What is the RO
unit rated at (GPD)? Usually, you will get about 50-75% of this amount of water. RR is right about the waiste. RO
Units produce a lot of waste water, mine is about 4gal of waste to 1gal of RO
water at 100GPD.
Did you flush and charge the unit prior to use?
You may have air trapped in one of the lines, so you can try bleading them one at a time.
You can try twisting the filter chambers counter clockwise to break the seal and releace any trapped air.
Do you have a pressure guage on the unit? What is the PSI at the unit intake? If it is under 40psi, you will need a pump to increase the water output. I think 75psi is what you want.
I have seen people run their waste lines to their washing machines and use that water on their clothes. Others catch the waste water and use it for watering their lawns and washing their cars.
Hope this helps