Reasons Why Cold Water Storage Tank Cleaning Is Essential

Cold water storage tank cleaning is essential to maintaining the quality of your water, whether potable or otherwise. Removing bacteria and ensuring regular maintenance can prevent various health issues that dirty water can cause. Dirt, mould, sediment, and harmful bacteria can all develop without your knowledge, so it is important to understand why storage tank cleaning and disinfection are essential. 

This article will cover contaminants and the recommended methods to clean your cold water storage tank. 


The primary reason why cold water storage tank cleaning and disinfection is necessary is due to various contaminants that can risk human health. The first of these contaminants is bacteria and pathogens. 

  • Bacteria and Viruses

If your water tank becomes infected with bacteria or viruses you could become ill with a stomach bug or even experience more serious illnesses. Ordinarily, severe effects only occur if your water has been stagnant for a long period or if your tank develops Legionella. 

  • Legionella

Legionella contamination causes thousands of cases of Legionnaires Disease each year, an illness plagued with symptoms such as high temperature, muscle pains, and occasionally pneumonia. Legionella thrives on rust, algae, sludge, and other organic matter in stagnant water. Unfortunately, dirty cold water storage tanks provide the perfect environment for the bacteria to grow. 

Legionnaires Disease is caused by inhaling small droplets of water suspended in the air but can be developed by consumption of contaminated water.

The most effective method of avoiding Legionella growth is to regularly engage in thorough cold water storage tank cleaning, to maintain the storage tank, and to ensure that the temperature of your water is maintained. Legionella thrives in temperatures of 20-50°C and theoretically shouldn’t be able to survive in a cold water storage tank, but can if not properly maintained. 

  • Biofilms

Biofilm formation occurs due to a reaction to UV radiation, limited nutrients, pressure, and salt concentrations. Biofilms can occur in water tanks, contaminate the water, and harbour pathogens. Cold water storage tank cleaning is essential to deter the formation of biofilms in your tank. 

  • Sediment

Sediment formation is a natural process that can’t be completely deterred by storage tank cleaning. It occurs when the metals present in your tank begin to dissolve and rest at the bottom of the tank. Sediment hasn’t been known to cause serious illness in humans. But can generate an unpleasant taste and odours in the tank. Despite not being a health hazard to humans, sediment should not be ignored. It can breed a host of issues in your water tank that can lead to malfunction or even total breakage. 


How does cold water storage tank cleaning work?

Firstly, it is recommended that your storage tank cleaning is scheduled at least once every six months. Doing this will ensure that the bacteria and pathogens that may be present in your water are killed or prevented from growing. Additionally, you should hire a trained professional to complete any work occurring inside the tank, as the confined spaces can pose a health risk. 

The storage tank must be empty before the cleaning process can begin. Once the tank has been drained: the internal surfaces should be scrubbed with hot water and detergent, and the external hoses, pumps, and pipes should be washed thoroughly. Before filling the tank, every surface should be washed with hot water until there are no traces of detergent left.

How do I disinfect a cold water storage tank?

A ratio of 50mg/L of household chlorine bleach is recommended to be used to disinfect the tank. As the tank is filled the bleach should gradually be poured into the water while being stirred thoroughly to ensure full coverage of the surfaces of the tank. The tank should be filled with water and mixed with bleach until it is at the normal operating level and left for at least 12 hours to allow the bleach time to penetrate any remaining dirt that may still be present on the surface of the tank. 

The tank should be drained and filled as many times as necessary to rid the bleach smell from every component of the tank. Once the smell is gone, the cold water storage tank cleaning is complete.

Water Tank Lining by COVAC

How to prevent further issues

Additionally, by ensuring to keep up with maintenance and have your tank thoroughly cleaned bi-yearly, there is another method of slowing the rate of dirt build-up. 

Water tank lining is one of the best ways to keep issues with your water tank at bay and reduce the need to endeavour in water tank cleaning so often. Poor condition water tank lining can contribute to the state of your water and help to exacerbate the problems you’re experiencing or prevent them from occurring. 

Here at COVAC, we specialise in water tank lining and are proud to offer exceptional tank lining services that provide our clients with long-term solutions to their water tank problems. We ensure that we leave your tank exceeding the current water regulations and standards. As well as be protected from erosion, corrosion, and leaking. 

Our services come with a 10-year guarantee, so you can be sure that you will receive the best possible cold water storage tank cleaning services from a trained, experienced, and fully certified team. We will ensure that your tank adheres to the HSG274 and ACoP L8 guidelines to help protect you and those around you from illness. 
So, why not contact us today for further information about our services?

  • Cert No. 22946

  • Cert No. 22946