Need advise on finding abandoned septic tank

[Jon229]

65 yr old house, originally on septic, but about 50 yrs ago transitioned to city sewer. I want to park vehicles and a heavy RV over the general area of the tank. But how do I find that tank? I've poked around with rebar (maybe did not go deep enough about 12-16") and also cannot find a tank lid. The lateral for the city sewer generally goes through the area where I suspect the tank is and through the area where the leach field is presumed to have been located.

The area I believe the tank islocated is flatter than the surrounding terrain I have a drawing but that has not helped me locate the tank. I'm guessing that when it was installed it did not follow the exact specifications for location.

I presume tanks from the 50's were made of concrete. Did they all use rebar or possibly not? I'm thinking about renting a metal detector but unless constructed with rebar I do not know if that will help me find the tank and I do not know if I need a specific type of detector.

The reason I want to find the tank is to make sure it has been slurry sealed and safe to park over.

Any thoughts?

 

[Reach4]

Usually on the opposite side of the house from the well.

Usually on the downhill side

Often in line with the vent on the roof.

In line with where the sewer line heads out... Nevada... guess no basement.

Use a probe for feeling down through the soil. Could use 48 in. Soil Probe with Steel T-Style Handle and Sharpened Tip. That septic tank would be concrete.

 

[Sponsor]

 

[Jon229]

Use a probe for feeling down through the soil. Could use 48 in. Soil Probe with Steel T-Style Handle and Sharpened Tip. That septic tank would be concrete.

No well, city water. Yes, I'm looking on downhill side, in line with where existing sewer line is now located. Obviously, the existing line must run to one side of the tank. I also have the original plan, but I found nothing at that location, but only went down 16in.

I've been using 5ft piece of rebar, the soil probe looks easier, but my soil is quite rocky.

Thanks for the info

 

[Jadnashua]

The house I grew up in was built in 1954...it had a steel septic tank. That lasted maybe 15-years, and then we had to replace it. The new one was concrete. So, while yours could be concrete, it might not be.

If you can find the original outlet to the septic tank, it they usually tried to make that a straight run out to the tank. The leach lines might be perpendicular to that run to the tank.

If the original outlet to the septic tank was cast iron, you could likely find it with a metal detector if you own one, or have a friend that does.

 

[Jon229]

The house I grew up in was built in 1954...it had a steel septic tank. That lasted maybe 15-years, and then we had to replace it. The new one was concrete. So, while yours could be concrete, it might not be.

Interesting. A metal tank would fit the timeline between installation and transition to city sewer (that city line is ~4 ft below grade - determined by measurement from cleanout). So by now the tank could be rotted & gone. But then there should be a depression if it rotted out. I don't see that.

I've looked at rentals for metal detectors. They have the kind you would use at the beach to find coins and stuff. This type might be insufficient for detecting a rebar reinforced tank unless it was right at the surface.

I've ordered the previously mentioned soil probe. My rocky clay soil may not be friendly for this tool but it was cheap enough to take a chance on it.

 

[Bannerman]

My Grandmother's home had been equipped with a concrete septic tank which was pumped out when the house was connected to municipal sewers. I recall my Uncle breaking the tank's lid into small pieces with a sledgehammer so the open tank shell could be filled with soil to regain the use of that section of the yard without concern of the tank ever collapsing.

If your property was equipped with a concrete tank, perhaps it was similarly destroyed to recover the use of that portion of the property.

 

[Jon229]

breaking the tank's lid into small pieces with a sledgehammer so the open tank shell could be filled with soil to regain the use of that section of the yard without concern of the tank ever collapsing.

That would be ideal. And it is why I want to locate the tank so I can verify it's status and satisfy myself there is no threat of collapse. Hopefully the contractor who made the city connection did this but I have no way to find out without checking the tank. I've cleared most of the area of shrubs and vegetation but there in no obvious signs so far. I gotta try to find that tank.

 

[Reach4]

The center of my buried cleanout for my septic tank is about 17' from my house foundation. While that is not universal, it might offer a line to start probing.

 

[Jeff H Young]

Ive never abandoned a septic. Could be they filled it in with dirt, sand or gravel. I thought that was a requirement when hooking up to public sewer? somebody ought to be able to "witch" the drainline maybe get reading over tank as well

 

[Storm rider]

Depending upon which county you are in, the health department MAY have a record of the location and disposition of the tank at the time of connection to the sewer. That is about the time when they were microfilming permits as permanent records in the larger counties.

 

[Jeff H Young]

several suggestions for you good luck!