Every failed drip network we have been called to audit had a working pump. What it did not have was a filtration stage sized for the water it was actually drawing.
The specification gap
Filtration is usually specified from a catalogue figure for the pump’s flow rate, not from a water analysis. Canal water in the second half of the season carries a different load than the sample taken in spring — more organic matter, finer suspended solids, and an algae fraction that a disc filter will pass and an emitter will not.
A filter sized for spring water is a filter that fails in August, which is the month the crop cannot survive without water.
What to check before you buy
Two water analyses, not one
One at the start of the season and one at peak. Specify to the worse of the two, with margin.
Backflush trigger on pressure differential
A timer flushes when the filter is clean and does not flush when it is blocked. A differential switch does the opposite, which is the point.
A sampling point after the filter
One valve and a jar. It is the cheapest diagnostic on the whole network and almost nobody fits one.
If the network is already blocking
Acid or chlorine treatment recovers partially blocked emitters, but it is maintenance, not a fix. If the block returns within a season, the filtration stage is the problem and no amount of flushing will change that.
