Which of the following describes a public water system?

A public water system is defined by its ability to serve a specific number of connections and the regulatory standards it must meet. The correct answer highlights that a public water system serves at least 15 service connections. This criterion is crucial because it indicates the scale and reach of the system, ensuring that it supplies water to a sufficient number of people to warrant public health regulations, monitoring, and compliance with quality standards.

Serving at least 15 service connections typically corresponds to providing water to about 25 people year-round, thus falling under the jurisdiction of regulatory bodies that oversee water safety and distribution. These regulations help protect public health by ensuring that the water is safe and reliable.

In contrast, providing water solely for landscaping or during emergencies does not meet the requirements of a public water system, as these scenarios do not guarantee the continuous and reliable service that public systems are designed to offer. Similarly, delivering water through unregulated pipelines does not fulfill the criteria, as public water systems must operate under strict regulatory conditions to ensure safety and reliability.