The present paper deals with electrostatic characteristics, i.e., space charge density and electrostatic potential under turbulent flow in pipes with and without leakage. This paper considers the charge conservation equation and proposes theoretical models able to calculate the space charge density of intact and leak pipes. The distributions of the space charge density and electrostatic potential are investigated through numerical simulation. For the case study used for validation purposes, the space charge density obtained by numerical simulations is compared with the experimental results. The results show that the proposed model is capable of calculating adequately the distribution of the space charge density in pipes. The effects of flow velocity and pipe diameter on the electrostatic characteristics of intact and leak pipes are then investigated. The results show that, for intact pipes, the maximum electrostatic potential appears in the central area of the pipe and increases slowly with the increase of the velocity, while the maximum potential decreases with the increase of the pipe diameter. For leak pipes, the maximum potential takes place at the leak aperture, and increases with the increase of flow velocity and pipe diameter. In order to reduce the possibility of electrostatic discharge, the flow velocity ought to be controlled below 2.5 m/s, and the pipes with smaller diameter shall be used as far as possible when meeting the requirement for use.