[Mystriss]

We're thinking about replacing our septic since it's nearly 20. The current system isn't "big enough" to handle our 4 bdrms and we want an endless pool/hot tub so we're looking at upgrading. Best guess the current field is 20' x 60' x 2-3' high and seems to have one trench/line - or at least there's only one access pipe on the far end, vs 2 on the nearer end (plus five or so near the house.)

Think I could do a 100' x 17' x 2' mound with two trenches/lines to handle our waste water? Or is it 100% based on perc test even with a raised bed/mound system?

Random aside, can you border the leach field's "cover mound" in a retaining wall? The mound was pretty abrupt when we moved in here and we spent a lot of money trying to make the rest of the yard's grade look nice, but I was thinking it'd be neat to have more of a stepped mesa kind of thing instead of a slope this time around.

 

[chandler48]

The domed system does not rely on buried pipe to do the dispersal of the water. The only pipe you have is where it enters the first dome. From there it is purely percolation. If the first part of the domes gets filled, the water moves to the next section and so on. I had 200' installed at our rental cabin and the inspector and installer both said it would last to the next millennium, since basically your solids are taken care of in the septic tank and only liquid comes to the field.

 

[rjniles]

Most localities will require you to have an engineered system

 

[Oso954]

What is the frost level in your area ?

Here is an article on cold weather/mound systems in Minnesota.
http://minnesotabrown.com/2015/03/minnesota-winters-confound-mound-septics.html

I'd talk to some local septic pros for some advice on how well mound systems work in your area.

 

[Mystriss]

So it sounds like I can probs leave the existing field and just upgrade the tank at the house? Does it matter that the mound's sunk a bit since it was installed or is that normal? Maybe 6" over-all.


So we're kind of out of code jurisdiction, though I do try to stick to Anchorage's requirements, which this tank was to spec so long as we turned a bedroom into a "bonus room" heh We do have a high water table here so we'll have someone design everything to get from the tank (by the house) to the field - which is maybe 35-40' away from the tank.


I'm just trying to get a handle on the size and shape of leach fields in general. I'm trying to plan the location of a new shop but the leach going behind the building makes the existing field/mound's grade a bit wonky so I'd like to elongate it so I don't end up with the back of the shop "walk-out basement" style.


Foundations have to go at least 6' deep up here to get below the frost line by code IIRC. Or well around where I am, further north they have permafrost and have to go to the bedrock (Although it wouldn't be too big a deal for me personally as we're pretty close to bedrock.)

 

[chandler48]

We had to track past a bad leach field to get to good soil, so it's about 90' of hard pipe, then turned into the domes. They went about 150' out, turned and came back 50' with proper dome spacing.

 

[taylorjm]

We have to contact the local health department for information on sizing septic systems.

 

[lenaitch]

Eve though your are out of Code territory, good on your for using a nearby code as a foundation. You are likely in similar terrain and still have to be concerned with proper percolation, nearby wells, etc.
I get that it may be undersized for current use, but I wouldn't call a 20-year septic 'old'. Properly designed and used they should last for decades. Also, I'm not getting how adding a hot tub/pool impacts things, unless you need the space.

 

[Ghostmaker]

My area no longer uses mounds they went to sprinklers

 

[Mystriss]

Eve though your are out of Code territory, good on your for using a nearby code as a foundation. You are likely in similar terrain and still have to be concerned with proper percolation, nearby wells, etc.
I get that it may be undersized for current use, but I wouldn't call a 20-year septic 'old'. Properly designed and used they should last for decades. Also, I'm not getting how adding a hot tub/pool impacts things, unless you need the space.

You're pretty close actually. The existing is like this:

Area behind the shop when we moved in and the pipes at the end of the line or whatever - tank connects up on the other side/end:

This is what I want to do:

Now I'm pretty sure the new shop footprint doesn't go past the green area in the behind the shop picture. I need to measure to be sure, but it's WAY to cold to go out there atm. I was hoping to extend back about 25-30 feet so I can have 16' clearance between the shop and the house. We have 13-14' now and I feel like the shops too close to get equipment through if they ever bring the city sewer line close enough to connect up to or something.

