PRESTIGE H2O / WATER, UNDERSTOOD
Reverse osmosis water use: compare like for like
Reverse osmosis produces both treated water and reject water. To compare efficiency, ask how much reject water is produced for each unit of treated water and under which test conditions. Confirm the direction of any advertised ratio; treated-to-reject and reject-to-treated express the same relationship in opposite ways.
Make the ratio unambiguous
Ask the supplier to write both quantities with labels and units. As an arithmetic example, 2 gallons of reject water for 1 gallon of treated water means 3 gallons enter the system for those outputs. This example is not a specification for any Prestige product.
Verify a WaterSense claim
EPA's point-of-use RO specification requires labeled systems to produce no more than 2.3 gallons of reject water per gallon of treated water. Check the official model listing and its certified reduction claims. A manufacturer's brand name alone does not establish that every product carries the label.
Ask what could affect the comparison
Use the documentation to compare equivalent conditions and the system you would actually receive.
- Exact model and configuration
- Definition and direction of the advertised ratio
- Test pressure, temperature and other stated conditions
- Relevant efficiency listing and reduction claims
- Care requirements needed for intended operation
Choose the treatment goal first
Efficiency matters after establishing which treatment is appropriate. Compare the proposed RO system with other documented ways to meet your goal. A water-saving statement should not substitute for evidence of the required treatment performance.
Questions and answers
Does a 2:1 ratio always mean the same thing?
No. Ask whether the first number represents treated water or reject water. Have both quantities written out before comparing models.
Does WaterSense verify every possible contaminant claim?
Review the exact model's certified claims. A label is not a statement that every possible contaminant is reduced.
Can I estimate household savings from a product ratio alone?
A household estimate also needs expected treated-water use, comparable operating assumptions and the current system's performance. This guide does not promise a savings amount.