Hopefully, some Civil Engineer may know the answer to this: I am on well water as is most of the residents in my county. What, if anything, would the county have on file regarding water tables and/or maps of the aquifers and how they might inter-connect underground, if at all? Ideally, I’d like to see how deep and wide my well’s source is…or, are there no such public records? Who would I go to see to ask? Would I start with public works?
Your local public works, water department, or engineering department (usually part of the DPW) might have something. Water table information isn’t really standard, but these departments often wind up with a random assortment of plans.
You could also try the USGS. They have that information for certain areas, and may have it in yours.
I’d start with the local water department (mind you, I don’t work for one): if any one would know how far down the water is, I’d think it would be them. As you might guess, the answer can be fairly complicated - a) it can change seasonally, I think; b) it can change based on various local geological features; c) there can actually be different levels of separated acquifers and ground water. Et cetera. But you won’t know if you don’t ask.
If everyone is on wells, it is unlikely that they have a water department.
I entered "<countyname> water table**"** into Google™ and got several hits linking to the Country Extension Service (in Ohio it operates out of Ohio State University; in other states it is also usually linked to one of the state schools) and to the Ohio Department of Natural Resources. Between the two sources, I found a lot of what the OP is seeking. Of course, it is unlikely that anyone has ever mapped an entire county down to the parcel level for every possible well situation. They generally have maps of soil and stone substrate, sometimes with aquifers noted. If your houses are all on well, they are likely to all be on septic systems and you might be able to find a copy of the perk tests and the well tests done during the sale of each parcel in either the deed or some other record at the court house. (Someone at the county should be able to tell you which department (often the department of Health) handles those records.)
My experience will be common for the Great Lakes states and has a good chance of being good for the Northeast and extended Midwest. For the South or far West, I will not make any guesses–you might try my Google™ search using your own county.
Your state government will likely have a Department of Environmental Quality (or equivalent) that deals with natural resources. They’ll probably have a wealth of information on the various aquifers in your area. I just met with a DEQ water resources person on Monday regarding this exact question.
On re-reading your post, it sounds as if you also need to contact the local building permit center. They may have a copy of the building permit package for your house (depending on when it was built). That will probably include not only the permit for the house construction, but the permit for the well installation and the septic tank as well.