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A.O. Smith AO-US-RO-4000 4-Stage Reverse Osmosis System


Retail: $235.99 /ea
You Save: 15%
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Retail: $235.99
You Save: 15%
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Looking to upgrade your existing reverse osmosis filtration system, then consider the A.O. Smith AO-US-RO-4000 4-Stage Reverse Osmosis System. Hailed as the first of its kind by A.O. Smith to combine reverse osmosis, advanced A.O. Smith Claryum selective filtration and remineralization, the AO-US-RO-4000, reduces up to 99% of 88 harmful contaminants including lead, fluoride, asbestos, chromium, mercury, pesticides, pharmaceuticals, and chlorine. The AO-US-RO-4000 includes your first set of replacement filters, a reverse osmosis tank, 1 brushed nickel faucet, and other additional parts required for complete installation. Improve the quality of your drinking water at home and consider the A.O. Smith AO-US-RO-4000 4-Stage Reverse Osmosis System.


  • Brand: A.O. Smith
  • Part Number: AO-US-RO-4000
  • Filter Life (Months): 6
  • Filter Life (Gallons): 300
  • Filter Media: Carbon Block
  • Dimensions: 12.5" H x 4" W x 12" D
  • Flow Rate: 0.5 gpm
  • Operating Pressure: 125 psi
  • Operating Temperature: 40-90°F
  • NSF Certification(s): Standards 42, 53, 58, 401 + P473.

Compatible Filter Models:

The A.O. Smith AO-US-RO-4000 is the correct replacement for the following filter models:

  • A.O. Smith AO-RO-RM-R Membrane and Remineralizer
  • A.O. Smith AO-4000-CARBON Replacement Filter

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