Guide · Drip line
Drip line spacing and maximum run length: read the maker's table
Why a drip line coil is not a run length, DIG Microline's 16-28 ft limits on 1/4 in line, Rain Bird XFD's table, and how to read a maker's run table.
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Picks that fit
- DIG Microline SHB106 1/4 in dripline (6 in spacing, 100 ft, brown)Check price on Amazon
- DIG Microline ML‑112 1/4 in dripline (12 in spacing, 100 ft, black)Check price on Amazon
- DIG Microline SH512 1/4 in dripline (12 in spacing, 500 ft, black)Check price on Amazon
Short answer
A coil's length is not a run length. Each maker publishes a maximum single run for its own drip line, by emitter spacing, flow and inlet pressure. On DIG's 1/4 in Microline it is only 16 to 28 ft at 25 psi, while Rain Bird's 1/2 in class XFD runs hundreds of feet. Find your exact model in its maker's table, and do not extrapolate.
Picks that fitAll picks and how to choose
Why a run has a limit
A lateral is one run of drip line from its feed point to its end. Water loses pressure as it travels along it, and every emitter on the way takes some flow. So the emitters at the far end of a long run get less than those near the start.
A Utah State University Extension drip design presentation illustrates this: pressure loss along 1/4 in tubing lowers emitter discharge farther from the manifold more than along 1/2 in tubing.[1] That is why 1/4 in line has short limits and 1/2 in class line has long ones. The maximum lateral length is the maker's answer to how far one run can go before that loss is too much.
1/4 in drip line
DIG's Microline is 1/4 in dripline, .170 in ID by .250 in OD, with emitters every 6, 9 or 12 inches.[2] DIG rates it for 10 to 25 PSI with a nominal 0.52 GPH per emitter at 15 PSI.[2] DIG's table shows the flow rising with pressure, from 0.42 GPH at 10 psi to 0.65 GPH at 25 psi.[2]
DIG lists the maximum single run at 25 psi on flat ground as 16 ft at 6 inch spacing, 22 ft at 9 inch and 28 ft at 12 inch, even though Microline coils run from 100 to 3,000 ft.[2] DIG's homeowner page gives the same limits and notes they are based on 0% slope.[3]
| DIG Microline spacing | Maximum single run at 25 psi, level ground |
|---|---|
| 6 in | About 16 ft |
| 9 in | About 22 ft |
| 12 in | About 28 ft |
Rain Bird's 1/4 in Landscape Dripline comes in 100 ft coils with 6 or 12 inch spacing, at 0.8 GPH at 30 psi, rated for 10 to 40 psi.[4] Its page gives no maximum run, so we have none to report for it.
1/2 in class drip line
Rain Bird lists XFD in 0.6 and 0.9 GPH flows at 12 or 18 inch spacing, for 8.5 to 60 psi.[5] Its lateral table allows longer runs at higher inlet pressure. For 0.6 GPH emitters at 12 inch spacing, it gives 273 ft at 15 psi and 460 ft at 60 psi.[6] For 0.9 GPH at 12 inch spacing, it gives 155 ft at 15 psi and 290 ft at 60 psi.[6]
Rain Bird sells XFD in 100, 250 and 500 ft coils, listed separately from that table.[7] As with Microline, the coil is what you buy, not what one run can be.
Netafim lists Techline CV at 0.26, 0.4, 0.6 and 0.9 GPH with 12, 18 or 24 inch spacing; 24 inch spacing comes only with 0.6 and 0.9 GPH.[8] We did not read a Techline CV run table, so we quote no length for it.
| Line | Spacing | Flow | Run figure we could source |
|---|---|---|---|
| DIG Microline, 1/4 in | 6, 9, 12 in | 0.52 GPH at 15 PSI | 16, 22, 28 ft at 25 psi |
| Rain Bird 1/4 in Landscape Dripline | 6, 12 in | 0.8 GPH at 30 psi | None published on its page |
| Rain Bird XFD | 12, 18 in | 0.6 or 0.9 GPH | 155 to 460 ft, by flow and pressure (12 in examples) |
| Netafim Techline CV | 12, 18, 24 in | 0.26 to 0.9 GPH | Not read |
Does spacing change run length?
