Flow test data on concrete pressure pipe are gathered, tabulated, and analyzed in this article. The purpose of the analysis was to determine what flow formula is most applicable to concrete pressure pipe operating within the diameter and velocity ranges found in water supply practice, and determines flow coefficients for pipeline design. For the range of velocities encountered in water transmission, the empirical Hazen‐Williams formula most closely matches the test results, and certainly gives results of acceptable accuracy. Substantial rational justification of this formula is also provided by the Morris isolated‐roughness theory of flow.