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Tank inlet lower than outlet

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WillC03

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Hey all,
Have a couple questions for anyone who knows about leaching fields/old septic tanks.

Basically I'm replacing my leaching field because it wasn't done properly (dirt clogged the lines and no gravel or lining around the pipe). But I noticed that my septic tank seems to be backwards, the inlet is lower than the outlet. Was this done on purpose for any reason, and is there a way to correct this? I cannot afford to get a new tank and I'm going to teardown and rebuild the house in 5 years or so.

Edit: I'm wondering if a baffle would work so my leach field pipes don't get clogged from the inside this time.
 
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breplum

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I have NEVER worked around septic equipment, but knowing other plumbing drainage system traps in the business, the reason for the outlet being higher would be to maximize the clearest flow on the outlet, allowing maximum settlement of solids even after baffles.
Does the tank say "inlet" and "outlet"?
I haven't noticed any responses from plumbers on this forum lately about septic system questions.
 

FishScreener

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The inlet and outlet are typically at about the same height, and up pretty high on the wall of the tank.. Typically there is a baffle which keeps the floating solids on the inlet side. there is gap under the baffle where the black water goes across to the outlet, and then out to the leach field.

The floaters are digested by bacteria, and then fall to the bottom of the tank as sludge. As the tank fills with sludge, the water has a harder time getting under the baffle and out, and the tank is plugged. And you have to pump it. It is better if you get it pumped every years, to avoid the potential of the sludge being pushed out into your leach field and clogging it.

So, I can’t speak to the design of your system, but the outlet is always kind of high. but typically the inlet is at about the same height.

Do you have enough grade from the house to the tank, so you can raise the inlet? Or, would you have to add a pump to make it work? The installation might be coming in at the bottom just because there wasn’t enough grade to come in higher, and grinder pumps were rare and untrusted.

The fact that it is coming in from the bottom, would keep the sludge stirred up, and headed out into your leach field.
 

mark3885

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Is there a plastic filter on the outlet side of the tank? If there is no gravel or filter sleeve around your leach piping , then you will have soil flowing back into your leach piping. As far as your tank , the outlet should be the same height or lower than the outlet. Here is a schematic of my tank with the outlet , 3 in lower than the inlet. Only way to correct it is to replace the tank, I would leave it and keep the outlet filter clean.
 

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fixitron

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The outlet hole is typically a bit lower than the inlet hole. The water level sits at the bottom of the outlet hole so that every time water flows into the tank, the water level rises and water flows out the outlet. If the tank is backwards, then the inlet pipe would be under water all of the time.
Outlet filters are a new element that may be found in engineered systems. I have never seen them in older, standard tanks. There should be no dirt falling back into the tank. The outlet pipe is solid until it gets to the leach field, where any perforated piping should be sitting in stone.
 

WillC03

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Thanks for the replies.
The tank looks pretty rough inside and out, I think it was formed in place. I can't really see past the inlet hole so maybe it slopes up sharply just out of sight.

Like you've said, I think the main problem I'm going to have is that solids will get into my outlet pipe because it's just one big pit with no baffles or divider.

I dug up right to the outside of the tank and the pipe is an old type of black rubber or maybe plastic that crumbles off in flakes. I'm going to replace the pipe and redo the leaching field with gravel. I'm thinking I could make a baffle with a 3" tee-wye on the inside. But is there a way to seal around a pipe if I stuck a piece of 3" inside the old black pipe that sticks out of the tank?

Edit: Here's the outlet stub I chopped off, it's about 3.5" inner diameter.
outlet.jpg
 
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Jeff Handy

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Your sewer pipe might be Orangeburg pipe.

Glorified cardboard coated with tar.

You should replace it now while you are addressing the other issues.
 

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