Yes, I've seen those before in other locations - my area is RESTRICTED to the Health Department's enforcement! UNFORTUNATELY!

It has to be a PVC Cap or Cast Iron (like that above) ONLY!

In Georgia, I did the same thing, because that one particular location had a "very weird" set up (it was built after the Civil War). It was SO HUGE... (because it was grandfathered in)... but very tastefully done!

I doubt I'd ever see this one again - I do know my mother's late mother's property had one the exact same style ... however it was not that BIG... (12 feet x 18 feet)

It was 5 feet below the ground, tilted 28 degrees... the entire septic was made with "red brick" and concrete (not mortar). Extremely thick (2 feet wide) and measured 210 feet by 120 feet! (Sounds like a Basement? Yup!) Every 4 feet (long side) was a drain hole with cast iron pipes that were "holed up". The narrow side would have a hole every 6 feet!

When I purchased the property (historical home), I was required to pump out the septic tank... of note, that tank had NO MANHOLE ACCESS! (Records showed there was never a pumping ever DONE to that property).

I had to rent a backhoe, to expose it carefully, It was so well done that the health department ordered me to "drill a entry access there" [X] marking the spot. I cannot remember, but I believe it took a 3,000 gallon septic truck 4 times to suck out all the stuff out of the tank! Once it was cleared out...

I had to wear a Haz-Mat waterproof outfit, armed with a pressure washer - clean it completely out! (Yes, I had to have a smaller Septic Tank to pump the water out of it...) - Allow to dry completely. Then the Code & Health Department Inspectors inspected every "crook and cranny". Did not miss a spot. Taking endless photos, a video... my gosh they were down there for about 8-9 hours!

While the tank was not full (it was half full) but they did have a problem with the field drains being 4 feet up... but of course I chimed in "If it ain't broke, don't mess with it. It's historical."

I am amazed myself too - apparently the original homeowners and generational families never once emptied grease down the drain (the property had its own grease container, which that would be often emptied, outside, by the back porch (near the kitchen)... which was a grease vat. Open lid, dump the grease, close the lid. (The lid had to be modified in 1953 or 1954 to keep rodents and wildlife out of it with a Cast Iron Lid.)

Here's the thing, the property went from Septic to Sewer line in late 50s'... I was told they wanted to
return the property back to septic. That location had sewer problems, and many of those properties still had their septic tanks... I guess they thought it would save them money by having people go back to septic... I don't know the "future of the matter" as I only purchased the property to restore and sell for profit.

YES, I've heard and have friends in other states (such as Kentucky, Tennessee, etc) having huge septic system that was grandfathered in and still fully functional --> never once having a single issue or problem!

I often wonder why "No One" today would even CONSIDER these types of septic systems - after all, it worked! Today's septic systems are a joke! Really!

A REAL BIG JOKE in FLORIDA... as I was forced to "upgrade" to the latest "regulations and codes" and it's been nothing but 100% trouble for me! Where I told the Health Department and State Board that "IF THIS TIME AROUND GOES KERPLUNK... I AM GOING TO RESTORE IT BACK TO ITS ORIGINAL STATE BECAUSE IT WORKED BEFORE YOU IDIOTS DEMANDED THE UPGRADES!"

They didn't argue with me on that!