Which Dripline Do I Need?
UK Flow Centre buying guide
Choose a dripline system in five simple steps
Start with where the pipe will sit, then choose a suitable line or kit. This guide gives you genuine options rather than pushing one brand: Rain Bird for purpose-specific above- or below-ground lines, and Netafim UniTechline AS where you want a flexible surface-or-subsurface choice.
1. Where will the dripline sit?
The simple rule
Do not bury ordinary above-ground dripline. If the system is going underground, choose a line specifically intended for subsurface use, then use the matching fittings and suitable filtration.
2. Want most of the parts together? Start with a kit
For a new garden system, a kit can be the easier route. It gives you a sensible starting layout; add extra pipe, fittings or zones as your project grows.
3. Pick the emitter spacing and layout
Emitter spacing and row spacing are different. Emitter spacing is the fixed distance between outlets along the dripline. Row spacing is the distance between parallel runs that you choose when laying out a bed or planted area.
| Decision | What it changes | Practical check |
|---|---|---|
| Emitter spacing | How many outlets are present per metre and therefore the zone flow. | Closer spacing can suit dense planting or lighter, free-draining soil; wider spacing can suit individual shrubs or heavier soil. |
| Row spacing | How the wetting patterns from neighbouring laterals overlap across the bed. | Base it on soil, planting and the manufacturer’s layout guidance rather than emitter spacing alone. |
| Run length and slope | Pressure loss and how evenly the emitters can operate along each lateral. | Check the exact product’s maximum lateral table for its flow, spacing, inlet pressure and elevation change. |
Useful field check: before committing to a permanent buried layout, run a representative section, allow the soil to wet, then inspect how far the moisture spreads sideways and down. Dry strips between runs mean the row layout needs correcting; more run time does not fix poor overlap.
4. Build the system around the dripline
A reliable dripline layout normally needs more than the pipe itself:
- Filter: protects emitters from grit and debris. Shop filtration.
- Pressure regulation: keeps the selected line within its specified working range.
- Supply header: distributes water to the individual dripline laterals without asking one long lateral to feed the entire area.
- Accessible flushing route: lets debris leave the ends of the laterals or a flush header during commissioning and maintenance.
- Air/vacuum protection where required: subsurface layouts may need an air/vacuum relief valve at the high point or on a connected header, following the exact manufacturer design.
- Compatible fittings: start connectors, tees, elbows, couplers and end closures. Shop dripline and fittings.
- Timer or control valve: makes regular watering simple and repeatable.
Pipe sizes are often described as 16 mm or 17 mm, but fittings are not automatically interchangeable between brands. Match the fittings to the exact dripline you select, especially on Rain Bird XF and Netafim systems.
Draw the water route before ordering
Valve or timer, filter and pressure regulator selected for the total zone flow.
A header carries water to the start of each correctly sized lateral.
Parallel or shaped laterals follow the manufacturer’s run-length and spacing limits.
Every route finishes at an accessible flush point or correctly designed flush header.
Why this matters: the total installed length sets the zone demand, while the length of each individual lateral affects pressure loss and uniformity.
Compare actual flow options before ordering
Emitter flow is the water from each outlet, not the whole coil. At the same spacing, a 2.3 L/h line uses more water per hour than a 1.6 L/h line. Choose around soil wetting, planting needs, available supply and run time, not simply the larger number.
- Surface, lower emitter flow: Rain Bird XFD, 1.6 L/h, 33 cm spacing, 100 m coil.
- Surface, higher emitter flow: Rain Bird XFD, 2.3 L/h, 33 cm spacing, 100 m coil.
- Subsurface example: Rain Bird XFS, 1.6 L/h, 33 cm spacing, 100 m coil. Burial depth, row spacing, air/vacuum protection and flushing must follow the design for the site.
How much water will the zone need?
