Inspecting your tanks and towers After the Storm        By Ron Perrin

Sediment builds up in almost all water storage tanks and towers over time. This soft accumulation can be a welcome breeding ground for a number of microbes including Legionella, Salmonella, E. coli and many more.

After a storm comprehensive inspections of the facilities should be done as soon as it is safe to do so.  Any breaches should be repaired.  If your tank has, or had, a breach, it is more likely to also be a victim to some sort of microbial contamination. In fact a few years ago while attending a five state meeting on drinking water at USEPA Region 6 headquarters in Dallas, I heard an USEPA official refer to sediment on the interior floor of water storage tanks as a breach.  He said you should treat sediment the same way you would treat any other breach in your system. While you would repair a hole in the tank (a common breach), when found sediment should be removed.

To understand why the USEPA thinks of sediment as a breach in the system you only need to look at what kind of contaminants can use sediment as a habitat. The list of possible microbial contaminants that can attack your water system is too long to include here. According to the CDC the most common contaminants are listed below.

Top 10 Causes – Outbreaks in Public Water Systems*

Giardia

Legionella

Norovirus

Shigella

Campylobacter

Copper

Salmonella

Hepatitis A

Cryptosporidium

E. coli, and excess fluoride (tie for 10th place).

#1 Is Giardia, this is a nasty looking bug. A microscopic parasite that causes the diarrheal illness known as giardiasis.

Giardia

Photo: Giardia CDC

Removing accumulated sediment from the floor of your tank removes the habitat that microbes can use to get a foothold in your system. After the sediments are removed chemical treatment becomes more effective, and more often than not, less chemicals are needed to meet standards after the cleaning. After heavy storms with high winds and flooding, water utility systems are at high risk of contamination, and RTCR violations increase by dramatic numbers.

Be pro-active, keep your system safe and REDUCE your chance of having a wide-spread contamination or RTCR violations by inspecting, and if needed, cleaning your tanks.

If you do have an RTCR violation, an assessment is required. We suggest making an underwater tank inspection part of your assessment. If sediment is found in your tank, cleaning would be the corrective action you need.

The bottom line is this: After severe storms your water storage facilities need a comprehensive inspection inside and out. If you find breaches, repairs need to be made. If you find accumulated sediment in your tank, treat it like the breach that it is and remove it from your system.