system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why are water mains buried beneath streets?

It seems like having water mains and other infrastructure under roads creates more work and costs more money when repairs/changes need to be done.  Why not have these structures in a spot that is easier to access, like under the grass between the sidewalks and the road (i.e. terraces)? Are there any advantages to having them under the streets? Any history?
gpt
Engineer for the Highway Dept. here:

Since public utilities are installed to benefit...well...the public, they are installed along the road which is also known as the public right-of-way and owned and maintained by the municipality. Installing these big public water/gas/telecom/electric etc. lines through private property means tons of paperwork, easements, and legal agreements between the utility and who knows how many property owners.

Regarding your specific example of installing them along the "grass strip" yes that is usually also in the public right-of-way and sometimes yes, the lines are installed there. You have to remember though, that the water lines have to share space with all the other stuff in the ground, sewer mains, gas mains, buried fiber optics or electric, storm drainage pipes, there's a ton of shit buried under our roads. Sometimes it just comes down to using whatever little strip of land is left in the ROW for installing the main.