Why are you not keeping the drainage at the surface where it doesn't result in clogged pipes or additional maintenance?

It would block the pathway on the side of the house and also not look good. There's only maybe 6' between the side of the house and the end of the property

"... not look good." Downspouts with tail pieces & splash blocks are the de facto standard for handling water coming from the roof. Once landscaping is in place, they are more or less barely visible or completely unseen.

"It would block the pathway..." You'll need to include a picture that shows the area and explains how this would be. (No close-ups.) I'm not sure what would block a pathway, or how.

The home inspector said that the downspout water should be led 10' from the property, and splashblocks don't accomplish that (splashblocks are already installed). I was assuming you were talking about leading an above-ground pipe from the downspout to 10+' from the property, which would block the pathway. I agree that splash blocks wouldn't block the pathway.

But the manner of leading the water 10' away is not by a single device. The downspout tailpiece leads to the splash block. The splash block carries the water 20-something inches from the foundation wall to the ground surface. The ground surface is sloped down from the house to some 10' away (which is an ideal but often not possible) to where the water finds a route to leave the property. This system works in all but the most peculiar.

No corrugated because that's how you get clogs. Straight PVC. The freezing temperatures aren't a problem.

^^ Agreed on the last TWO posts. You may not need such a pipe, but if you do decide to install it, don't bother with corrugated, it crushes even under just a few inches of soil. My neighbor just dug one up that was not more than 4-6" down, 25 years old or so, and it was crushed to the point of being totally shut off.

Thank you for the comments!

Yardvaark--one downspout exhibits the characteristics you mention--the land around it slopes away from the house, but another downspout doesn't, so I'll most likely do some type of drainage system for a little more peace of mind.

Sounds like PVC is the way to go for the drainage system--thanks again

I second the no corrugated pipe. We had to cut off all of our downspout/corrugated pipe drainage because after 25 years the roots of foundation and yard plantings had invaded the piping thru the connection areas and blocked the drainage.

+1 for pvc. Sch 40 is overkill, 4" pvc sewer & drain pipe has a crush resistance of around 3300 lbs I think. Clogs are unlikely to be an issue, but if you're concerned you can put in a tee with a threaded cap for a cleanout. We do those on long runs, or where there are a lot of turns or connections. The corrugated stuff is garbage, for sure.

@Revolutionary Gardens Where is the best place to buy sewer & drain pipe? I looked at home depot/lowes websites and there isn't much selection

I'd try a commercial plumbing supply co. Although I guess it's possible they don't do S&D pipe, just sch 40. I'll ask my brother as he's up in RI

Home Depot carries white landscape drain pipe that is lighter weight than the schedule 40 used for DWV in house. This is the type I have used https://www.homedepot.com/p/4-in-x-10-ft-Triplewall-Pipe-Solid-4550010/100135310.  Pipe is thinner and fittings are slightly different size than schedule 40, so make sure you get the right fittings when you add the L bend to connect to the downspout. This pipe can be cut and glued like regular PVC pipe.

Bruce

"... the land around it slopes away from the house, but another downspout doesn't ..." And there is no grading you can do to fix it? If not, you could suffer problems even if you go through the bother of dealing with the downspout itself.

I could probably fix it a little? My property ends only around 6'-ish away from the house, so I don't think there's much to play with. I'm not living there right now, but will be in a week--but I realized I could screenshot google maps and then draw on that. "Downspout Location 2" is the one in the backyard, which doesn't have much grading compared to the front yard, which is where "downspout location 1" is

IF you can fix drainage to work above grade, it is less trouble for you in the long run. The idea of running a drainage pipe underground depends on a lower elevation location to let the water out of the pipe. This can be troublesome if there is not much grade differential to work with. Running the pipe underground requires more grade differential because your starting point -- in the ground -- is lower than the starting point at the ground surface. If the pitch of the pipe is not enough, it will not be self cleaning. Some people think that you can run the pipe at a downhill pitch and let the water exit where it must rise up up to the ground surface. (A device called a pop-up relies on this.) This works when new. While clean water will rise up to exit the pipe, silt does not. Eventually it begins to accumulate and over time builds up and eventually the pipe clogs. If it were possible to keep a perfectly clean system it would work, but that's very difficult to do. Gutters get junk in them.

Without knowing the exact particulars, since there are so many variables, it's hard to advise on the best solution. But I would exhaust the above-grade possibilities before considering the below-grade ones. Maybe when you get to the property, you could take better pictures of the problem downspout area and we could pick it back up again. (No close-up pictures, please. The surrounding area needs to be seen.)

It would be good to clarify exactly how much fall you have. You said you could only dig about 6" deep. That's not deep enough for a 25' run. In doing the calculation, you must deduct the starting depth of the pipe from the outfall. Consider that you would want a pipe in the ground to be covered completely with soil, and not be running at, or just under the surface. And the outfall shouldn't be too close to the neighbor's property. They probably would not be too happy to see water being dumped right at the property line. If it ended up causing them problems, you'd be forced, rightfully, to undo it.