Menards has PT rated for underwater/in ground use, but it's special order.

We have a pier that has been in place since 1977 using 2" galvanized pipe for uprights, pounded into the lake bottom. It's never been taken out for the winter. The pier is on the SW side of the lake, and has seen ice 3' thick.

If you can figure out where the water level will be at full pool, and the water level will stay pretty constant, then I'd look into the metal pipe system.

If the water will fluctuate, then I'd look into a floating dock.


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