A Unified Net Present Value Framework for Residential Water Leak Repair

This paper presents a unified net present value (NPV) framework for evaluating residential water leak repair decisions. The model integrates direct water cost, time-varying carbon pricing associated with water treatment and distribution, an explicit valuation of user annoyance, and repair cost. A worked case study demonstrates application of the framework to a common residential faucet leak using conservative assumptions. The paper is self-published, intended as a technical note and decision-analysis example, and has not undergone peer review. It accompanies a public essay on AI-enabled decision frameworks but is designed to stand alone as a quantitative reference.