I failed to mention in my last column that the pitless adapter along with the submersible pump and the captive air tank have, in my opinion, been the three great advances in pump system technology in the last 60 years. Some may argue that the constant pressure system is a fourth great advance, but I have not had much experience with these and I try to limit these columns to things I have personal experience with.
I have mentioned that early pitlesses were basically one of two types: the O ring type or what I call the union type. You can refer to my October 2015 column for more details on this. When we first started using pitless adapters here in Michigan, it was the late 1950s and metal casing was still about the only thing being used. Pitless adapters in those days were purchased with a specific bury, which was most usually 3 foot, 4 foot or 5 foot. This footage dimension was how deep the service line was below the top of the ground and allowed for the top of the adapter to stick up at least 12 inches above grade. Now this was before we had a full state-wide well code, which today mandates a minimum of 12 inches from the ground line to the top of the adapter. I have seen adapters sometimes flush with the ground or nearly so, and others standing as high as 3 feet above grade. In new construction especially, getting an accurate reading of the final grade is sometimes difficult. I can remember a public supply well I drilled in the 1970s where I left the pitless a good foot and half above grade. For some reason, the residents added some filler and the last time I saw this installation, the top of the pitless was way less than a foot above grade. Extending a pitless adapter in some designs is not easy.