Drain Line out of the house too high for the Septic Tank Inlet

[esso72]

Hi all,

I run into a situation in which my House Pad where the septic will be is too high 25" - if I run all my slopes at 1/4" I barely come below the existing grade where the tank will be. Can I do a 45deg slope or less after the house in order to connect to the septic tank? This way I can buried my septic at least 2-3' deep. Also if you can share a website or documentation site that I can go to. See pics.

Thanks for the feedback

 

[sarg]

Just to mention .... 1/4" per foot is the minimum slope.
Mine is about 1/2" per foot .......... for the last 40 years.

 

[esso72]

Just to mention .... 1/4" per foot is the minimum slope.
Mine is about 1/2" per foot .......... for the last 40 years.

The company that is going to install the septic tank suggested to increase the slope slightly in order to get some depth(very similar to what you have). He also suggested to start deep. However my thought is if I start too deep and for whatever reason i need to open a hole in the house is going be too deep.

Thanks for the feedback!

 

[MicEd69]

Yes, a 1/4" per foot is the recommended slope. As sarg said, his 1/2" per foot has been working fine and probably won't cause you any issues either. But you don't want to go too much more as the flow rate could leave solids behind and possibly lead to an obstruction for long runs at say 1"-2" per foot slope. For big changes, 45 degrees is just fine, but again, you don't want to go much less than 45 degrees for a sudden changes.

 

[wpns]

Why do you want your septic tank to be so deep? At _some_ point, you are going to have to dig it up for inspection and possibly maintenance, so at the very least, make sure that you locate it properly so you can find it 30 years from now.

 

[sarg]

Now is the time for a Tank Riser Kit .... You'll appreciate it in the future. There are many styles and sizes.

 

[Joe-H]

Several thoughts, you're worrying about "someday" having to access the sewer outlet from the house. Why & when? If you need to get at that for some reason another foot of digging is not going to be your biggest problem.

You want the tank buried 2' to 3' deep, why? There's no reason for that, 6" is plenty, you're not going to be parking your car on it are you?

Listen to the guy on site, your installer knows what to do and you're paying him to do it. Second guessing his is just going to piss him off and gain you nothing.

 

[esso72]

Why do you want your septic tank to be so deep? At _some_ point, you are going to have to dig it up for inspection and possibly maintenance, so at the very least, make sure that you locate it properly so you can find it 30 years from now.

I dont want to be a particular depth, except to be in compliance by code to ensure there is no problem. I talked to the company who will install the septic tank Their suggestion was to be 2'. - This tells me that I need to start at deeper at my further drain. I need to recalculate the slopes at 3/8-1/2" again to see how much below the grade I am. One more question - the Input to the tank is usually 1' below the tank lid? or how deep the input entrance is from the top of the tank only using the standard riser.

Thanks for the feedback

 

[esso72]

Several thoughts, you're worrying about "someday" having to access the sewer outlet from the house. Why & when? If you need to get at that for some reason another foot of digging is not going to be your biggest problem.

You want the tank buried 2' to 3' deep, why? There's no reason for that, 6" is plenty, you're not going to be parking your car on it are you?

Listen to the guy on site, your installer knows what to do and you're paying him to do it. Second guessing his is just going to piss him off and gain you nothing.

Thanks Joe - I agree, i should not be worrying about that. Just trying to view all angles and asking for you all experience and suggestion. 6" to me is too shallow, but I dont have that experience or have not found the code or standard. The company mention something about 18"-24" should be fine.

 

[esso72]

Yes, a 1/4" per foot is the recommended slope. As sarg said, his 1/2" per foot has been working fine and probably won't cause you any issues either. But you don't want to go too much more as the flow rate could leave solids behind and possibly lead to an obstruction for long runs at say 1"-2" per foot slope. For big changes, 45 degrees is just fine, but again, you don't want to go much less than 45 degrees for a sudden changes.

Thanks Mic - For my own learning, In situation like these or when the terrain has a big change, 45deg or higher should be fine ok?

 

[MicEd69]

Thanks Mic - For my own learning, In situation like these or when the terrain has a big change, 45deg or higher should be fine ok?

Yep, 45 degrees or more works.

 

[Joe-H]

Plastic tank or concrete? If it's plastic look at the manufacturer's site for installation details. Here's one from Norwesco, it's approved for AZ use. 6" to 3'. Here, which isn't AZ so I don't know your specific state requirements, new installations must have the risers and exposed lids so no matter how deep you put it you still have the lids showing.

 

[esso72]

Plastic tank or concrete? If it's plastic look at the manufacturer's site for installation details. Here's one from Norwesco, it's approved for AZ use. 6" to 3'. Here, which isn't AZ so I don't know your specific state requirements, new installations must have the risers and exposed lids so no matter how deep you put it you still have the lids showing.

It will be concrete

 

[Twowaxhack]

We like to set our tanks shallow. 6”- 18” deep at most. That’s to the top of the lid. Your inlet is even lower.

1/2” per Ft fall will work perfect. Don’t worry about having too much fall.