Question: What’s the life of a RO membrane?

Answer: The life span of a RO membrane depends on 1) the contaminant level of your water, 2) the maintenance program you follow for changing your pre-filters and 3) the amount of water you use. Membranes can usually operate well for a couple of years but they will last up to five or more years under good conditions. To test the membrane, measure the total dissolved solids (TDS) of the water coming into the membrane and the RO product water as it leaves the membrane housing outlet. Compare the two TDS numbers by dividing the RO TDS by the incoming water TDS. If the percentage is greater than 12%, you need to test again in a few weeks and be prepared to replace the RO membrane when the percentage approaches 15% as that would indicate your rejection has fallen to 85%. You will likely also notice that the RO membrane will be producing less water as the rejection percentage declines.