You may be thinking, “What? Two different sizes of ½”? How does that work?” Well, great question! 

Unfortunately, there are no industry standards in drip irrigation tubing!  Many of the manufacturers offer several different sizes of poly tubing especially in the 1/2" family. At Drip Depot, we standardize in a 1/2" tubing with .600" inside diameter and .700" outside diameter. Due to the lack of industry standards buying parts from multiple vendors can be difficult.  If you purchased your tubing elsewhere, do you know the inside diameter of your tubing? This will help you determine the compatibility of our fittings with your tubing!  If you come to the conclusion that your tubing has a different ID and OD than our tubing and fittings, no worries! Here are some great solutions for you! Check out this chart: 

Perma-Loc Series

Nominal Size

Acceptable Inside Tubing Diameter

Acceptable Wall Thickness



.510" to .580"

.035" to .055"



.590" to .630"

.025" to .050"



.790" to .845"

.045" to .065"



1.025" to 1.085"

.045" to .070"

If your tubing is smaller than .590” to .630” ID, then you may be able to use the ⅜”  500 Series Perma-loc fittings instead of the ½” 600 Series Perma-loc fittings! Unfortunately, our Perma-loc fitting selection in the ⅜” 500 Series size is limited. If the fitting type that you need is not available in ⅜” size and your tubing has an OD of .630” to .710” then you will be able to use Drip-Lock Fittings

Here are item links you may need: 


Perma-loc Fittings

Poly Tubing

Here are article links you may find helpful:

Selecting the Correct Fitting

Fitting Installation Tips

Fitting Buying Guide



Still have questions? No problem! Please feel free to reach out to our wonderful and knowledgeable Customer Service Team!