How to clean, maintain an underground tank

Many people have embraced underground water tanks in a bid to manage the high water bills or water scarcity, depending on where they reside.

Underground tanks have gutters that are connected to the house which trap rainwater from the rooftop and channel it to the tank.

Sometimes homeowners think that after constructing the tank, their job is done. They do not clean the tank and the net that covers the water path to ensure it does not harbour reptiles like snakes, frogs and lizards, says Lawrence Kawuma, who constructed one. Kawuma cleans his tank during the dry season when the water levels are low, or when there is no water at all.

‘‘When the dry season sets in, I draw out all the water from the tank, scrub it with soap and water and dry it. I then cover it tightly to wait for the next rainy season,’’ he explains.

In order to prevent dirty water from entering the tank, when it starts raining, the gutters - which trap the water from the roof and channel it to the underground tank - must be removed and left out of the tank for at least three rainy sessions before placing them back.  

Brian Katimbo, a plumber says after cleaning the tank, some clean water must be left inside it to keep it moist in order to prevent cracks that may be result during the dry season. Katimbo explains that the cracks damage the tank, which then loses water through the walls.

He adds that when a tank is built, it can stand for five to eight years before the need to be repaired, depending on how it is maintained.

Osbert Luyinda, a construction engineer says compared to surface tanks, underground tanks are cheaper to install because of the low cost of reinforcements needed during construction because of the ground’s support and the strength it provides to hold the water.

“Many people buy small pieces of land these days and want to fix everything they need, like a source of water, a flower garden, a vegetable garden and also have a compound to relax in.

This makes an underground tank appropriate because the space above ground is limited. An underground tank stores larger volumes of water. Its water is sometimes cooler than the one above the ground,’’ Luyinda says.

However, he cautions homeowners to take extra care with hygiene because underground tanks are liable to contamination from running rain water.

Also, young children and tiny domestic animals can drown in the tank if it is not covered. Luyinda also explains that leaks in an underground tank can be difficult to detect and tree roots that are near the tank can damage it from beneath.

‘‘If the tank was constructed in the front of the home where heavy vehicles pass, they can cause damage to it,’’ Luyinda warns.