Many human diseases are caused by contaminated water. This is why it is especially important for people using their tanks for drinking water to know how to keep them clean. Water contamination can be prevented with the right care. It is important to clean your water tank on a regular basis, about once a year is best. This will also ensure post-tank filters are not over-burdened. A regularly cleaned water tank, properly maintained roofing and gutters, and proper pre- and post-tank filtration are the best way to maintain a safe, clean supply of water.
Household water tanks are supposed to provide safe water for cleaning and gardening, and sometimes cooking and drinking too. Tanks need be regularly cleaned, but unfortunately many people do not know how to keep water tanks clean. Over time sludge or sediment may build up, which can contaminate your water and cause illness.
When it comes to cleaning the tanks you have a few options – you can clean the tank yourself using just water. Or you can use a more advanced method – high pressure water jet cleaners along with anti-bacterial solutions and disinfectants. The third option is to hire a professional to clean the tank. There are many companies that specialize in cleaning water tanks. For large tanks at or above 5000 litres, or for heavily soiled tanks, this may be the best option.
In this example we use chlorine as a cleanser. Some experts suggest the use of HTH chlorine which is known to be effective in disinfection. Although an effective cleaner, chlorine is highly toxic so please read and follow safety directions carefully, including wearing appropriate protective gear. However, chlorine is not the only potentially toxic cleaner so make sure to carefully read the safety directions on any chemicals you use, and wear appropriate protective clothing when using or handling them.
The first step in cleaning the tank is to switch off the valve that supplies water through the pipe near the top of the tank. Tanks that are manufactured to harvest rain water do not usually have this switch so skip this step if you have a rain harvesting tank without a valve switch.
Next, open the outlet used for draining on the tank and empty it of as much water as you can. One good way to do this is to attach a hose pipe to the draining point. This allows the flow of water to be directed to a predetermined location, avoiding waste and damage to the soil. This will take some time, especially when the water tanks is large.
After successfully draining the contents, the next step is the removal of the access hatch at the top of the tank. After removing the hatch, clean the interior with pressurised water to remove the build-up of sediment on walls and the bottom of the tank. After the first rinse, a trusted anti-bacterial solution can be added to the pressure washer for a more thorough cleaning of the interior.
After the application of the chemical, let the chlorine stay inside the tank for at least 12 hours. After this the tank should be emptied of water and then refilled. The water should be left for half an hour and then tested for residual chlorine levels. For readings of 0.5 mg/l or less, the water becomes safe for consumption. If the reading is higher, the tanks should again be drained and refilled and the testing process completed. Once the water has acceptable levels of chlorine and the tank is reconnected to the pump and any other power outlets the process is complete. This is just a guide, please seek specific professional advice before cleaning your water tank yourself, with chlorine or any other chemical.