Installing new septic system

[stumpfield]

Is there any potential problem/disadvantage installing the septic tank too low and too far away from the house and have long sewer pipes? Other than cost a little more of course... I'm getting a septic system install and I want it about 9' lower than it normally should so the tank will be located lower than the basement floor. This requires going down a slope about 300' away from the house.

No bath room in the basement level in the plan now but may want one later if we decide to finish the basement. I'm thinking it's a small investment now. But I don't want to deal with any problem now for having it too far away. Common sense says lower is better but my common sense sometimes doesn't make good sense One potential concern may be not enough water flow to push the solid waste to the septic tank if too away.... It may dry up and clog the pipe???

Any thoughts?. Thanks.

 

[Egon]

Put some cleanouts along the way.

 

[jinman]

Egon is right! Use 4" pipe as a minimum and a cleanout about every 75-100 ft. I've seen 6" pipe carry over 600' with a decent slope.

 

[keving]

Egon is right! Use 4" pipe as a minimum and a cleanout about every 75-100 ft. I've seen 6" pipe carry over 600' with a decent slope.

FWIW, I just did about the same as you are looking to do and the guy that put mine in recommended to put the tank closer to the house rather than the drainfield. This eliminates the solids having to travel such a long way.

 

[stumpfield]

FWIW, I just did about the same as you are looking to do and the guy that put mine in recommended to put the tank closer to the house rather than the drainfield. This eliminates the solids having to travel such a long way.

That's what I'm worry about... but how do you put the tank closer to the house and still lower than the basement floor? My land slopes away from the house and need at least a few hundred feet of run to get it below the basement level. Do you need sewer pump for the bathroom in the basement?

 

[LC Brewing]

Your other option is to install a lift sump/pump for the basement only. These are fairly common for houses with basements - especially since most basements are designed with only a single half- or full-bath and MAYBE a laundry room. Usually, the system isn't getting a lot of use through the basement, so a lift pump (about $400 to $500 installed complete) is easier than relocating the septic tank (or often the ONLY way to make it work due to grade of the site).

I would discourage putting the tank that far away, but if you are set on placing the tank that far from the house, then make sure your line is correctly sized (4" for a home with three to five toilets). 6" would be overkill (and could have flow issues due to too large of a cross-sectional area), but 3" would be too small unless you only have two toilets in your house. Code will require an in-line cleanout every 100' and/or 135-degrees of horizontal bend (i.e. one 90-elbow and one 45-elbow). I would go closer than that - maybe 50', just because that long of a run with solids is asking for trouble. At no point should the line run at more than a 3% (3/8" per foot) slope, and never less than a 1% (1/8" per foot) slope. 1% is minimum for flow, and 3% is maximum to avoid the liquids over-running the solids and causing the system to back up. If you have to make a more severe drop in elevation, then you need to maintain the optimum 2% grade to a point where you can use a 45-degree vertical (steep enough that the solids cannot stop), then step the line down (picture a terraced effect here), then out horizontally again at 2%, etc. It would be wise to place a cleanout at the upper 45-degree elbow on each step for easy access in case you do have an issue.

As someone else stated, you are best to place the tank close and the drainfield farther away because no solids are sent to the drain field. You can even (like I did with my house) have the drainfield higher in elevation than the house and pump to it (added $500 to the complete/installed price of my system and allowed me to put the field whereever I wanted it). By pumping to my drainfield, I only had to bury a 1" pipe from my tank to the drain site, and could route it any way I wanted.

 

[LC Brewing]

I just re-read your post and caught the part about "no bathroom in the basement level in the plan right now".

If you are putting in a basement, and you will have a slab poured for the floor, then you better think about that bathroom now. Your idea of "small investment now" regarding tank location is minor compared the the "small investment" of having the plumbing needed under that slab when you get ready to put a toilet and shower down there. Add to that the fact that when you do add a bathroom, you'll have to route the vent piping from those drains all the way up to the roof of your house - or at least high enough that they will tie-in to the vent system from another floor above flood level (considered 6" above the "flood level" of the highest fixture - or typically 42" above the floor itself) of that floor (code requires that the vent for any level cannot tie into the waste "stack" of a higher level).

Most jurisdictions will not have a problem with you showing future bathrooms in "unfinished" spaces, and would rather see the plumbing installed now than have a possibility of unsafe installations down the road.

Chances are, you already have some "ideas" in your mind about what the basement will look like some day. Bite the bullet and nail down at least that bathroom location so you can run the underground and above ground waste and water rough-ins, and you'll thank yourself later.

If this is a house that is already built, then you can disregard this post.

 

[stumpfield]

If this is a house that is already built, then you can disregard this post.

LC Brewing, thanks for the info. No, the house is not built yet. Still in the planning stages. The septic is going in now for hookup to the RV. We'lll stay in the RV for a while. We are building the barn 1st with a bathroom/laundry in it. The house will be at least another year or more away. The bathroom in the barn, RV hookup and future house will tie to the same septic system. I want to make the right decision now so I don't regret later. I'm off-grid. No power easily available. So, I'm trying to avoid anything that requires power.

 

[Highbeam]

I like the idea of a decently long distance from the home to the tank. It gets the unsightly tank lids out of the immediate yard and allows for flexibility in regards to expanding or adding on to your home in the future. Pump truck access to the tank can be better if the tank is not right beside the home.

Then there's the overflow issue. I don't like dumping sewage on the ground BUT, if there is a pluggage in the very necessary outlet filter from the septic tank then I want the sewage from my home to overflow onto the ground and not into the basement and I want that overflow to be a reasonable distance from the home so that I don't need to smell it. The outlet or effluent filter prevents bad stuff from leaving the tank and fouling your drainfield and I believe it is required in my state and I agree with using one.

I would set the tank 300 feet away and stick to a 2% slope as LCB details. I would go for more than a couple of vertical feet between the septic tank outlet and the basement slab elevation to allow for some overflow head. Place one of the cleanouts very near the tank and cap it with a pop up lid set below the slab elevation.

Are you looking forward to RV life for over a year?

 

[stumpfield]

I like the idea of a decently long distance from the home to the tank. It gets the unsightly tank lids out of the immediate yard and allows for flexibility in regards to expanding or adding on to your home in the future. Pump truck access to the tank can be better if the tank is not right beside the home.
.............
Are you looking forward to RV life for over a year?

Highbeam: That's exactly what I'm thinking. As far away from the house and as low as practical... but just want to make sure it doesn't create another problem.
Yes, It's going to be RV life for a while. At this pace, it may be longer. The building boom in CA is great of the contruction trade. It's tough to find anyone willing to work. Especially in a remote area. Most contractors take the easy pick 1st.

It's been a year. We just got the road in, building pad graded. Got all the permits and septic is going in tomorrow and starting digging the footings for the barn.