* The rock that makes up the catchment should be bare and free of vegetation/soil. It should have no fractures or cracks that would result in a loss of water through seepage.
* Site the dams for rock catchments to maximize the natural topography – to get the best volume, make dams on the lower side of existing rock pools.
{{procontable | pro=
- High runoff coefficient = similar to roof catchments in that even small showers produce water <br>
- Minimal seepage <br>
- Maintenance is simple and cheap <br>
- Rock catchments do not occupy farmland and often no one owns the land, so it easy to implement<br>
| con=
- Not many sites suitable <br>
- If building tanks that store water directly, storage capacity is limited compared to an open reservoir<br>
- Cost is high – experience from Kenya shows that a 56 m3 dam cost $4,000 including labour (= $71 per m3 of storage) <br>
- Vectors can breed in open water<br>
- Microbiological and chemical water quality is likely to not be acceptable for direct consumption (see “Natural ground catchment & open water reservoir”)
}}
==Construction, operations and maintenance==