Methods of irrigation are reviewed, including surface irrigation, sprinkler irrigation and drip irrigation, and the problems of these systems with regard to the quality of the water used are described. Surface irrigation does not suffer much from water quality problems, but both sprinkler irrigation and drip irrigation systems are more affected, the main problem being clogging of pumps, pipes and orifices. Clogging is usually due to a combination of suspended matter, chemical precipitation and biological growth. Current solutions through water treatment, and associated problems with this, are described, with examples given of typical strainers and filters. The key to the solution of clogging problems is a proper match between water quality of the source and within the distribution system, and the type ot treatment to be used, therefore, proper water quality monitoring is recommended. Direct granular filtration is the most preferaDle treatment process for drip irrigation systems.