1. RO systems do not remove hydrogen sulfide gas (rotten egg smell) from well water. Hydrogen sulfide is a “gas” and an RO membrane will not remove gas from the water.
2. An RO system has a ratio of +/- 1: 8 gallons of usable water. Eight gallons of water is required to produce one gallon of usable water.  The remaining seven gallons of water is wasted.  An average family of four  uses +/-100 gallons per person/per day (400 gallons).  With an RO system this same family will use 3200 gallons per day with 2800 gallons being wasted.
3. An RO system removes all the minerals from the water. This pure state of the water is chemically aggressive and is detrimental to copper pipes, fixtures, rubber plumbing parts and will cause them to fail over time.  For this reason, Calcium has to be re-introduced into the water to alleviate this situation in perpetuity and is an ongoing maintenance issue.
4. RO systems are expensive to install and maintain.
5. RO systems are very inefficient when well water has a TDS (total dissolved solids) over 600 ppm in the water.
6. RO systems are slow in producing water, requiring large storage tanks in excess of 500 gals or more.  In the event of mechanical breakdown,  the customer can be without water for prolonged periods of time.
7. The replacement of the RO membranes is expensive.
8. On homes with a common large well supply and irrigation pump, short cycling of that pump can be a problem over time for the pump motor causing pump failure.

This information is factual and can be verified by the internet (Google).