gardening over mostly unused septic field

Hello folks! I'm writing here because my partner and I are considering a new location for our zone 1 garden beds. So many of our garden areas have wound up untended due to being too far from our house, and we would like to right that situation... The problem is that the area that makes the most sense to start is close to our our septic system.

This is not a standard septic system. There is a tank, but no finger system, only a dry well, which is a brick cistern that the effluent falls into, landing in the bottom of the small pit and draining between the gaps in the bricks. To me this seems worse for the ground water, but less likely to contaminate the soil that would be inhabited by annual garden veggies. In addition, we have been using a composting toilet for well over a year now. Only very small amounts of greywater and urine are moving through the system, and we only used our flush toilet for a few months after the previous inhabitant likely went without water for years. We also plan to build raised beds, but are not quite sure how much depth we will add at first.

I could be totally reckless, but this just doesn't feel dangerous to me. Is there some dynamic of soil that I should know about that would make this more dangerous than I think? I don't even feel like this would be a bad idea without using raised beds, but it seems like raised beds would definitely work, given that people often use them over soil containing lead and such things. What else do I need to know before making this decision?

Personally, I wouldn't plant food crops directly in that soil. All sorts of stuff gets poured down the drain. Without lab analysis, it's difficult to know what the biological and chemical load will be. Offhand, I can't see a reason why container gardening or tall raised beds would be a high risk.

Soil that is kept wet with high nutrient water will tend to be anaerobic, which I suspect (?) may help harbour nasty organisms and not be good for plants. Have you dug a few test pits down to the subsoil?

I tend to agree with Douglas. I might be tempted if you have a different system for grey water.  Raised beds might also tempt me.

First no raised beds over a septic field. They are not worth messing with unexpected effects can be expensive. You may find you need the evaporation from the soil surface to keep it all working, we had some "helpfull" friends cut a load of an invasive bush down while they were housesitting for us. We were perfectly happy with their work until the septic stopped draining. those bushes had been sucking enough water out of the very wet ground we had to keep the whole thing ticking over, even though they weren't growing over the drain field (they were downhill of it)  Other than that It would not bother me at all especially as you don't use it, I probably would want to dig down and see/smell what it was like near the pit I would doubt it comes up into the topsoil, ours which is a similar brick tank doesn't.

Dietrick, this thread has some good information posted by our member Dr Bryant Redhawk:

https://permies.com/t/54087/septic-leach-field-plant-edibles

Here is another thread that might be helpful:

https://permies.com/t/34452/Septic-Soil-Long-Safe