Approximate zone flow = total installed dripline length ÷ emitter spacing × emitter flow. Use metres for both length and spacing. For 100 m at 0.33 m spacing, the estimate is about 485 L/h (8.1 L/min) at 1.6 L/h, or 697 L/h (11.6 L/min) at 2.3 L/h. Add every branch running at the same time. Actual emitter count and any separate outlets affect the total.
A 100 m coil is a purchase length, not permission for a 100 m single run. Check the manufacturer's maximum lateral length for the exact flow, spacing, inlet pressure and slope. A 200 m kit does not mean 200 m can be laid as one continuous lateral. Pressure compensation cannot overcome an inadequate water supply.
Fittings for the Rain Bird XF examples
For joining or repairing compatible XF tubing, use the Rain Bird XF barbed coupler, bag of 25; for a branch, use the Rain Bird XF barbed tee, bag of 25. Rain Bird specifies XF insert fittings for XFD. These fittings are sold as 17 mm XF fittings even where the dripline option is described as 16 mm. That is a named-system match, not a rule that all 16 mm and 17 mm products fit each other. Do not assume these fittings suit Netafim or plain MDPE.
Next, choose filtration and pressure control. Include accessible flushing ends and check whether the selected kit already contains a filter or regulator before adding more parts.
Manufacturer guidance: Rain Bird XFD operating and fitting guidance, XF Series design, installation and maintenance guide and Rain Bird air/vacuum relief guidance. Regional flow options differ; use the selected UK product and its matching design data.
Keep a record of the zone you are choosing
Send these details when asking for help:
- A sketch of laterals, total length, longest run and changes in level.
- Exact line, emitter flow and spacing, soil and planting.
- Source and measured flow with working pressure at the same supply point.
- Branches operating together and filter/regulator identities.
- Flushing points and maintenance access.
Rain Bird’s XF design guide, “Preparation for Design”, uses source and layout information of this kind. Match its product tables to the selected line and regional specification; they are not interchangeable limits for other brands.
5. Quick choice by project
- Patio pots, a small veg bed or individual plants: choose a starter kit or micro-irrigation approach.
- New borders and long hedges where the pipe can remain visible: Rain Bird XFD or a surface installation using Netafim UniTechline AS.
- Permanent planting or a hidden layout: Rain Bird XFS, or Netafim UniTechline AS where a surface-or-subsurface option suits the design.
- Large or multi-zone project: begin with the water source, filtration and pressure plan, then choose the line, fittings and controls.
Still unsure?
Send our team a photo, the approximate lengths and whether the pipe will be above or below ground. We can help you identify compatible components before you order.
Quick dripline questions
Are 16 mm and 17 mm dripline fittings interchangeable?
Not automatically. Match every connector, tee, elbow, coupler and end closure to the exact dripline system you select.
Can surface dripline be buried?
Use a dripline specifically designed for subsurface installation and follow its filtration and flushing requirements. Do not bury an ordinary surface-only line.
What should I check before choosing a dripline?
Start with surface or subsurface installation, the area and lateral run lengths, planting, emitter spacing and row spacing. Then check the measured water supply, total zone flow, filtration, pressure regulation, compatible fittings, flushing route and controls.
Does every dripline zone need an air relief valve?
Not automatically. For a subsurface layout, check the exact manufacturer’s air/vacuum-relief requirement and location. Its job is to release trapped air while filling and admit air while draining, reducing vacuum suction through buried emitters. It does not replace filtration, pressure regulation or flushing.
Shop dripline, fittings and kits Troubleshoot uneven watering
Technical guidance from UK Flow Centre, operated by JK Irrigation Ltd. Explore all guides in the Technical Hub.
Feeding dripline from collected rainwater
Check the dripline’s required pressure and flow. A water butt with a gravity outlet is not automatically suitable for pressure-regulated dripline. Plan compatible pumping, filtration and controls around the tank and water quality.
Read the water butt and rainwater harvesting guide | Shop water butts for collection in Sevenoaks
