https://www.energy.gov/eere/femp/rainwater-harvesting-regulations-map <-- this map is created by the US Department of Energy, and includes a visual guide to strict/loose/no restrictions, and if you click the state, you can view the precise laws regarding water harvesting in that state.
Out of the lower 48 states in the U.S., Colorado and Utah are the only states that are currently heavily regulated to keep homeowners from harvesting and using the rain that falls on their property. Many states DO have a 'Gallon Maximum' that you can harvest and store, keeping it out of the underground aquifers and other natural river systems.
Many states also have laws against the COMMERCIAL harvesting of rainwater.
Keep in mind: there are generally 3 categories of laws that restrict water use in the USA.
1) Groundwater - How many gallons can you draw up from the underground aquifers in certain time-frames?
These laws are generally done at a local level - in towns, cities, and counties.
2) Rainwater harvesting - How much water can you harvest, from rainfall that lands on your property?
3) Surface Water Rights - How much manipulation can you do to existing bodies of water, moving rivers, springs, and temporary (seasonal or storm-event) surface water flow?
These laws are ALSO usually done at a local level - in towns, cities, and counties. Sometimes these laws vary by the body of water, by city zoning, or by the property itself.
Building a huge pond could potentially be affected by all 3 of those types of laws.
- If you planned to use well water to help fill the pond, you may exceed your maximum allowed gallons-per-month drawn up from the groundwater.
- It may exceed the maximum allowed gallons of rainwater you can harvest and store for personal use. (However, check the time limits on these - some are gallons-per-day, some are per-month, or per-season
- Depending on the location of the pond, some states may fuss if you catch significant seasonal storm runoff that otherwise would have gone into the local rivers & downstream watersheds.
Your best bet is to narrow down your search to a couple states, and look up THESE SPECIFIC TERMS:
- [State] Water Allocation Laws
- [State] Laws Manmade Lake
Kentucky, for one, has a lot of areas with no Zoning (so you have a lot of freedom with how you build your house & use your property) and no regulations or laws regarding rainwater harvesting. In a lot of the state, it's pretty straightforward to get a USDA Rural Development loan for a homestead.
The absolute ownership doctrine in KY permits the landowner to extract an unlimited amount of water for use on overlying or distant lands regardless of injury to other users.
https://uknowledge.uky.edu/cgi/viewcontent.cgi?article=1112&context=kwrri_reports
The kentucky extension office even offers advice on how to build small manmade lakes & stock them for fishing and aquiculture.
https://freshwater-aquaculture.extension.org/wp-content/uploads/2019/08/MtGPondsSmallLakesKentucky.pdf