Guide · Mainline tubing
What size is your 1/2 in drip tubing? .620, .700 and .710 OD
"1/2 in" drip tubing comes in at least three outside diameters. The ID x OD pairs each maker lists, and how to find yours before you buy fittings.
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Short answer
"1/2 in" drip tubing is sold in at least three outside diameters: about .620-.630 in, .700 in and .710 in. Fittings are made for an OD range, so find your tubing's OD (printed on the tube, in the kit's documentation, or measured) before you buy a single fitting.
Why one name covers three tubes
"1/2 in" is a nominal size, a family name rather than a dimension. One maker shows the problem clearly: Rain Bird sells its 1/2 in blank distribution tubing in three series, T63 at 0.63 in OD, T70 at 0.70 in OD and T71 at 0.71 in OD.[1] Rain Bird's own store lists the T63 at 0.63 in OD with a 70 psi rating.[2]
A tenth of an inch sounds small, but fittings grip the tube by its outside or inside. A fitting made for .700 in tubing is not listed for .710 in tubing, and the reverse is also true. That is why this site sorts tubing by OD, not by brand or by the "1/2 in" on the bag.
The sizes makers actually list
Each row is the inside diameter (ID) by outside diameter (OD), exactly as the maker states it.
| Maker and product | ID x OD (in) | Source |
|---|---|---|
| DIG 1/2 in poly tubing (B35, B36, B39, B37, B43) | .600 x .700 | DIG[3] |
| DIG .710 tubing (TS100, TS500) | .620 x .710 | DIG[4] |
| Raindrip 062010P supply tubing, 100 ft | .620 x .710 | Raindrip[5] |
| A .520 x .620 tubing size Raindrip lists for Smart Loc | .520 x .620 | Raindrip[6] |
| Mister Landscaper MLT-71 (50 ft) and MLT-72 (100 ft) | .600 x .700 | Mister Landscaper[7] |
| Tubing in DIG's ML50 kit (50 ft) | .600 x .700 | DIG[8] |
| B35 tubing in DIG's G77AS kit | .600 x .700 | DIG[9] |
| Rain Bird T63 / T70 / T71 | OD only: 0.63 / 0.70 / 0.71 | Rain Bird[1] |
Rain Bird's product page gives no ID for its three series, so we leave the ID blank rather than guess.
A fitting that states its range
Raindrip's Smart Loc S5600UB coupling is a good example of how a fitting should be labeled. Raindrip lists three tubing sizes for it: .520 x .620, .600 x .700 and .620 x .710 in.[6] When a fitting names the pairs like this, you can check your tubing against it in seconds.
Fittings that only say "1/2 in" leave you guessing. Our guide to what "universal" means on drip fittings compares the stated ranges of the common range-based fittings.
Numbers not to trust
Two maker figures conflict with the maker's own data, so do not choose a fitting by them:
- Wall thickness on DIG's tubing pages. DIG's .710 page prints a wall figure that does not match its own .620 x .710 pair, and the .700 page has the same problem.[4] Use the ID and OD, not the wall figure.
- Raindrip's FAQ figure. Raindrip's FAQ says its 1/2 in fittings work with tubing that has an I.D. of .620-.630 in, while Raindrip's product pages use .620 as an OD for some tubing.[10] Use the ID x OD pair on the product page instead.
If the numbers on your tubing and the fitting still disagree, ask the fitting's maker before you buy.
Tubing whose maker states the OD
If you are starting fresh or extending a line, buy tubing whose maker states its OD, then buy fittings for that OD.
Picks that fit5 products
Choose by OD: Rain Bird T63-100 is 0.63 in OD and T70-100S is 0.70 in OD, both 100 ft coils; Drip Depot's 100 ft coil and DripWorks' 50 ft coil are .600 x .700 in; Raindrip 062010P is .620 x .710 in, 100 ft.
More on choosing
Match the OD to the tubing you already have.
For tubing at about .620-.630 in OD
Rain Bird T63‑100 1/2 in blank distribution tubing (0.63 in OD, 100 ft)
For tubing at .700 in OD
Rain Bird T70‑100S 1/2 in heavy-duty blank distribution tubing (0.70 in OD, 100 ft)
For .700 in OD tubing, ID stated
Drip Depot 1/2 in polyethylene tubing (0.600 x 0.700 in, 100 ft)
For .700 in OD tubing, pressure and fittings stated
DripWorks 1/2 in polyethylene mainline tubing (0.600 x 0.700 in, 50 ft)
For tubing at .710 in OD
Raindrip 062010P 0.710 in supply tubing (0.620 x 0.710 in, 100 ft)
On Amazon, check that "Ships from / Sold by" is Amazon.com or the brand before you buy.[11]
Next
Questions
What size is 1/2 inch drip tubing?
There is no single size. Makers list 1/2 in tubing at about .620-.630, .700 and .710 in outside diameter; Rain Bird alone sells T63, T70 and T71 at 0.63, 0.70 and 0.71 in OD.[1]
Is 1/2 inch drip tubing measured on the inside or the outside?
Neither exactly. "1/2 in" is a name, not a dimension. DIG's 1/2 in tubing is .600 in ID by .700 in OD, and Raindrip's 062010P is .620 in ID by .710 in OD.[3][5]
Are .700 and .710 drip tubing interchangeable?
Not for every fitting. DIG sells separate compression fittings for .700 and .710 in OD, and a reducing coupling to join them. Use a fitting whose maker lists your OD; see joining .700 tubing to .620 or .710.[14]
What tubing came in my drip kit?
Check the kit's own documentation. For example, DIG's ML50 kit instructions list 50 ft of 1/2 in tubing at .600 in ID by .700 in OD.[8]
Can I use Raindrip's FAQ figure to choose a fitting?
No. Raindrip's FAQ gives .620-.630 in as an I.D. for its 1/2 in fittings, while its own product pages use .620 as an OD, so the figure conflicts with Raindrip's product data.[10]