Live Chat
Filters Fast Logo Header
bbb A+ site secured
Free Shipping on orders over $75 | FREE 365-DAY RETURNS

Product Availability

Please provide your e-mail address below to receive a notification when this product becomes available:


Thanks! We'll send you a notification when this product is available!

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


Free Shipping Item Banner
Retail: $195.99 /ea
You Save: 9%
As low as
Retail: $195.99
You Save: 9%

Special Order. Ships in 5 to 6 business days.
Sign up for the Home Filter Club during checkout.
You choose how often you want your filter, and we take care of the rest.
Are you a purchasing agent? Purchasing for a business?
Contact [email protected] to gain access to case quantity discounts, account management and terms!
Product Information

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


Customer Reviews:

There are no reviews for this product yet!

Related Categories: