Underground Polyethylene Cisterns
Advantages:
- Can be an economical underground storage solution for water
- Aesthetically pleasing option since the tank(s) will be out of sight
- Complete protection from any UV sunlight degradation over time
- Available in a wide variety of sizes and capacities
- Easily transported and installed with relatively small equipment
- Provides strength and durability for years of reliable performance
- Can be food grade, NSF approved for drinking water storage
Disadvantages:
- Tanks are only available up to about 2,500 gallons, meaning that if you wanted more storage than 2,500 gallons then you will have to install multiple tanks which increases the per gallon installed cost
- Excavation and the haul-off of soil materials to bury these cisterns can add a lot to the total cost of the rainwater collection system
- Cisterns can float out of the ground if not partially filled at all times or secured with deadmen
- May not be structurally sound to support traffic
- Cisterns may not be repaired easily