Yes. Closer emitter spacing means more emitters per foot, so more flow leaves the line early. DIG's table shows it plainly: 16 ft at 6 inch spacing against 28 ft at 12 inch.[2] Flow matters the same way. On XFD at 12 inch spacing, the 0.9 GPH line's limits are shorter than the 0.6 GPH line's.[6]
How to read a maker's table
- Find your exact model. A table for XFD says nothing about another brand's 1/2 in line, or about Microline.
- Find your spacing and emitter flow.
- Find your inlet pressure: the pressure where the run starts, after any regulator.
- Read the length. If your numbers fall between rows, use the shorter figure.
- Do not extrapolate beyond the table, and note the slope it assumes. DIG's limits are for level ground.[3]
If a run needs to be longer, split it into several shorter runs fed from a 1/2 in supply line.
Drip line that fits this decision
Picks that fit10 products
For short 1/4 in runs, choose DIG Microline SHB106 (6 in spacing, 100 ft coil, about 16 ft per run at 25 psi per DIG), DIG Microline ML-112 or SH512 (12 in spacing, 100 or 500 ft coil, about 28 ft per run at 25 psi per DIG), Rain Bird ET256-50S (6 in spacing, 50 ft) or ET25-50S2 (12 in spacing, 50 ft, also sold with Rain Bird's FCKIT faucet kit).
More on choosing
For long runs, choose Rain Bird XFD-09-12-100 (0.9 GPH, 12 in spacing) or DIG B18250 (.700 in OD, 1 GPH PC, 18 in spacing, 250 ft; DIG lists up to 273 ft per lateral at 25 psi on level ground). Orbit 67376 is .700 in tubing with 1 GPH PC emitters every 12 in, 100 ft; Orbit publishes no maximum run. DripWorks DET121 is 0.600 x 0.700 in with 1 GPH PC emitters every 12 in, 500 ft; DripWorks gives a 250 ft maximum single run at 10 to 50 psi.
1/4 in line for short runs in beds
DIG Microline SHB106 1/4 in dripline (6 in spacing, 100 ft, brown)
1/4 in line with wider spacing
DIG Microline ML‑112 1/4 in dripline (12 in spacing, 100 ft, black)
1/4 in line in a 500 ft coil
DIG Microline SH512 1/4 in dripline (12 in spacing, 500 ft, black)
Rain Bird ET256‑50S 1/4 in emitter tubing (0.8 GPH, 6 in spacing, 50 ft)
Rain Bird ET25‑50S2 1/4 in emitter tubing (0.8 GPH, 12 in spacing, 50 ft)
Rain Bird ET25‑50S2 1/4 in emitter tubing (0.8 GPH, 12 in, 50 ft) with FCKIT faucet connection kit
1/2 in class line for long rows
Rain Bird XFD‑09‑12‑100 on-surface dripline (0.9 GPH, 12 in spacing, 100 ft)
.700 OD line for long rows
DIG B18250 Earthline Brown PC 1/2 in dripline (1 GPH, 18 in spacing, 250 ft)
.700 line with 12 in spacing
Orbit 67376 1/2 in (.700) pressure-compensating drip emitter tubing (1 GPH, 12 in spacing, 100 ft)
.700 line with 12 in spacing and a stated range
On Amazon, check that "Ships from" and "Sold by" show Amazon.com or the brand before you order.[9]
Next
Questions
How long can a drip line run?
As long as its maker's table allows for your spacing, flow and inlet pressure. Rain Bird's XFD table gives 273 ft at 15 psi and 460 ft at 60 psi for 0.6 GPH at 12 inch spacing.[6]
How long can 1/4 inch drip line be?
For DIG Microline, about 16 ft at 6 inch spacing, 22 ft at 9 inch and 28 ft at 12 inch, at 25 psi on level ground. Other 1/4 in lines need their own maker's figure.[2]
Does emitter spacing change run length?
Yes. Closer spacing puts more emitters on each foot, so DIG's Microline limit drops from 28 ft at 12 inch spacing to 16 ft at 6 inch.[2]
Can I use a whole 100 ft roll of 1/4 in drip line as one run?
Not per DIG's table for Microline, which tops out at about 28 ft per run at 25 psi. Cut the coil into several runs fed from a 1/2 in supply line.[2]