Tips To Effectively Clean A Concrete Underground Water Tank

Concrete custom-sized tanks are known to be perfect for keeping the water cool all year round because plastic and metal can heat up pretty quickly during the hot summer season. However, concrete is a better option for storage, but because of its porous nature, it can be a breeding ground for E. coli, algae and other kinds of microbes.


Sludge is also a common occurrence. Plant material, sediment and waste tend to reach the bottom of concrete tanks even after using strainers. Over time, it can accumulate and result in numerous health problems to people ingesting the water.


As a result, it is important to regularly inspect every underground water tank and have them cleaned appropriately. There are several steps to consider to ensure the cleaning is done correctly. Let’s take a look at these steps:


Step #1 – Turning off and draining the water supply


If there is an external water source that feeds the tank, it needs to be turned off before beginning the cleaning process. In case of a rainwater catchment system, there won’t be an external water source.


Now, the remaining water in the tank needs to be emptied before cleaning. As it is never a good idea to waste water because of the frequent shortage in water supply, it is best to have the water transferred to holding barrels. Though it isn’t safe for human consumption, it can be used for washing cars, watering the lawn and similar activities.


If it is not possible to save the water, it is essential to carefully drain it far from buildings, as it can oversaturate the ground and seep into basements and other building structures.


Step #2 – Cleaning the catchment area


For a system that is a catchment-type tank or cistern, it is essential to clean the exteriors where the rainwater tends to make contact before cleaning the inside. Soapy water with bleach is excellent for scrubbing the exteriors using a stiff brush. Once it is done, it should be rinsed with clean water.


Step #3 – Getting inside the tank


The access hatch should be opened, preferably using a wrench. If the cleaning process requires a person to climb inside, it is best to find professionals who are certified to work in confined spaces because the oxygen levels are often low.


People who plan on doing it themselves should ideally have a buddy by their side in case something goes wrong. The debris and sediments can be spotted using a flashlight, so keeping one on hand is advisable.


Step #4 – Cleaning the tank


An unscented liquid bleach with water should be enough to clean an underground water tank. A stiff brush is ideal for scrubbing the inside parts of the container properly. Once the job is done, clean water should be used for rinsing it.


Step #5 – Disinfecting the tank


Though water and bleach will be used again, the cleaning step should not be ignored because the surface needs scrubbing to remove all biofilms and sediments. After the cleaning process, the water tank will require a refill of potable water. It should also have liquid bleach, but in a higher concentration as it is necessary for the disinfection process.


It is ideal to go with a 5% to 8.25% strength of bleach with respect to every 100 gallons of water. It is essential to allow the water-bleach mixture to remain in the tank for about 12 hours.


Step #6 – Draining the tank


After the soaking phase is completed, the water inside the tank needs complete draining. The bleach can easily damage gardens and laws, so it is best to empty the water into street lawns. Some people may add potable water to run their faucets to get rid of the bleach’s scent, but certain health boards advice refilling and draining the tanks at least once or twice to remove the bleach.


Once it is done, water can be added with a tiny amount of bleach to prevent microbial growth.


Step #7 – Investing time and energy in maintenance


Concrete water tanks should ideally be cleaned every year. After it is done, regular testing is necessary for ensuring that the water is not infected.


By following these few simple steps, it is easy to efficiently clean an underground water tank for future usage.