I am a real estate appraiser. I recently came across a large barrel like tank that was embedded into a concrete block wall. It had several valves on the lower part of it and a glass tube like gauge for measuring the level of the contents. The owner represented that it was a cistern. It appeared to be an oil storage tank. Could it be a cistern. I would like to include the picture that I have but was unable to do so on this site. I would love to send it to anybody who might be able to help me with this. Thanks.