This shot gives a better perspective because the end of the field and the power line post look way "closer" than they really are in the above behind the shop picture:

*The "hill" behind the shop is allegedly mostly a combination of the excavation of the attached garage/dining room addition on the house sometime in the late-70s, the shop's perimeter/slab sometime in the mid-80s, and the current leach field's installation in 2000 and NOT part of the field itself. Who knows if that's true, prior owner couldn't remember a lot of the work he'd done to the place (was a building contractor so no doubt it just blended into his actual jobs,) but I do remember he was quite confident we could make the shop bigger if we wanted. (We had immediately started fighting over who got it when we looked at the place lol)


I was told that adding a hot tub required an upsized septic system at some point in the past, no idea if it's true. Also, we had some "not our guys" pumping our tank for a few years, and also had a 7.3 quake 13 miles away and shallow that probs settled things. When our guy came out last summer he said the tank was half full and solid. Said he "back flushed" it three times and got basically nowhere... He thinks the other folks might have been sucking the wrong half of the tank - the sucker pipe is short and near the deck, vs the taller ones out past the grill are much more "hey look at me!" I actually have no idea if the other guys did the right pipe as I didn't pay attention, they'd just come do it and leave a bill on the door :/


Anyway, I want to bury the power lines to the house/shop which may or may not disturb the field AND we need to move the tank to the other side of the house so our pumper guy doesn't have to buy yet another longer hose to service it (we still feel bad about it lol) when we put on the new front garage -- all of which probably requires us to redo the field regardless of the required size and shape of it. So we might as well make it fit into the new lot layout.

 

[Mystriss]

As an aside, because I've been reminded by all this.

When we moved in here back in 2001 neither of us had ever had a septic system. First guy we called to come pump it in 02 was "our guy" - I told him we had no idea what we had gotten into and he took a good three hours out of his day to have a little "class" with me and the boys about the do's and don'ts and how it worked and all that.

He did our service every year up until four or five years ago when he retired, and most years I'd go out and we'd chat it up and yuck about the stench of four teenage boys and such. I kinda miss him heh

We had just found out last summer that one of his apprentices had ultimately taken over the business. I do recall the kid when he was training, though he's grown up so much I hardly even recognized him. Anyway, we are quite happy to be back with them, even if the "other guys" didn't actually mess up and suck the wrong side, like it was just settled from the quake or whatever.

It's kind of funny how easily we can slip into not "noticing" the folks who sorta work for us and make our lives work. I try to remember them all every year. Coffee for the mailman who kindly drives packages all the way to the front porch so we don't have to go to the post office all the time. Cash and cookies/candies for the garbage truck folks who even now make sure to put our trash can well onto the driveway so the plow trucks don't wreck it (even though the whole thing is automated now.) And, the pumper guys, who I'd kind of written off and stopped paying attention too without even thinking about/realizing it because things got busy for me...

I'm not sure what I'll find to give the "new" pumper guy... Previous owner of the business came for conversation and company, not sure about this "kid" (okay he's older than my boys heh,) but he even offered to try to drive his truck over here in the winter with no studs to suck the tank and try to save us - above and beyond really cause it's not at all his problem. The smallest things can buy loyalty from a customer. I told him to just head on over whenever he wanted to suck the tank in the summer, and if he wanted some chatter to feel free to knock on the door - Maybe he'd like a glass of lemonade and a gas mask hahaha

 

[chandler48]

If you have an existing dome system, they can probably add on to the free end, sweep it around and continue it so you don't have to do anything to the existing field. At 20 years, I doubt you have a leach field problem.

When they came to dig up my old field (gravel and perf pipe) we found an occlusion 20' out from the septic tank. The remaining 70' had never had water run through it. It still had proprietary stickers on the inside of the pipe from our local hardware store. It had been there since 1978.

 

[Mystriss]

Wow... And you never had any issues with it's leach performance? Eh I probably shouldn't be too surprised, regulations tend to be higher than necessary to CYA heh



Anyway, alright so it sounds like I can go ahead with my idea and we'll be able to fit the field around my plans (maybe even reuse it) That should be good enough to get my idea plans in order for when I to talk to our builder guy