FR Chuck...well I am no expert. But I can explain what I would look for in trying to find a septic tank. Normally I believe if you walk around your home and see an area that is raised up in elevation and at the top of the raised elevation...there is a concrete pad or something to that effect. On mine, their is a concrete pad with somehooks on it. I assume this is where the cleanout crew would pull tha off and have access to the tank. I have a friend that owns a clean out crew. Last I heard it was $300ish to pump the tank. Again, I am not totally sure of this price. Also, I would assume that the price would depend on some factors.
1. Where it is located?
2. How easy is it to get to?
3. How big of a tank?
4. Location of where you live?
Again, I am not totally sure on this info I am just assuming.