Quick Answer
Cisterns are often misunderstood, and many people believe that cisterns are a safe and maintenance-free way to store rainwater. However, cisterns can be a breeding ground for bacteria and mosquito-borne diseases if not properly designed and maintained. Improperly constructed cisterns can also contaminate the stored water.
Inadequate Waterproofing and Liner Failure
A common misconception about cistern safety is that a simple layer of tar or a thin liner is sufficient to prevent water from seeping into the surrounding soil. However, a minimum of 30 mils (0.76 mm) of high-density polyethylene (HDPE) liner material is required to prevent liner failure. Additionally, a 3-foot (0.9 meters) wide concrete apron around the cistern is essential to prevent water from entering the cistern through the soil.
Inadequate Ventilation and Mosquito Problems
Another misconception is that a cistern can be safely ventilated with a simple pipe sticking out of the top. However, a minimum of 12 inches (30 cm) of screen-free ventilation area is required to prevent mosquito infestations. Regular cleaning and maintenance of the cistern’s ventilation system is also crucial to prevent mosquito breeding.
Inadequate Maintenance and Water Testing
Lastly, many people believe that cisterns can be left unattended and still provide safe drinking water. However, cisterns require regular testing for pH, turbidity, and bacteria levels, as well as regular cleaning and maintenance to prevent contamination. This includes inspecting the liner and surrounding concrete for any signs of damage or erosion.
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