Which of the following is NOT a type of private water source?

The classification of water sources typically distinguishes between private and public sources. Municipal water is a public supply that is treated and regulated, making it not a private source.

A trickle system, often used for irrigation and landscape watering, is a method of delivering water that can operate from both private and public supplies, depending on its context. Natural springs are also considered private sources, as they often belong to individuals or entities that access the spring directly.

River water, while it can be diverted for private use, is generally considered a public resource since rivers are waterways shared by the public and regulated by government bodies. This makes river water less closely tied to private ownership compared to springs or equipment like trickle systems, which are often directly under the user's control. Thus, river water stands out as not being classified as a type of private water source, as its access and usage are influenced by public regulations.