It depends on everything (water pressure, how hard you turn the water on, hose quality).

Put a pet food can under the soaker and see how long it takes to fill up.

While I admire the thought of water conservation, using a soaker hose to water a lawn is like peeing on a house fire so to speak in a lot of cases. Soakers are great for really small areas like a narrow strip between the curb and sidewalk. But to water a lawn in most cases is not possible even leaving it on 24 x 7. By the time you covered the whole lawn the area where you started from would be a desert if your lawn is of any size.

Hey weed, how do they use drip irrigation in fields? That might be a better alternative. We're running across entire sections of land that have drip for cotton and corn. Sort of makes it expensive to build a pipeline through the middle.

Dave the way I seen it done around here, not many here though, is very similar to the way I do it in the garden. Mind you I do not do it commercially. They plant in traditional row plantings and run a hose type pipe down each row with a 1 GPH emitter placed at the base of the plant. Then they use the well water and pump with a special filter to remove any particles and a low pressure regulator. Other than the filter and regulators it looks pretty easy to setup. But mostly around here it is traditional gate or circle irrigation.

duajones,

I use soaker hose for the strip area between sidewalk and street. I barely turn it on and basically leave it there all night long. Works pretty good. I often do it every 2-3 weeks.

Another thing that factors in to how well it will work and over how large of an area is what kind of soil you have. I have a pretty heavy clay. So, it will often get full on top and flow on to adjacent areas and water a wider swath. Of course, I don't think I could use soaker hoses alone for primary use. I use it to hit dry spots in the sprinkler system and to deep water occasionally.

As always, all gardening is ultimately local.