The investment cost per capita is lower for communities of between 1,000 and 5,000 inhabitants if small piped systems with pumps powered by electricity from the grid or diesel engines are installed instead of handpumps. Only one or two high-yield wells will be required. In the size range of 1,000 to 2,000 inhabitants, piped systems with solar pumps are attractive, especially if the pumping lifts are low. Contrary to grid or diesel-powered systems, solar pump systems have no energy costs, but their application can be limited due to the high cost of photovoltaic panels – thus the number of panels needed is a determining cost factor.
==Handpump types======Reciprocating handpumps====
The majority of handpump types used worldwide belong to the group of reciprocating pumps. The water is lifted by a piston that is raised and lowered inside a cylinder that has a footvalve. The piston (or plunger) is moved by a pump rod connected directly to a T-handle or a lever handle at the pump head. In some pump types, a flywheel with crankshaft is used to create the reciprocating movement of the piston.
The function of the reciprocating pumps is based on the principle that water flows from areas of high pressure to areas of low pressure. The reciprocating pump creates an area of sufficiently low pressure above the body of water, causing it to flow upward.
===='''Suction pumps==== '''<br>
In a suction pump, the cylinder is above the water table, usually near the top of the pump head. The rising main extends below the water table. When the pump is operated, during the upwards stroke it appears that water gets “sucked up” through the rising main into the cylinder. In fact, the atmospheric pressure forces the water into the area of low pressure underneath the piston. The theoretical limit to which the atmospheric pressure can push up water is 10 metres (m). In practice, suction pumps can be used to lift water up to about 7 or 8 m.
The advantage of suction pumps is that the cylinder is normally above ground, and thus easily accessible. Maintenance involves replacement of seals and valves, operations that can be easily performed with few tools.
'''Examples of suction pumps include:''' [[No. 6 pump]], [[Rope pump]], [[Rower pump]], [[Treadle pump]], [[Super MoneyMaker pump]], and [[MoneyMaker hip pump]].
===='''Direct Action handpump===='''<br>
[[Image:DirectActionHandpump.jpg|thumb|right|300px| Direct action handpump mechanics. Drawing: WHO.]]
The pump is operated by moving a handle up and down. As the plunger is located underwater, no priming is needed. Adults, and even children, can pump the water, although if the water table is further than 5 m deep, this may be difficult for children. The pump stand and site must be kept clean.
'''Specifications:''' <br>
* Range of depth: 0–12 m.
* Yield: 0.25–0.42 litres/s at 12 m depth.
* Area of use: Rural and low-income periurban areas, where groundwater tables are within 12m of the surface.
'''Examples of the Direct Action handpump:''' [[Tara pump]], [[Malda pump]], [[Nira AF-85 pump]], [[Canzee pump]], [[EMAS pump]], and the [[PVC pumps]] have a direct action version.
===='''Lever Action handpump===='''<br>
Most deep-well handpumps are of the lever action type. The increased length of the water column in deep boreholes requires more effort to draw water and the lever of the handle makes the operation easier. Besides the conventional handle, there are also pump designs, which use a flywheel to operate a crankshaft for transforming the rotation into an up-and-down movement.
'''Lever action pumps consist of:'''<br>
1. above-ground components like pump head, pump stand and handle, which are usually made of welded mild steel components, preferably with a corrosion protection of hotdip-galvanized zinc layer.<br>
The configuration of the down-the-hole components can include an open-top cylinder. The plunger and the footvalve can be removed from the cylinder without dismantling the rising main. Or they can feature the conventional configuration with a small diameter rising main and a bigger cylinder diameter, which requires dismantling of the rising main for repairs on plunger or footvalve.
'''Examples of a Lever Action pump include:''' [[Kabul pump]], [[Jibon pump]], [[Walami pump]], [[U3M pump]], [[Afridev pump]], [[Afridev with bottom support]], [[Indus pump]], [[Pamir pump]], [[India Mark 2 and 3]], and the [[Bush pump]].
====Rotary handpumps====
The most commonly used rotary handpumps are the [[rope pump]] and the progressive cavity pump (very difficult for local technicians to maintain). Note that although some reciprocating pumps use a circular action mechanism to drive the pistons, they are not categorized as rotary.
====Diaphragm pumps====
[[Deep-well_diaphragm_pump|Diaphragm pumps]] are pumps employing a flexible diaphragm that is expanded and contracted to displace water. The advantages of diaphragm pumps are that they are easy to install, because no heavy mechanical parts are used. They can also be made corrosion-resistant through the use of plastic
hoses instead of metallic rising mains.
The disadvantages are that diaphragm pumps need high-quality rubber diaphragms, which are costly to buy and replace, and they have a relatively low efficiency because of the energy needed to expand the diaphragm on every stroke. In addition, the working principle is relatively complex so mechanics and caretakers need to complete comprehensive training programmes.
'''Example of a diaphragm pump:''' [[Vergnet Hydro]]
==Suitable conditions==