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Drinking Water Tank Cleaning: Why Is It Necessary, and How To Do It?

While it is true that water replenishes us in numerous ways, a lot of diseases are caused if we consume water in impure form.  

The irony is that people often invest a lot of money in buying expensive water purifiers and other filtering equipment, but neglect entirely their water storage tanks’ hygiene.

Water filters and purifiers are secondary sources of water, while water storage tanks are the primary reservoir.

Improper or irregular cleaning of water tanks is important to ensure that they are free of bacteria, algal growth, and grime. 

Therefore, it is imperative to maintain the cleanliness of water storage tanks to ensure you and your loved ones’ good health. 

The article talks about the procedures required to follow to ensure that your water tank is safe and clean for use.

How Frequently Should You Clean Your Water Tank?

There are no hard and fast rules regarding when to clean a tank. It depends on various factors like:

  • The extent of sediment which comes along with the water, 
  • Water quality, 
  • The types of water tanks being used, 
  • The capacity of the water tank, etc.

In nutshell,  if your household water starts to smell and tastes different, or if you notice algal growth or slime build-up on the inner tank walls, it is time to clean your tank.

Usually, it is recommended to clean your water tank at least once a year (preferably every six months). If you live in a community where a larger volume of sediment comes along with the water, cleaning more often is suggested.

Source: Pexels

The sediments, rust, and dirt present in potable water are a source of nourishment for bacteria (like Legionella) and algae to grow on the walls. Here are some important reasons why cleaning a water tank at regular intervals is a necessity. 

1. Contaminated water is a leading cause of mortality

Sheer neglect to clean the water tank can sometimes result in catastrophic consequences.

Water from unclean sources is the 6th leading cause of death globally. It might sound strange to know that it comes just after cigarette smoking and alcohol consumption in the list.

If your potable water tank is not cleaned periodically, contaminants could seep into the stored water, which cannot be removed through water purifiers or other filtering mechanisms.

2. Unclean water harbours various bacteria

Poor water quality, unclean inner walls, sediment build-up, rust, etc can be a potential breeding ground for several bacteria, viruses, and algae.

Source: Pixabay

Poor water quality is the leading cause of diseases like cholera, typhoid, Hepatitis A or E, etc. 

3. Water filtration system won’t be effective if water comes from unclean tanks

Having installed a fully equipped water purifying system at your home is sometimes not enough to ensure proper drinking water quality. It is important to understand that your water tank is the primary water source. 

Water purifiers and filters can filter out harmful infections and particles but are not successful if the water tank is contaminated. Various bacteria and viruses pass through the filtration mechanisms and play havoc on human health. 

4. Helps to cut down maintenance cost

“A stitch in time saves nine”. 

Periodic cleaning and maintenance of your water tank is a more cost-effective and safe option than running to fix your water tank at the last minute. 

For various tanks like Hot dipped galvanized pressed steel tanks (HDG), Stainless steel water tanks, etc, rusting on the inner walls is a common occurrence.

If not maintained at the right time, it may lead to the development of cracks and leaks within the walls which may be a costly affair to manage.

Regular cleaning helps in preventing the deposition of rust. 

Similarly, water tanks like fiberglass type or plastic tanks are semi-transparent. This means that they allow partial passage of sunlight which provides favourable conditions for algal growth.

This again could be a costly condition to manage (not to mention, hazardous to the health) if overlooked for several years. 

Water Tank Cleaning Procedure

The following steps provide a thorough guide for cleaning drinking water tanks. 

1. Preparatory step – Inspection

  • If you are using a shared tank, it is required to inform the users beforehand that cleaning work will be undertaken.
  • Disconnect the tank inlet so that the water can be drained and the tank can be inspected.

2. Drain the water tank

  • Once the inlets are disconnected, the next step is to drain the tank completely.
  • Open the outlet valve and connect a water hose to drain out the water. If your tank is large, arrange a proper draining facility (to gardens or elsewhere) so that the water won’t overflow into the neighbouring areas.
  • Use any additional equipment such as a wet vac or hand pump to remove any leftover water. The water should be drained entirely to effectively clean the interior of the tank.

