Parts of a Drip Irrigation System

All 10 parts on the diagram

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At the faucet 4

Timer (controller) Opens the water for a set time. A mechanical or battery-powered timer sits on the faucet. Larger systems use a controller and electric valves.
Backflow preventer Stops water being sucked back from the garden into the household supply. Small ones screw straight onto an outside faucet.
Filter Its screen catches particles large enough to clog the emitters. It is cleaned out from time to time.
Pressure regulator A drip system runs at low pressure. The regulator reduces the pressure of the household supply before the water reaches the tubing.

In the garden 6

Mainline Soft polyethylene tubing, laid on the ground, not buried. Emitters and smaller tubes are plugged into it.
Fittings Tees, elbows, connectors and end caps are all fittings. They come in compression, barbed and locking types.
Emitters (drippers) Each controls how fast water is released. The water goes to the soil at the roots of a plant. They are sold by flow rate.
Drip line (emitter tubing) The emitters are set inside the tubing at even spacings. One line then waters a whole row.
Micro-spray A low-pressure sprayer, usually on a stake. It wets the soil with a jet or fan of water, not drips.
End cap It closes the end of a line. The water is then forced out through the emitters.

How this list was compiled: Every name checked on 2026-09-30 and kept only where two independent sources use it: a state university extension fact sheet on drip irrigation for home gardens (https://extension.colostate.edu/topic-areas/yard-garden/drip-irrigation-home-gardens-4-702/), Wikipedia, Drip irrigation (text only), and two more extension publications (https://extension.psu.edu/drip-irrigation-for-vegetable-production and https://extension.usu.edu/yardandgarden/research/designing-a-basic-pvc-home-garden-drip-irrigation-system). Licence: own work

The drawing: Drawn for this site on 2026-09-30 from plain geometry; no maker's product, nothing traced. Licence: own work

How it works

A garden drip irrigation system fed from an outside faucet, in two drawings. The numbers follow the water: first the parts screwed onto the faucet, then the tubing laid through the garden.

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The head assembly, in order

Four parts go between the faucet and the tubing. A timer turns the water on and off. A backflow preventer keeps garden water out of the household supply. A filter catches grit that would clog the emitters. A pressure regulator then lowers the pressure, because drip tubing runs at low pressure.

In the garden

The mainline carries water past the plants, joined by fittings such as tees and elbows. Emitters plugged into it drip water at single plants. A drip line, with emitters built in, waters a row. A micro-spray wets a small area, and an end cap closes the tube.

Keep the order at the faucet: backflow preventer, then filter, then pressure regulator.
Two common mistakes are leaving out the filter or the pressure regulator.

Questions and answers

What are the parts of a drip irrigation system?

At the faucet: a timer, a backflow preventer, a filter and a pressure regulator. In the garden: mainline tubing, fittings, emitters, drip line with built-in emitters, micro-sprays and end caps.

What order do drip irrigation parts go in?

At a faucet: timer, backflow preventer, filter, pressure regulator, then the tubing. In a permanent system the order is backflow preventer, control valve, filter, pressure regulator.

Does a drip irrigation system need a pressure regulator?

Yes. Drip irrigation applies water slowly under low pressure, so a pressure regulator goes at the head of the system to reduce the pressure of the supply. Leaving it out is a common setup mistake.

What is the difference between an emitter and a drip line?

An emitter is a single device plugged into the tubing to water one plant. A drip line is tubing with emitters built in at even spacings, used to water a row.