Question:

"The specifications on the Aquapurion Permeate Pump RO for water consumption claim much less waste than a standard unit. In a residential application on city water at 60-70 PSI input pressure how much waste would a standard RO and how much water would a Permeate Pump RO waste? Our water is about 25-30 grains hard and the input would be pre-softened."

Answer:

There is no accurate answer to your question. Here's why: Most RO systems waste 3 to 7 gallons of water per gallon made, however over the last quart or so (right before the tank shuts off), that edges up to 6, 7, 9, 11. 13, 15, even 19 to 1. So, if you take a glass of water out of the tank, it will waste a lot re-filling it. If however, you take a gallon or two out at a time and not lots of small glasses, the waste will not be as much. It's just that over time, most people have found that a permeate pump RO generally saves up to 80% in waste water. That is the claim that the manufacturer of the permeate pump (Aquatec) also makes. It also makes water faster and with essentially the same pressure coming out as you have going in. How much you actually waste depends upon how you use water. It's a good question with no exact answer. The bottom line is: A reverse osmosis system equipped with a permeate pump will waste less water, make better water, deliver higher water pressure and make water faster. If that's important to you, then the permeate pump is the way to go.