The end products are multiple.

• The product water using a typical US municipal feed water will approximate distilled quality water
•  Depending on if the RO is a consumer or industrial RO the rejected waste stream will have all the contaminants concentrated into a volume range of 1/4 – to – 17 gallons for every one gallon of clean water produced
• Either salt from a water softener regeneration or antiscalant chemicals will be released into the drain
• Sediment will accumulate on a prefilter which will either have to be disposed of, or rinsed clean and reused. In either case the sediment captured will be returned to the environment
• Activated carbon will be consumed either in a disposable filter or a backwashable carbon filter. Either way the spent carbon will need to be replaced.