What on earth is this tank for?

[MikeMichaels]

Hello, there is a mystery cement tank buried right against the house and right next to the well. Please take a look at these pictures, they will show better than I can tell.


At first I thought it was a perimeter drain cistern. Or somehow involved with the house perimeter drain. But I was able to see straight to the bottom, the water was clear, yesterday and there is no outlet at the bottom. There is what looks like a drain on the bottom but it is has the plug in so is not draining. I now think it is connected to the well system somehow. But I replaced the well pump last year and never noticed any weird connections to this tank. But two things make me suspect it is well related: it's proximity to the well and the water pipe coming in. That pipe you see in the picture doesn't go into the basement anywhere I can find, so it might be connected to the well entry pipe underground somewhere between the well and the house.

If anyone solves this mystery I will be both grateful and very impressed! I've asked many people and nobody has a clue. Even the guy from TC Hafford Basements had no clue. It isn't septic or grey water because there is no smell and the water is crystal clear. I could see down to the bottom. Thank you!!!

 

[SHEPLMBR]

Are you on a septic system? Or municipality sewer?

 

[MikeMichaels]

I am on a septic. The septic tank is on the opposite side of the house. The old septic tank location is also on the oppposite side of the house. This was installed in the era before they started putting septic tanks right next to the foundation.

 

[wpns]

A previous shallow well? Maybe for irrigation? That black poly pipe and plastic fittings look like irrigation system to me. Pump it out and see if it refills?

 

[sawguy]

Abandoned cistern?

 

[RS]

I suspect a cistern too, being that it's right under a downspout.

 

[MikeMichaels]

Thanks everyone! I will try to drain it tomorrow. I was thinking of doing that anyway so I'll get on it.

If it is a rain water catchment cistern what do you suspect the water line coming in is for?

Thanks again!

 

[wpns]

If it is a rain water catchment cistern what do you suspect the water line coming in is for?

I _suspect_ it's where the water goes _out_ of the cistern into the irrigation system, and that there used to be a pump in the cistern. But that's a guess.

 

[Valveman]

Might still be a submersible pump or just a foot valve at the bottom of that poly pipe? Have you tried to pull it out?

 

[MikeMichaels]

The poly pipe is just cut off clean about 18 inches above the bottom of the pit. No pump or any fittings there. I could see it with my eye but the camera didn't pick that up. The water is clear enough to see the bottom. There might have been a pump at one point, there is about the right amount of room between the hose cut off and the bottom. I am going to drain it and will post another picture. I am hoping it doesn't refill. I don't think it will.