorganisms and bacteria.2

Flood waters, rife with contaminants, often submerge drinking-water infrastructure and in many cases, parts of building plumbing. While ideally this equipment is airtight, small leaks are inevitable, particularly with aging infrastructure, combined with the fresh damage caused by the storm. These unintentional access points enable flood water to enter the water supply, putting people who rely on these systems for clean, safe drinking water at risk for both short-term and long-term illness.

Private wells or small and very small water systems sourced from groundwater within the flooding area have the same risks in floodwater intrusion to infrastructure and plumbing, but can also face a more lasting issue of the original groundwater source becoming contaminated from floodwater intrusion. With many of these systems lacking full-time management, identification and remediation of contamination can also be significantly delayed compared to larger municipal systems.

How to address water contamination
There are several ways to remediate or at least mitigate water safety issues following a natural disaster. Municipalities can—and arguably should—issue immediate boil or do-not-use warnings for appropriate water systems. More importantly, it is critical that residents heed these warnings. Residents on private wells or systems small enough to not have around-the-clock management should consider responding similarly at the first signs of regional flooding, as issuances of warnings may be delayed. Some impacted locations may also be required to rely on alternative water sources, such as bottled water for a period of time and well-water supplies may be faced with state or regional recommissioning requirements. Flushing all water outlets can also help to remove a majority of mixed drinking and flood water from building plumbing after boil warnings are lifted. In addition to these tactics, any purification or filtration cartridges that had been installed during the flood or warning periods should be discarded and replaced. While water may look clear upon dispense, the filter could be damaged from increased water contaminants or harboring a growing number of microorganisms. To be even more sure of detecting potential contaminants, water systems could be outfitted with sensors that can monitor3 and even alert for unsafe levels of specific microorganisms.

While these remedies can help address immediate water safety concerns, the prolonged presence of contamination within a water system can lead to the growth4 of microorganisms and bacteria within the infrastructure. Flushing this more stubborn bacteria may take much longer than expected and there is a chance it may continue to harbor organisms despite continued remediation efforts. In terms of the health risks, while a relatively healthy individual is less likely to experience problems from ingesting small amounts of these microorganisms, a visit from an elderly, infant or immunocompromised person could result in an infection due to a weaker immune system.

These remediation efforts can take weeks, if not months, to implement and fully complete before the affected areas can begin to trust their water supplies again. And even when the water is again safe to drink, the next big storm system may be on the way.

Increased frequency of high-scale flooding
Instances of severe storms and major hurricanes are increasing, inundating coastal communities with flood waters more regularly. Research5 has shown a significant increase in Atlantic hurricane activity since the early 1980s as measured by intensity, frequency and duration, as well as the number of Category 4 and 5 storms. In addition, more frequent and widespread drought periods and damage to natural rainwater management systems (such as wetlands, urban waterway burying, increased non-permeable land) create more scenarios for water contamination, even in inland communities. For example, rainfall that hits areas that have been experiencing dry periods can quickly lead to flooding. Ultimately, these more frequent and intense storm patterns are not going anywhere and their impact on water systems will persist. As a result, we need to consider stronger, more sustainable solutions to ensure water safety in post-disaster situations and sustained action on improved stewardship of both our natural and drinking-water resources to reduce the impact of our changing climate.

Methods to remain resilient to post-disaster water risks
While your water utility may claim that they are once again producing clean and safe water, that is only one piece of the puzzle. Even if municipal water infrastructure has been restored to normal working conditions, building pipes may not have been repaired properly or in a timely manner, forcing constituents to continue to rely on alternative drinking sources and safety measures. Homeowners and businesses can prepare for a weather-related impact to water safety by installing point-of-use solutions preemptively, disconnecting water during storms and/or waiting until utility warnings are lifted to ensure that the water no longer poses a risk.

As storm systems continue to increase in frequency and intensity, the ability to rebound as quickly as possible is critical for mitigating the long-term health impacts of unsafe water. Supplemental disinfection in homes with solutions like UV or advanced filtration is becoming an increasingly attractive addition to water safety at the consumer level. With advances in technology, treating water at the point of dispense with technologies like UVC LEDs can help assure that concentrations of residual microorganisms are reduced directly at the closest point to consumption and help assure consumers that despite external factors like flooding and slow or unfinished maintenance, they can still trust that the water coming out of their taps is safe.


  1. National Hurricane Center Tropical Cyclone Report Hurricane Harvey (AL092017).
  2. Bacteria. Klaran.
  3. Water Quality Monitoring. Optan.
  4. Biofilm Prevention. Crystal IS.
  5. Changes in Hurricanes.

About the author
James Peterson is responsible for the strategic direction of Crystal IS products focused on water markets. He develops business models for UVC emitters and ensures these product lines meet specific customer needs in water markets. Prior to Crystal IS, Peterson co-founded Vital Vio, a company that designs, engineers and manufactures LED lighting systems that reduce bacteria and other organisms from at-risk environmental surfaces.

About the company
Crystal IS, an Asahi Kasei company, is a manufacturer of high-performance UVC LEDs. The company’s products are suitable for monitoring, disinfection and sterilization in a variety of applications, including commercial and consumer POU water purification, as well as infection control in air and on surfaces in healthcare industries. For more information, visit


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