Hi fallingwaters. You're selling your home soon and yet still want to invest 40k? I seriously doubt you would make that money back.

Sadly it seems as if landscaping isn't worth much except as a 'perk', much like a backyard shed is nice to have but doesn't make the home worth anything more. If all things were equal between two homes except one had nicer landscaping, then that home would probably sell quicker, but I doubt it would sell for more.

You home does sound very lovely. I wonder why you feel such costly work needs to be done before you sell? Personally I'd clean out the weeds, shove some stepping stones into the slope and call it good.

Can you do comps for other homes like yours that feature water? Do they sell for 40k more?

Hmmm well it sounds like you can see the waterfull and swimming holes if its part of the view, and go down and swim on some sort of path through the weeds? So technically that's all useable by some new buyer.
The septic however is something a buyer will hope is up to snuff and part of the purchase price.
So without knowing more details I might do the septic and leave the rest (hopefully thats a lot less than 40k).
The details I'm wondering about it are - will doing the retaining wall landscaping not be able to be done later without compromising the new septic? If that's the case I can see your dilemma, if not, just do the septic and let the new owner find their own dream for the back. MHO FWIW

I agree with Mary's post, sounds like the septic should be done and also wonder if there is a reason to do the retaining wall now.

I wouldn't put the wall in. You won't make the money back. The way I see it as a gardener, I would rather choose all of that myself then to be stuck with having to live with hardscaping someone else picked that I might not like.

I tell my sellers the following:

There are things that preserve value, and there are things that add value.

Systems are "expected" by buyers. Meaning they won't pay more for new windows, new HVAC, new roof, etc, as they just "expect" those to be in good condition. It's a bonus for buyers when those items are new, but I've never had one buyer say "I'm willing to pay 10k more for that house because it has a new HVAC and new roof". These things help preserve value to a buyer, but it's rare they'll offer to pay more for them.

Kitchens and bathrooms of course add value. (How much depends on your area.)

Unfortunately for most, landscaping falls right in the middle. It neither adds or preserves value (dollarwise), though it can make your home more attractive and hence sell faster, but it won't necessarily sell for more.

I've had sellers who've spent 40k on landscaping who are shocked that buyers just don't really care. Yes, they think the improvements are nice, but they're not willing to pay extra for them.

If you plan to sell, do the septic. If *you* want the wall and steps, do it for yourself, but don't expect to see too much of a return from it when you go to sell.

thanks for your thoughtful resonses. my thinging goes like this. the homes with the fancy backyards around here do get the bigger prices on avaerage. outdoor rooms are all the rage here. the terrace will add to the outdoor living space,by tripling it. right now the front of the house has a landscape with privacy fence,hidden garden aspect to it with the stone patio and grape arbor. these are in front of the sliding glass doors into the living room,and is a very nive outdoor space,but on the opposite side of the house from the water.
currently ,on the water side,the kitchen and the living and dining space looks out at the water (and the messy slope below),there are three doors off of that side of the house and they lead to a three foot path which leads to the very narrow and creaky old staircase down to the waters edge. my plan will use boulders collected from the property to create a series of the walls,which will create terraces for lawn chairs,bbq,plantings,etc. i feel it will 'finish' the house,if that make ssense. and the septic is functional,but could be made new and with an added bdrm capacity,so i definetly want to do that. our excavatior seems to think it a fairly easy,though time-consuming job,most of the materials are on site,except for the special septic sand and for the engineering fee for the new septic. the new septic alone will cost 20 k,,the remaining dollars for the labor to move the stone into position and backfill. the wall will be quite long and tall,the slope from the house to the water is quite steep.
the other factor to consider is how long will it take to sell? the excavator is willing to wait for his money,but if the market remains so sluggish it may take a while. meanwhile,i could start making payments to him while i enjoy my new backyard. i have a feeling that if i can wait it out,our little ski area may become the next secret 'in' spot,for a bunch of reasons. a huge development company has purchased most of the mountain and is making plans for lots of luxury secondhomes and the like. while i'm anxious to move,,it may make sense to hold on for another few years,with my improvments in place and be ready when the area takes off again.otoh,with it finished as i envision it,,i coud use it as a vacation rental also. can't now without better access to the water.
so,as you can see,a lot to consider here.

Think twice about redoing the septic. If it's working and has been maintained there should be no reason to redo it.
As a buyer when I see new septic on a listing I wonder what what else was not maintained, what other kind of plumbing problems there are.
For SOME buyers a new septic can be a huge red flag, others will see it as a perk HOWEVER putting in a septic often means lots of digging up of the yard and having to redo parts of it more money spent and why? Is it really needed or are you thinking that putting in new will help your bottom line? If it's the latter I can tell you straight out it won't.

I wouldn't do either if you plan to sell. With a slow market and prices dropping how do you think you'll be able to re-coup it?

People expect a septic to be functional and will not pay the extra 20K for your house just because it is new. Why would you replace one that is functional so somebody later could add another bedroom? Not money you'll recoup at all.

Landscaping is personal and I'd rather do my own hard scaping and pay a lower price.

If it looks bad to access the area to swim, how about just doing some shredding and clean-out of weeds/brush whatever it is that makes it look less than appealing and get a walkable path in for access.

If you are planning on staying then do it for your own enjoyment and don't worry about whether you'll get the money back or not.

Is this leveling so you can get a patio in there or ? That might make a difference as a patio does have some worth in an appraisal. If you are selling would a deck be more economical? A deck also has some appraisal value.

the septic is working,but clearly at the end of it's lifespan. a realtor has already told me to be prepared to give back 25 thousand for a new one. so in my thinking it make sense to get the new one with one added bdrm capapcity as a selling feature. it will probably be an out-of -state person who buys this as a vacation home,according to the realtor they usually want all systems new or newly replaced.
hubby says the capacity for another bdrm is appealing to buyers,they see that as money in the bank. plus,our terraced back yard will throw our home up there with the big boys,the one's fetching the bigger prices. my husband will run the water and electric himself to a spot chosen as ideal for a future hot tub,and also has his eye on a spot for an outdoor kitchen space. since he's a plumber and the neighbor an electrician,these items can be done quickley and cheaply.
the men feel that building the bare bones walls and terrace with hot tub ready space and outdoor kitchen space ready to go will add some real appeal to the place.
i'm tempted to go with the project,,lots of return in living space for little risk. especially if i can start making payments to the excavator before we sell. and of course while it sells,it'll be a nicer place to live! or rent--with the added septic capacity i could rent without worry to groups for wedding,etc.
thanks for helping me brainstorm it all out.

"the septic is working,but clearly at the end of it's lifespan. a realtor has already told me to be prepared to give back 25 thousand for a new one."

Don't listen to a realtor's opinion of your septic system.

Have it inspected by a professional septic installer. It might be fine, it might need a $1500 repair, it might need replacement. Only one way to find out.