Thanks for all the help and info, guys.

I think I can use anti-siphon valves to handle backflow, in my residential application. Have to confirm. They are not expensive in PVC. But the last sprinkler system I installed, I used all-brass anti-siphon valves and I'd like to do that again. I can find only two brands of all-brass anti-siphon valve for residential applications, Champion and Orbit. (Anyone have experience with either?)

As for sod vs seed, I need shade tolerant grass, which might limit my sod choices. I'll check around.

Bill, the side yard will be the garden spot. Stone or brick path, maybe a little patio with a cafe table, surrounded by flowers, ferns, and plants. Tall foilage to conceal or soften the HVAC enclosure, sprinkler manifold, etc and give the cats a jungle where they can stalk the chickens.

i wanted to chime in.

for that tiny patch of yard, you can cover it up with black plastic (visqueen). the heat will destroy the old grass down to the roots. then you can till it with some good soil amendments. hopefully you wont have too much material and need to wheel barrel it out.

i vote sod. i love the insta lawn affect.

Sod farmers do not farm sod in the shade. It is all sod for full sun that can tolerate shade. This is not as good as seed made for shade. I have a Norwegian Maple under which I have sodded twice with shade tolerant sod. Landscapers have always said seed is best but most people can not wait for seed to grow. The instant lawn is fun to see it instantly installed.

Sounds like my lawn except you forgot to say it as dark as under the canopy of a rain forest. Add tree roots and you have very sparse grass.