Check the tubing size against the fitting, then the pressure regulator. “1/2 inch” tubing is sold in several real sizes, and the outside diameter decides which compression fitting to use. A regulator protects the system from pressure surges blowing out the fittings.
Check these in order
The fitting doesn’t match the tubing
How to tell: Read the size printed on the tubing (for example .700 OD) and on the fitting package. DIG makes separate compression fittings for .620", .700" and .710" tubing.
Fix: Use fittings made for your tubing’s outside diameter, or universal nut-lock fittings that fit the common half-inch sizes. See drip tubing sizes or measure it.
No pressure regulator, or a faulty one
How to tell: Fittings blow off or emitters pop out when the water comes on. Put a pressure gauge at the end of the line; above 25 psi, the regulator may be faulty.
Fix: Fit a drip pressure regulator after the filter; DIG’s and Rain Bird’s faucet regulators are set to 25 psi. See connecting drip to a faucet.
Hose thread mixed with pipe thread at the faucet
How to tell: The leak is at the faucet end, where the backflow preventer, filter and regulator screw together.
Fix: Make every joint hose thread to hose thread, or use a hose-to-pipe adapter. Mixing them will cause leaks, and Teflon tape won’t fix it.
Emitters popping out of the tubing
How to tell: Individual drippers come loose rather than fittings.
Fix: A wrong or worn punch tool can make the holes badly; use a new punch the right size for the emitters. Check the pressure as in step 2.