J,

You are looking at the problem from the wrong direction. underground drip lines will clog and your lawn will look spotty because water is not evenly distributed. Then you have to dig up the lawn to replace bad areas. That is why nobody does this. If the area is small. Do a perimeter line that sprays from the side onto the lawn area with popups. Why do drip for a lawn? It is way more expensive anyway. Does this make sense to you? Aloha JMHO

Hi Lehua,

quite true, underground dripline is more expensive, but mind you, around here it's the PE fittings pushing the price up. Anyway, proper underground dripline should function quite alright, even without feeding it contact herbicide.
I started off with the dripline because we always have something on the turf that I'd rather not get wet - and that I'm sure I'd forget before starting the water.. Beyond that it gets academic; precisely because the lawn is small, the price is also not that high, and I do have regular dripline feeding the flower beds and the fruit trees - so I was keen to see if underground would fare well. It was the pressure issued - combined with a much higher application rate - which made me think twice and ask here :)