This is not an ad! Take the quiz and get custom recommendations!

Pentair Water Solutions PRO-RO Reverse Osmosis System Review

This system is no longer recommended!

While this is a good system, we no longer recommend it. For the same price, you can get a similar system that is more efficient and has a better warranty. Please see our current list of recommended RO systems to learn more.

If you are looking for a smaller, easy to manage system and have low water volume needs, then consider the PRO-RO undersink water filtration system from Pentair Water Solutions (formerly Pelican Water).

Pentair-Pelican PRO-RO Reverse Osmosis System
Pentair Water Solutions PRO-RO Reverse Osmosis System

This system is unique in several ways:

  • Integrated chassis, 2 gallon storage tank, and filtration cartridges take up very little space
  • Comes standard with an air-gapped faucet in your choice of three finishes
  • Made in the USA

System Design

Integrated Components

The PRO-RO combines the system chassis, filter cartridges, and 2-gallon pressurized water storage tank into one compact unit.

This simplifies the installation and maintenance of the system.

It also reduced the space used under your sink by around 50% compared to standard undersink RO systems that have a separate water storage tank.

6 Stages of Filtration

The PRO-RO has 6 filter stages divided between two easy-to-maintain cartridges.  No tools are needed to maintain this system.

The first cartridge contains stages 1-4, including:

  • 20 micron sediment pre-filter
  • Granular Activated Carbon (GAC) pre-filter
  • Reverse Osmosis (RO) membrane
  • Granular Activated Carbon (GAC) post-filter

The second cartridge contains stages 5 and 6, including:

  • Granular Activated Carbon (GAC) polishing filter
  • Calcite remineralization postfilter adds back calcium and magnesium minerals and raises pH

All undersink reverse osmosis systems waste water as part of the filtration process. The PRO-RO wastes 2-3 gallons per 1 gallon of filtered water, depending on the water pressure entering the system (higher is better).

Air Gap Faucet

An air gapped RO faucet is designed with a siphon break to prevent backed up waste water from re-entering your water filter, just in case there was ever a problem with your plumbing.

The system comes with your choice of faucet finish, all at the same price:

  • Chrome
  • Brushed nickel
  • Oil rubbed bronze

Easy Maintenance

With just two filtration cartridges to change and no tools required, the PRO-RO is a very easy system to maintain.

The stage 1-4 cartridge should be changed every 18 months and the stage 5-6 post filters should be changed every 6-12 months.

Bonus Features

NSF/ANSI 58 Certification

Certified by the Water Quality Association against NSF/ANSI Standard 58 for the reduction of substances including:

  • Arsenic
  • Barium
  • Cadmium
  • Chromium 3 and 6
  • Copper
  • Cysts
  • Fluoride
  • Lead
  • Radium 226/228
  • Selenium
  • Turbidity
  • TDS (Total Dissolved Solids)

While this is the list of what the system is certified to remove, reverse osmosis and granular activated carbon will remove or reduce hundreds of contaminants.

WaterShield Autoship Club

Pentair Water Solutions offers the WaterShield Autoship Club that will ship the necessary replacement filters to you automatically and on the correct schedule. 

Plus, signing up for a WaterShield subscription when you purchase this system will save you an extra 10%!


  • Compact, integrated design
  • Air-gapped faucet is required by some building codes
  • Your choice of three faucet finishes at no extra charge
  • NSF/ANSI Standard 58 certified by WQA
  • Remineralization stage produces mineral water and raises pH
  • System and filters made in the USA
The PRO-RO takes up less space under the sink.
The PRO-RO takes up less space under the sink.


Compared to other recommended reverse osmosis systems, the PRO-RO falls short with:

  • Low production rate of just 18 Gallons Per Day (GPD)
  • Average 2.5 gallons waste per 1 gallon filtered water
  • 1 Year Warranty is decent but not great


Pentair Water Solutions makes highly-rated whole house water filters and water softeners.  The undersink PRO-RO system is made to the same standards here in the USA.

If you are looking for a small system that is easy to manage, or need a system that comes standard with an air-gapped faucet, then check out the PRO-RO 6-stage reverse osmosis system.