@Zeona McIntyre I own a couple of properties upcountry on Maui and have cesspools on both. The larger property actually has two cesspools. Setting aside the ick-factor, it's not necessarily a bad thing. If it drains well and is in good shape, it can result in lower ongoing maintenance cost than a septic system. The risk is if your cesspool fails or the year 2050 arrives, whichever happens sooner. The current regulations per Hawaii DOH are that new cesspools and substantial repairs are prohibited. You can still pump and service your existing cesspool up until 2050, which is currently the year by which all existing cesspools are subject to a mandatory septic upgrade requirement. Who knows if they stick to that timeline...or eventually cave to public pressure and delay it and/or install more public sewer lines.
In the meantime, you are free to buy and sell properties on Maui with cesspools. There are no restrictions or upgrade requirements upon transfer of ownership.
I'm going through the septic upgrade process now for a 5BR house, and it's not fun. There are not enough engineers working on Maui right now, so the design docs alone are running $3,500+ with a 4-6 week timeline. Add another 6 weeks for DOH approval and $20,000 or so for actual system install. That's all assuming you have enough usable and (somewhat) level yard area for a drain field. If you don't have the yard square footage, things get more complicated fairly quickly.
Having been through the process a couple times already, I would recommend having Kekai's Pumping or Akamai Pumping find the cesspool and check it out before closing to assess your risk of near-term failure. The odds that a typical property inspection report will have anything useful to say about the cesspool situation is basically zero.
Hope that helps! DM if you learn anything interesting or want to chat further.