The EMAS pump is a very cheap PVC piston pump for family use, which can both pump water from a well and pump it to an elevated point. For example, it can pump water from 20 meters underground directly to an elevated tank another 20 meters above the ground level. The ability to pump directly to a storage tank avoids handling of the water, which avoids contamination.


The EMAS pump compresses water between two one-way valves (check valves produced with glass marbles), a footvalve and a piston valve. Water is forced up the piston tube and comes out of the pump handle.

History and social context

EMAS is the acronym for Escuela Móvil de Agua y Saneamiento (Mobile School for Water and Sanitation), in Bolivia, whose director, Wolfgang Eloy Buchner, developed this pump in the 1990's.
EMAS is not only the name of the mobile school for water and sanitation, but also a whole technical and social concept of water and sanitation which includes rain water harvesting, solar water heaters, windpower, hydraulic rams, water treatment, small tanks and sinks, a variety of hand and foot pumps, and ferrocement tanks. 

Suitable conditions 

The EMAS pump is designed for household water supply at family level. Large diameter models can be used for small scale irrigation if the water is very superficial.
Several variants of the EMAS pump exist, such as adaptations to shallow wells (larger diameter, higher output), very high pressure (up to 60 m head) and foot-operated balancing devices. It can be coupled to windmills, children's seesaws, animal roundabouts etc. An EMAS pump can fit in boreholes as narrow as 1.25", which means that cheap, hand drilled boreholes are possible, such as with the EMAS well drilling method.
EMAS pumps can be used to pump to a depth of 40-50 m. Deeper than 40-50 m, the pumping becomes very heavy. The EMAS pump can pump up to 30 l/min from a depth of 10 m, when operated by hand. Total production is up to about 5 m⁴/day. (That is: 5 m³ from 1 m depth or 0.5 m³ from 10 m or 250 l/day from 20 m depth etc.).
The lifespan of an EMAS pump can be estimated as 2 million liters pumped. PVC pumps are not as sturdy as metal ones. Ideally, they should serve a single family who owns and maintains it. Communal use is possible if maintenance and repair are well organized, but a single pump is not recommended to serve more than 100 people.

Advantages	Disadvantages/limitations
- Can pump directly into an elevated storage tank, avoiding water handling in buckets. - Can be built and repaired by users themselves - Very cheap (less than one tenth of a rope pump in Nicaragua)	- Less resistant to very intensive use and mistreatment than metal pumps. - Output is on down-stroke. That makes it slightly more complicated to fit a lever or treadle.

Some 20,000 EMAS pumps are in use in Bolivia and some 10,000 in Brazil. It is used in Peru, Equador and Nicaragua. In Asia and Africa, hundreds are in use.