Simple Pump: The modern hand water pump.
Possible leaching of iron in cheap pumps.
Initial Cost or Total Cost of Ownership: Page 4
Added Risk and Cost to Consider: Iron content leached from galvanized iron pumps
Most Mark II/III/VLOM hand water pumps are installed with galvanized iron that makes contact with the water being pumped. When the water is acidic, the risk to people's health is increased.
A conversation with a groundwater treatment expert who had just returned from a developing nation left us initially mystified. He mentioned that, although the water from pumps was safe to drink (when the pumps were not in disrepair), the people used water from pumps for every purpose except drinking water.
A paper on iron removal from drinking water then identified the likely reason well water was not being consumed. (2)
First, the paper notes
"As a drinking water source groundwater is often considered as better than surface water because it does not contain harmful pathogens and generally does not need treatment. However, in many locations it contains iron, either from geological formations or from iron pump components. Iron is not harmful to health, but causes people to reject the borehole water, mainly because it tastes bad and stains clothes, containers and skin. When this happens in rural areas in developing countries people return to drinking surface water and this can result in disease and death, especially for young children."
That same paper cites a UNICEF engineer, saying that
"...experience from hundreds of iron removal plants in India show that [galvanized iron] causes bacterial oxidation and reduction cycles to take place which result in increased iron concentrations in the outlet water. This problem can be eliminated by replacing the GI parts with PVC and stainless steel..."
Data from that engineer's three-year study of nine Mark II pumps showing iron levels mostly below the World Health's Organization's (WHO) 0.3mg/liter guideline maximum for pumps using PVC in lieu of galvanized iron. Those without the PVC-for-galvanized-iron replacement were substantially more likely to be significantly over the WHO standard, and therefore to produce bad-tasting water.
Some manufacturers of Mark II/III/VLOM pumps offer PVC parts as pipe options, promoting the merits of it use rather than galvanized iron. From one manufacturer's site, using words we could have written to express one of Simple Pump's advantages,
"The Stainless Steel Advantage: While the initial cost of SS component could be 3-5 times higher than its MS/Gun Metal/CI counterpart, it more than pays for itself in no downtime cost..."
Ironic! The apparent savings in the initial purchase are, again, eliminated, this time by the cost of actually making the drinking water palatable and safe.
The situation is exacerbated if the groundwater to be pumped is at all acidic. It is then predictable that iron will leach from the galvanized iron used in most Mark II/III/VLOM pumps. Just as current NGO procurements emphasize minimizing up-front payments to the detriment of overall project costs, whether proper water testing is performed prior to pump installation can be hit or miss. The failure to ensure adequate funding for this expertise is a risk imposed by the use of Mark II/III/VLOM pumps, and therefore an additional cost to account for.
On the other hand, Simple Pump is made completely from lead-free components that are Safe Drinking Water Act compliant. All metal parts that make contact with water are stainless steel and are manufactured precisely using computer numerical controlled (CNC) machines. The pump rods are high tensile fiberglass and the drop pipe is Polyvinyl Chloride (PVC) schedule 120. The only metal making contact with the water is completely lead-free, CNC-machined stainless steel.