If explicit water purification is needed, then solar power systems can operate them as well. Systems that operate on the basis of reverse osmosis, UV irradiance, or chlorine can all be operated directly by photovoltaic power systems. Water can be pumped from nearby streams, canals or lakes to irrigate fields. Or it can be drawn up to the surface from even hundreds of feet. Photovoltaic systems can be permanently mounted in the fields, be portable so they can serve multiple farmers, or be moved to different fields as needed.
Drip irrigation is more efficient than flood irrigation and is especially suited for hot climates.
However, it involves more equipment and is more expensive. Photovoltaic power systems can operate the pumps as well as the pressurizing systems to pass water through filters that are often needed for drip systems. In general solar water pumping for irrigation is not competitive when compared to diesel pumping. An irrigation system usually requires a large amount of power for a short seasonal period, whereas solar water pumping has its greatest advantages with small scale year-round use. However, there are niches for PV pumping with such applications as micro irrigation for vegetable gardens and plots of less than 1 hectare.