The first one is the system requirements of the water.
When considering drip irrigation system, no matter with drip tape, drip line or drip pipe, the most important thing is anti-clogging. Organic and inorganic particles, impurities, etc. in the water will block the dripper outlet of the dripper system, destroy the uniformity of irrigation, and increase the maintenance cost. Therefore, it must be ensured that the water entering the irrigation system is free of these particles. In actual operation, a sedimentation water tank is generally set up, and river water, well water, etc. are precipitated in advance, filtered by filter system of 120 mesh （130 microns level）or more, and then injected into the irrigation system.
The irrigation filter system usually combines primary filtration device (Sand Filter a for river water, and hydro cyclone sand separator (centrifugal type filter) for well water) and secondary filter (mesh filters or disc filters). If the water is very good quality, the mesh filters and disk filters can also be used as the primary and only filter in the drip irrigation system.
In addition, although the drip irrigation pipes and the main pipe of the drip pipe system are generally made of plastic materials (PE, PVC, POM) that are resistant to salt and alkali corrosion, the water with too high salinity is easy to form crystals at the drop emitters, causing blockage. In this condition, it is necessary to consider cleaning the pipes with weakly acidic water with a pH value of 5.5-6.0 after the drip irrigation system has been used for a period of time.
The second one is the common requirement of the irrigation water. Itdepends on the needs of the crop being irrigated, mainly pH, water salinity (EC), sodium adsorption ratio (SAR), etc., regardless of whether a drip irrigation system used or not.