Using 4 steel radiator like bands, I replaced a section of underground lawn sprinkler black plastic pipe that runs over a septic drain field.    Repair couplers do not leak until i press my foot down on one of four running sprinkler heads.  Is that normal?  [Would the leak have been due to the hair dryer i used to make the plastic pipe more pliable?](https://diy.stackexchange.com/questions/66559/is-it-ok-to-use-a-hair-dryer-on-underground-lawn-sprinkler-pipe)

Hoping someone has tried the same stress test and would share their experience.  I understand the physics of increasing the pressure by closing off an end.   Hoping to get the perspective of lawn sprinkler experts as to whether these radiator hose couplings almost always leak a little when pressurized?  I want to keep unnecessary water from getting into the septic drain field.  


Water pressure where I live is 85psi, but noticed most water garden hose accessories sold locally are rated to only 60psi.


  [1]: https://diy.stackexchange.com/questions/66559/is-it-ok-to-use-a-hair-dryer-on-underground-lawn-sprinkler-pipe