I had a leak on the original galvanized line 2 weeks ago, and upon digging it up, found the whole line (not surprisingly) was in terrible shape. I've since had a guy dig up the old line for me, so I just need to put the new line in. I was originally going to run the new line as PEX. When I told my neighbor this, he said that he sells PEX and his technical guys recommend putting it in conduit and not direct burying it. Research online seems to indicate that would be necessary in areas with acidic soil, but I'm not sure that's an issue here in Houston. I think a better argument could be made just to protect it from unintentional damage should someone dig around some point in the future.

The previous owner replaced the last 3' into the house with PVC, so I'm thinking it might be easier to just replace the rest of the line with PVC vs. using PEX and burying the transition from PEX to PVC in a random spot in the yard.

Is there any benefit for using PEX vs. PVC in this application that would justify the extra cost of the conduit and the minor headache of running it in conduit?

Some pics for your viewing pleasure. The new galvanized section is the repair I made from the leak 2 weeks ago. The T just down from the meter box is where I assume the irrigation system T's off. The 90* is where it transitions to PVC just before going into the house.

Just use CPVC and avoid the headache.

I have fixed many broken pvc water mains over the past 25 years around BCS. Usually happens during the summer in clay soils but have done a few in Jan/feb when it was really raining often. To me it comes down to how long of run. A short main i would be more inclined to just do pvc.

What are you bedding the plastic lines with? Do you have something other than the black dirt shown in your pics? Go old school and run type K copper tubing. If you have lots of money to throw around that is.

My vote

Schedule 40 PVC

+1/4" for better supply if not +1/2" (3/4" meter does not change, else higher rates charged/gallon in our town)
surplus boards on top
compacted select fill supporting pipe
excess black/clay soils elsewhere, perhaps a garden bed perimeter additive

So I ended up going with 3/4" SCH 40. In a perfect world I would go get 1/2 CY of bank sand to bed the pipe, but with it getting dark at 5pm, I don't have time to go and get the sand and get it in the hole before the guy comes back to backfill the trench. This isn't our forever home, so as long as it holds for 10 years, it'll be fine.

I put a new ground box in to replace the one that had been destroyed, including putting gravel down so it's not constantly full of mud. Will add some pics with the next post.

Thanks to all for the input!