3. Thoroughly clean the interior

  • Once all the water has been drained out, you can see all the silt, slime, and dirt accumulated on the tank walls.
  • The next step is to thoroughly clean the interiors by using cleaning tools. High-pressure washers work the best by removing the stickiest of dirt.
  • Alternately you could also use adjustable hard-bristled brushes or cleaning equipment that can be applied at the required angle.
  • You would need basic supplies like rubber gloves, scrubbing brush, abrasive tools, bleach, detergents, etc.
  • To use bleach, ensure that it is diluted as per the norms (approximately 15ml per gallon of water). However, it is important to note that strong chemicals like bleach are not suitable for all types of tanks. Your tank supply and installation company can provide guidance on the best suitable cleaning agents for your tank type.
  • Pay attention to the corners as well as areas with joints or rivets.

4. Calculate the tank volume

  • Tank volume calculation is required to estimate the amount of chlorine or other disinfectants needed for cleaning. The dosage of chlorine required to disinfect the tank is dependent on its volume.
  • The following formula can calculate the volume for rectangular tanks:
    • Volume (litres) = L x W x D x 1000
    • Where D = depth of the tank (m)
    • W = width of the tank (m)
    • L = length of the tank (m).
  • This formula varies depending on the geometry of the tank.

5. Disinfection and chlorination

  • Once the tank is thoroughly cleaned, the next step is to remove all the harmful pathogens by chlorinating the tank’s water.
  • Sodium Hypochlorite should be added to the tank to achieve a level of 50PPM free residual chlorine in the tank.
  • Once the desired level of chlorine is achieved within the tank, the tank outlet should be opened to enable the water to flow around the system.
  • If you are using bleach, it is important to leave it for a couple of hours and let it do the action. This will help to clear off any harmful pathogens or contaminants harbouring inside the tank.

6. Disinfect the water supply lines

  • It is not just the tank walls and corners where silt deposition happens. You can see the accumulation within the water supply lines as well. Thus, it is imperative to sterilize water supply lines to ensure good water quality.
  • Run the same bleach solution that you have used to clean your tank through the supply pipes. This will help to remove any contaminants within the pipes and the joints.
  • Additionally, you could use a pump to run the solution through all the supply lines in your home.

7. Rinse the tank

  • Ensure that you thoroughly rinse off the solution with clean water multiple times, since the bleach is toxic and should never mix with drinking water. High-pressure hose pipes or water jets are best suited for the rinsing process.
  • If you have rinsed the supply pipes, make sure to run hot water through them to clear off any residual bleaching solution.
  • The chlorinated water can be neutralized by adding sodium thiosulphate.
  • Keep repeating the rinsing process until the water coming out of the tank is clear and free of the bleach odour.

8. Check the chlorine levels

  • To double-check that no residual chlorine is left inside the tank, use a chlorine strip to double-check the chlorine level inside the tank.
  • If the amount of chlorine in the water is found to be higher than the permissible limits for drinking water quality, you need to rinse the tank a few more times until the water is chlorine-free.

9. Refill the tank

  • Having followed all the tank cleaning steps, let it dry completely for a few hours.
  • Ensure that the tank lid is properly replaced to avoid debris falling into the tank.
  • Once the tank is dry, it is time to fill up your tank with pure drinking water.

Disposal Of Liquid Wastes

Irrespective of the liquids that you use for cleaning and disinfecting, it is important that you adhere to proper disposal mechanisms for disposing of these chemicals.

These chemical liquid wastes should not be discarded in water bodies or on the ground. Ensure that the wastes are disposed of in the designated sewers. 

Bottom Line

Ensuring a clean and pure water supply is necessary to safeguard the health of your family.

It is often noted that people fail to understand the importance of maintaining the health of their water tank when it comes to ensuring overall water hygiene. 

The article provides a step by step guide to cleaning your water tank.

However, it is not always advisable to take up the process yourself, especially if you are not proficient with the use of chemicals and tools. Additionally, climbing inside your water tank may be hazardous due to the presence of an anaerobic environment inside.

Cleaning and maintaining the tank while keeping safety procedures is vital. It is advisable to consult with a reputed water tank supply and maintenance company to get a professional job done. After all, we’re talking about the health and hygiene of your loved ones.

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