"While the overall climate is generally mild or temperate and fairly uniform, and rainfall averages about 1270 mm … per year, the water is rarely held for long by the porous soil and periods of drought are known.

Drought on Rapa Nui is brought about by extended periods of low precipitation compounded by winds which cause increased evapotranspiration.

The most dependable sources of water are the crater lakes (rano), but reservoirs (puna) were dug by the Rapa Nui along some parts of the coast.

Several European observers commented upon the lack of drinking water on the island, and on the Rapa Nui ability to tolerate brackish water which they found distasteful. Many Polynesians living on atolls routinely drink extremely salty water.

Fresh rainwater is said by contemporary Rapa Nui to have been caught in archeological features which are square or round catchment basins pecked into bedrock, rock outcroppings or even fallen statues.

These features, along with stone bowls of either basalt or red scoria, are today known as taheta."

 (Van Tilburg)