Permits for in-ground cement block pool

[diyconcretepool]

A little over a year ago my family and I purchased an above-ground pool. It was fun for about 3 days out of the whole summer because there was no heater and it's an eyesore. It was a cheaper option than in-ground but now I've discovered how possible it is to make a good in-ground pool for under $10,000 and mostly DIY. I plan on doing this by excavating the area, making the concrete base, using cement blocks (with #4 rebar inside and filled with concrete) to create the walls, then backfilling and finishing the inside once the plumbing is done. These are all things my family and I are capable of but we live in a pretty strict county (Washington County, Oregon). Also, regardless of the county, the state of Oregon requires all contractors (which would be me) to be certified for each part of the work they complete (electrical, plumbing, etc) before applying for a permit and I'm not certified nor am I willing to hire other contractors to overcharge me for the same work. Again, I can do all of that work, I just am not licensed for it. So, here are my questions:

1. Would a concrete block pool like this even be permitted? I've seen a lot of these being made lately but mostly in countries besides the US so I don't know if it's limited what type of pool can be built here.

2. What can I do about the contractor part? I highly doubt that I'd find one to do it for even close to the same price I could do it for. I also don't know if any contractors would agree to this idea because it's not very common anymore.

3. What could happen if I just don't get a permit? Nobody would know if I lived in some secluded area but I don't, I live in a city with an HOA that literally watches for changes on satellite cameras. However, I've done a few projects without permits (some inside, some outside) and nobody has said anything so maybe they just don't care. A pool is different, though, because it's a large body of water that could potentially be dangerous... I imagine only bad things could come from them finding out I built one without a permit.

4. I've come up with an exact design down to the number of blocks I'll need, the amount of rebar I'll need, the amount of concrete I'll need, the amount of plaster I'll need, the amount of pool paint/sealer I'll need, and all of the other supplies I'll need like plumbing and a heater. I have sketches, a scaled-down model, and a computer model of the pool and its system but I'm not quite sure how to make the plans for the permit approval. How much detail do I need to give? Just the measurements? The materials? I don't know.