What are the disadvantages of a solar water pump?

Advantages

Low Operation costs since fuel is not needed and system run on sunlight

No dependency on erratic or expensive fuel chain supply (avoid also the risk of fuel theft)

Low regular maintenance requirements since solar panels and invertors have no moving parts

No pollution or noise produced

Extended lifetime (good quality solar panels are warrantied for 25yrs, invertors typically 6-8 years)

Disadvantages

Capital costs typically higher than equivalent diesel solutions. However systems prices are increasingly dropping

Most of application need water storage typically larger than for equivalent diesel systems

Risk of theft of panels, that are still seen as a valuable commodity in some locations

System is dependent on solar radiation levels

Typically spare parts and knowledgeable technicians are only available at capital level