Abstract: A water manifold is usable in the construction of a fluid-based heat-transfer system for space heating, the supply and distribution of potable water, and other applications. The water manifold is formed from a number of elements in a flexible manner, in that the elements are assembled as needed for a particular application. A plurality of manifold segments 100, each supporting a pipe directed away from a main pipe, transfer heat to a specific area, and may be be connected in a linear manner, as required by the design of the application. A cross tee segment 300 is attachable to the manifold segments, and may be used to support a thermometer unit 200, an automatic air vent or other apparatus. A spigot 400 is attachable to the cross tee segment, adjacent to the thermometer. An open end cap 500 provides a male plastic fitting connected to a brass female fitting, thereby allowing connection of the manifold to metal plumbing. A closed end cap 600 allows the manifold to be terminated.