A method of maintaining accuracy in the measurement of a parameter of industrial water utilized in an industrial water system, the method comprising: (a) contacting an industrial water stream at an industrial water stream pressure with at least one of a wetted surface of a pH sensor and a wetted surface of an oxidation-reduction potential sensor ; (b) measuring pH and/or oxidation-reduction potential of the industrial water stream ; (c) contacting at least one of the wetted surfaces with a cleaning solution comprising urea hydrogen chloride for a first period of time and at a concentration sufficient to clean the at least one of the wetted surfaces ; (d) re-contacting the industrial water stream at the industrial water stream pressure with the cleaned at least one of the wetted surfaces for a second period of time, thereby measuring pH and/or oxidation-reduction potential of the industrial water stream using cleaned pH and/or oxidation-reduction potential sensors , (e) creating a recovery curve related to the measured pH and/or the measured oxidation-reduction potential using the cleaned pH and/or oxidation reduction potential sensors ; (f) repeating steps (a) through (e); (g) comparing the respective recovery curves created via step (e); (h) if the comparison of the respective recovery curves demonstrates acceptable sensor degradation, continuing to measure pH and/or oxidation-reduction potential of the industrial water stream with the pH sensor and/or the oxidation-reduction potential sensor ; and (i) if the comparison of the recovery curves demonstrates unacceptable sensor degradation, removing from service the pH sensor and/or the oxidation-reduction potential sensor that demonstrates the unacceptable sensor degradation. (a) contacting an industrial water stream at an industrial water stream pressure with at least one of a wetted surface of a pH sensor and a wetted surface of an oxidation-reduction potential sensor ; (b) measuring pH and/or oxidation-reduction potential of the industrial water stream ; (c) contacting at least one of the wetted surfaces with a cleaning solution comprising urea hydrogen chloride for a first period of time and at a concentration sufficient to clean the at least one of the wetted surfaces ; (d) re-contacting the industrial water stream at the industrial water stream pressure with the cleaned at least one of the wetted surfaces for a second period of time, thereby measuring pH and/or oxidation-reduction potential of the industrial water stream using cleaned pH and/or oxidation-reduction potential sensors , (e) creating a recovery curve related to the measured pH and/or the measured oxidation-reduction potential using the cleaned pH and/or oxidation reduction potential sensors ; (f) repeating steps (a) through (e); (g) comparing the respective recovery curves created via step (e); (h) if the comparison of the respective recovery curves demonstrates acceptable sensor degradation, continuing to measure pH and/or oxidation-reduction potential of the industrial water stream with the pH sensor and/or the oxidation-reduction potential sensor ; and (i) if the comparison of the recovery curves demonstrates unacceptable sensor degradation, removing from service the pH sensor and/or the oxidation-reduction potential sensor that demonstrates the unacceptable sensor degradation. <EOS>