Dew collection


Dew collection in areas where the day-night temperature difference is > 12 °C. It utilizes condensation on sloped surfaces through natural radiative cooling. The condensate is collected through a gutter in a reservoir. An optimal collecting surface is hydrophilic and thermally isolated. Galvanized roofs can be improved with special coating. Risk of contamination with suspended solids.


If a suitable roof is already in place, costs are low. Advanced dew collectors are expensive, up to USD200/m2. For poor households, investment costs are possibly too high, especially if applied as a supplementary technology to another water supply method.


Because of low water yield, dew collection is suitable for household- or shared household-level. It can best be managed at household level. Since O&M does not require specific skills, no external support is needed.


Can be applied in regions with large parcels of unused land and large diurnal temperature changes (>12°C difference day-night). Collection not affected by drought. Water quantities are small and vary during year. Collection rates in Spain and Morocco between 20-70L/m2/yr.


Dew collection has very low O&M requirements. For construction, the condensing surface must be sloped, hydrophilic and isolated. And elevated surface can potentially collect more water. After construction the condensing surface, gutters and reservoir should be kept clean.


Potentially good water quality, but there might be contamination in drains or reservoir. Chlorination can be applied in reservoir. Roofs might not be suitable for dew collection. More research results are needed before dew collection is broadly disseminated.

Relevant remarks:

No relevant remarks for Dew collection.