The issue becomes it takes a certain type of mindset to want to understand how it works and properly operate it. The owner himself said there's tons of valves in the system. He'd need to develop an O&M manual for his setup prior to selling the property. It's probably pretty straight forward with only a couple seasonal adjustments, but that's more than enough to make most people's eyes glaze over.
Yeah, When you build something yourself you often forget that to someone on the "outside" it may look like a complicated mess / magic when it really is fairly straight forward.