The following is an answer to one of our customers who asked, How many gallons will my membranes last. So I thought I would post the answer. Ahh, There is no direct answer to your question. There are several factors that determine membrane life. Chlorine will destroy a membrane in no time flat. It is very import to keep your carbon up to date, if you think it maybe has a little time left on it, CHANGE IT. A few more tips that will greatly extend your membrane life; Don't run your membrane to lean, by cutting your waste stream to less than the recommendation. There are companies that tout their membranes need less waste, those companies sell a lot more membranes, because their customers destroy them. “Waste Water” is an integral part of the RO process, it is the vessel that removes the TDS. Technically, waste water, is called concentrate. Scale is another enemy of membrane life. Running hard water will prematurely scale your membrane, rendering it useless. Softened water is ALWAYS better. Heat; exposing your membrane to temperatures above 110 F will destroy it too. With that said; the best answer maybe in our experience. We have had customers whose membranes have lasted 10 years; we have had customers trash their membranes in a few months. If you have questions, call us. We can help with your unique situation.