Finding old septic tank access lid


  #1  
Old 07-01-18, 11:59 AM
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Finding old septic tank access lid

Hello,

I have an old septic tank made of cinderblock walls and a concrete lid on my property. I have found one of the 6'' inspection/pump out ports but want to know where to find the 24'' concrete access lid so I can fill the tank with gravel. The inspection port is clear so my neighbor said the tank is definitely empty if you can see down there. I have hit what I think is the concrete lid with a home made soil probe but do not want to dig up the whole thing if I can just find the access to fill it. I do not know any dimensions of the tank except that I have been told it is 8 or 9 ft deep and that there should be a 24'' access. Any help is appreciated.


Steve
 
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Old 07-01-18, 03:27 PM
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Can you use a mirror and a flashlight to determine which way the tank (if it is rectangular) is oriented? Then you will at least have an idea in what direction from the small access hole you need to dig.

Or you could use a driveway snow edge marker stick to reach down and swing from side to side and get a rough idea of the locations of of the septic tank walls.
 

Last edited by AllanJ; 07-01-18 at 03:49 PM.
  #3  
Old 07-01-18, 05:37 PM
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I'd try and scrounge up some old political campaign signs, they're usually a plastic bag streteched over a ~ 24" wire " U " frame. Those "U" frames are quite handy...

Having two wires to probe with allows you to find the EDGE of the tank fairly quickly,

after a bit of guess work, one wire will hit the top of the tank, the other dives into the soil.
Leave the wire prong hitting the top of tank wher it is, pivot the other prong around, after a few jabs you'll find the edge of the tank- Mark that, leave the prong at the edge in the ground, pivot the wire frame around and jab until you find the next edge- mark that, and repeat until you get an idea where the edges of the tank lid are.

Once you know where the the tank lid is, "walk" the metal prongs back and forth until you find a place where one prong is 1-2" higher thatn the other, that tells you that one prong is on the tank, the other is on the lid. Pivot around as before to figure out where the edge of the lid is.
 
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Old 07-02-18, 03:03 AM
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want to know where to find the 24'' concrete access lid so I can fill the tank with gravel.
Since you are decommissioning the tank - why not just bust a hole in the top if you can't find the lid? The gravel doesn't care where it goes in at.
 
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Old 07-02-18, 05:27 AM
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Thanks for the ideas. I will go clean up some of the political trash and get the tank outlined and maybe just start digging in the middle. This is definitely something I am going to do on my own and do not want to break the tank lid and have it collapse in. I appreciate the help!
 
  #6  
Old 08-12-18, 06:15 AM
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Do you think the tank is really 8-9 feet deep ?
 
  #7  
Old 08-13-18, 05:47 AM
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Lid should contain some metal hardware for lifting. Got a friend who has a metal detector?
 
 

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