Guide · Fundamentals
How Drip Irrigation Works
A drip system is not a pipe with holes in it. It's a chain of decisions — the source, the filtration, the pressure, the pipe sizes, the emitter spacing — where each link has to be right for the field to be even. This is the chain, end to end.
The idea in one sentence
Drip irrigation delivers water (and feed) in small amounts, slowly, directly to the plant's root zone — instead of flooding the field or spraying the air. The benefits follow from the mechanism: less water lost to evaporation and runoff, the weed line kept dry, the feed delivered where the roots are, and the labour concentrated in the schedule rather than the carrying.
What the mechanism doesn't do for you: decide your schedule, clean your filter, or survive an undersized pump. Those are the system's other links, and this guide covers them all.
The system, from source to plant
Every drip system — a container farm or a fifty-acre block — has the same five sections. The order matters, because each section exists to protect the one after it.
- The source. The water, where it is, and how much it actually gives. Borehole, dam, river, tank, reticulated tap — the water quantity and quality assessment is where every design starts, because the source's dry-season yield is the number the whole system is built on.
- The delivery. How the water gets from the source to the field at the pressure the system needs: gravity (the head — roughly 1 metre of height gives 0.1 bar, so a tank 10 metres above the field gives about 1 bar at the base), a pump, or the two together. This is where the pressure for the next sections comes from.
- The head assembly. The filter (the system's immune system — it keeps the sediment out of the emitters), the valves (the zone controls), the gauges (the pressure readings the design is checked against), and — where you feed through the line — the fertigation injection point. Always after the filter, never before.
- The pipework. The mainline (the trunk — sized for the total flow), the laterals (the branches — sized for each zone's flow), and the regulators where the pressure is higher than the lines can take. The pipe sizes are a hydraulic calculation, not a guess — undersize the mainline and the far end of the field is always a little dry.
- The drip lines. The drip lines or tape with their emitters — the components that actually wet the soil. The emitter spacing (how far apart the emitters are) and the flow (litres per hour each) are set by the crop's spacing and demand. The flush points at the line ends are not an extra — they're how the system stays clean.
Why "even flow" is the whole game
The measure of a drip system is not "does water come out" — it's does the last emitter on the last line flow the same as the first. That evenness is what the crop's uniformity depends on, and it's engineered, not hoped for: the emitter spacing is set from the plant spacing (so every plant sits in the wetted zone), the pipe sizes are set from the flows (so the pressure at the far end is still in range), the pressure-compensating emitters are specified where the field slopes (so the position doesn't change the flow), and the filtration is matched to the source (so the evenness doesn't clog out over the season). A system that's even on install day and uneven by month three is a filtration problem, not an emitter problem — which is why the filtration guide exists as its own document.
Pressure — the number that runs everything
Every component in the system has a pressure range it wants to work in, and the design's job is to keep the water in range at the farthest point:
- The lines and emitters are rated for a working pressure (commonly around 1 bar for standard drip lines; the tape's rating is similar). Too low and the flow drops; too high and the line bursts or the emitter overflows.
- Gravity gives roughly 0.1 bar per metre of head — the tank on the hill is the cheapest pump on the farm, and it's why the source's position is a design question, not a footnote.
- The pump is specified from the flow and the lift — the litres per hour the field needs, plus the metres the water must rise — and the design guide walks the calculation.
- The regulator is where the pressure is higher than the lines want (a high source, a big pump) — it drops the pressure to the lines' range, and it's the component that's missing from a lot of "why do my lines burst" stories.
The schedule — where the water meets the crop
The system delivers; the schedule decides. A drip system's daily run is set from three things: the crop's demand (what the crop drinks, by stage), the emitter flow (what the line puts out per hour), and the soil (how much it holds between runs). Sandy soils want shorter, more frequent runs; heavy soils want longer, less frequent ones. The drip irrigation guide walks the scheduling method, and the automation is what holds the schedule through the busy weeks — because a schedule that varies with the farmer's free time is a schedule the crop can see.
What a working system looks like after a year
A system built with all five links right ages well: the lines are still even (the filtration held), the pump still runs (the service calendar ran), the valves still open (the cycling routine ran), and the as-built document still matches the ground. A system built with the links short — the kit chosen against a budget, the filter skipped, the pump labelled by acreage — shows its shortcuts in the first season, and they compound every season after. The maintenance service and the maintenance guide are the routine that keeps the links right after install day. And when a link does fail, the common problems guide is the diagnosis sequence.
Next, in the guides
FAQ
Basic drip questions
How much pressure does a drip system need?
Most standard drip lines want to work around 1 bar — enough to push the flow through the pipe and out the emitters, not so much that the line bursts or the emitter overflows. Gravity gives roughly 0.1 bar per metre of head, a pump fills the gap where gravity can't, and a regulator drops the pressure where it's too high. The exact number comes from the line's rating and the field's layout — the design guide walks the calculation.
Does drip irrigation use less water than other methods?
Yes — drip can improve water-use efficiency against basin flooding and overhead sprinklers, because the water goes to the root zone instead of the air and the surface: less evaporation, less runoff, and the weed line stays dry. The honest framing is "can improve water-use efficiency" rather than a fixed percentage — the actual saving depends on the soil, the crop, the schedule and the previous method. The drip vs sprinkler guide walks the comparison.
What breaks first in a drip system?
The filter routine, not the filter — the component that fails is the one whose service was skipped. A clogged line is almost always a filtration story (the filtration guide); a burst line is usually a pressure story (the missing regulator); a struggling pump is usually a source story (the dry-running protection, the missing strainer). The common problems guide walks the four failure families and their usual causes.
Can I run fertilizer through the drip system?
Yes — that's fertigation, and it's one of the system's biggest advantages: the feed goes where the roots are, on the same schedule as the water. The setup is the injection point after the filter, the tanks, and the flush line — and the safety rules (never two incompatible feeds at once, always flush after) are in the fertigation guide.
How long does a drip system last?
The durable drip lines are rated for multiple seasons (the UV-stabilised lines take several years of field exposure; the storage matters too — a line kept out of the light lives longer). The tape is single-season by design. The pipes and fittings are the decades-long components. The honest answer: the system's life is set by the weakest link's maintenance — the maintenance guide is the routine that stretches it.
Ready to put it on your farm
Send your layout, crop and water source — the design is the method applied to your numbers.