The area should be suitable for [[rainwater harvesting]]. Depending on the design the capacity of the tank varies from 3,500 to 20,000 liters.
{{procontable | proborder="1" cellpadding="5" cellspacing="0" align="center"|-! width="50%" style="background:#efefef;" | Advantages! style="background:#ffdead;" | Disadvantages|-| valign="top" | - Low cost alternative to metal or ferrocement tanks.<br>
- Good for areas where ground would otherwise be permeable.<br>
- Unaffected by freezing weather. <br>
- Using rainwater tanks regularly may reduce storm water run-off from your field. This may reduce flooding, erosion and environmental damage to streams.<br>
- They work well when privately owned and maintained.<br>
| convalign= "top" | - Sub-surface tanks often cannot hold enough water for whole dry season. Making bigger berkeds is possible but more difficult and cost is high (unaffordable tank is not replicable on larger scale).<br>
- Flotation of the tank may occur in areas with a high groundwater table.<br>
- Heavy vehicles driving near to tank can cause damage.<br>
- When built in a remote area, construction is difficult due to lack of water and large distances to transport materials.<br>
- Water quality is likely to be unacceptable for direct consumption, treatment recommended.
}|}
==Resilience to changes in the environment==