A reverse osmosis system that includes a housing having an inlet port, a permeate port and a concentrate port. The reverse osmosis system further includes a membrane element within the housing and (i) a first connector that has an end which is connected to the inlet port; (ii) a second connector that has an end which is connected to the permeate port; and (iii) a third connector that has an end which is connected to the concentrate port. The end of the first connector fits the inlet port but does not fit the permeate port or the concentrate port. The end of the second connector fits the permeate port but does not fit the inlet port or the concentrate port. The end of the third connector fits the concentrate port but does not fit the inlet port or the permeate port.