[[Image:Handpump.jpg|thumb|right|300px|Liquid Gold - Children in the Central African Republic pump clean water from underground. Photo: Marielle van Uitert.]]
[[Image:pump altitude.jpg|thumb|right|300px|Example: a treadle pump is promoted as capable of lifting water from 23 ft. at sea level, the graph indicates that at 8000 ft elevation a loss of 8.8 ft. of suction capacity will result. The pump used at this elevation is now capable of lifting water from 14 ft. Chart: [http://www.pacificliquid.com/ Pacific Liquid & Air Systems.]]]
Many different kinds of handpumps are frequently installed on hand-dug wells and boreholes in rural areas, including many drought-prone areas. They facilitate a contamination-free method to extract water. Most pumps are positive displacement pumps and have reciprocating pistons or plungers.
==Construction, operations and maintenance==
[[Image:pump altitude.jpg|thumb|right|300px|Example: a treadle pump is promoted as capable of lifting water from 23 ft. at sea level, the graph indicates that at 8000 ft elevation a loss of 8.8 ft. of suction capacity will result. The pump used at this elevation is now capable of lifting water from 14 ft. Chart: [http://www.pacificliquid.com/ Pacific Liquid & Air Systems.]]]
'''General advice on cement''': A common cause of cracks in structures and linings (e.g. in tanks, dams, waterways, wells) is errors in mixing and applying the cement. First of all, it is important that only pure ingredients are used: clean water, clean sand, clean rocks. The materials have to be mixed very thoroughly. Secondly, the amount of water during mixing needs to minimal: the concrete or cement needs to be just workable, on the dry side even, and not fluid. Thirdly, it is essential that during curing the cement or concrete is kept moist at all times, for at least a week. Structures should be covered with plastic, large leaves or other materials during the curing period, and kept wet regularly.
