Product review (3 stars): The real problem is the drain tube under the sink
Paid no attention to the other reviews. Bought it anyway. It did leak at first but took it apart to find out why.  There is a brass tube that dumps excess water from the RO membrane to the drain. The brass tube is open to the air and sprays a small jet of water down the drain tube and goes into the drain under the sink.  The drain tube was clogged and the water was flowing out the back slit in the faucet base.  Cleaned the drain tube and it works like it use to. Still, strange design that will wash your counter top if it gets clogged.  When you change the filters, clean the drain tube also.