Patent ID: 7964103

Claim:
A computer-implemented method of monitoring the performance of a reverse osmosis membrane in a drinking water supply system, the method carried out by a computer program, the method comprising the steps of: determining the flow of a predetermined amount of water through the system; measuring the initial water conductivity downstream of the reverse osmosis membrane; calculating, using the measured initial water conductivity, a threshold trip point which corresponds to a predetermined total dissolved solids rejection ratio, wherein calculating said threshold trip point includes: measuring said initial product water conductivity values; equating an average of said initial product water conductivity values to said total dissolved solids rejection ratio; and calculating said threshold trip point as a percentage of said average; storing the threshold trip point in memory of the system; routinely measuring the water conductivity downstream of the reverse osmosis membrane; determining whether the water conductivity, as routinely measured in the prior step, is below the threshold trip point; and providing an indication upon determining when the water conductivity is below the threshold trip point.