Grade C-
Cost Performance
WQA to NSF 58

Not NSF certified. Certified by WQA to reduce 15 contaminants including fluoride but not chlorine taste and odor. Reasonable system price and inexpensive replacement costs. Does not restore the healthy minerals lost in the reverse osmosis process.


From the manufacturer

The Watts Premier WP-5 (500023) Reverse Osmosis System is innovative in its one piece manifold design, thereby providing a seamless water path, effectively eliminating 17 different connections. It is a 5 stage reverse osmosis system that is NSF tested and certified against ANSI/ NSF Standard 53 for the reduction of the claims specified on the performance data sheet. The WP-5 System begins with stage 1, a five micron Sediment filter that traps particulate matter like dirt, rust, and silt that will affect the taste and appearance of your water. Stage 2 is a five micron Carbon Block filter that provides a reduction of chlorine and other materials that cause bad taste and odors. Stage 3 is an additional five micron Carbon Block filter which provides a greater reduction of chlorine (these are called PRE-filters because they filter in front of the reverse osmosis membrane). Stage 4 is the heart of the reverse osmosis system, the RO Membrane. This semi permeable membrane will effectively reduces TDS (total dissolved solids), Sodium and a wide range of contaminants such as Percolate, Chromium, Arsenic, Copper and Lead. It will also remove over 99.95% cysts such as Giardia and Cryptosporidium. Stage 5 is a high quality GAC final filter (this is called a final filter because it filters after the membrane). This final filter is a polishing filter and is used in the last stage of filtration.

  • Reverse osmosis filtration system

  • 3-gallon storage tank

  • Chrome airgap faucet

  • 5 stages of filtration

  • Adapt-A-Valve Water shut off valve

  • MFG Brand Premier

  • MFG Model# WP-5

  • MFG Part# 500023

  • Certified to industry standard, NSF/ANSI Standard 58

  • Califorina Certification 00-1452

  • Certified by WQA

  • 3 year warranty


From the manufacturer


Assembled Depth (in.): 6.0
Assembled Width (in.): 16.0
Assembled Height (in.): 16.0
Unit Color/Finish: White Filter Housings
Automatic shutoff: Yes
Filter change indicator: No
Faucet Included: Yes
Faucet Color: Chrome
Filtration method: Reverse Osmosis
Fitting size (in.): 1/4 in
Fitting style: Quick connect
Installation kit included: Yes
Item Package Type: Cardboard Container
Maximum feed water pressure (psi): 100
Minimum feed water pressure (psi): 40
Maximum feed water temperature (F) ,(C): 100° , 37.8°
Minimum feed water temperature (F), (C): 40° , 4.5°
Maximum filtered water flow (gallons per day.): 24
Product Depth (in.): 6
Product Width (in.): 16
Product Height (in.): 16
Product Weight (lb.): 23
Number of stages: 5
Water Filtration System Type: Under Sink
Water Filtration Technology: Reverse Osmosis
NSF Listed: Yes
Manufacturer Warranty: 3 year limited warranty

Note: Recommended hardness not to exceed 10 grains per gallon, or 170ppm. System will operate with hardness over 10 grains but the membrane life may be shortened. Addition of a water softener may lengthen the membrane life.

The operating pressure in your home should be tested over a 24 hour period to attain the maximum pressure. If it is above 100 psi then a pressure regulator will be required.


Customer Rating: 4.2 out of 5

Number of Reviews: 175

82 of 94 people found the following review helpful
1 out of 5 stars
Too much noise!
By macurban May 6, 2009
This review is from: Watts WP5-50 Premier Five-Stage Manifold Reverse Osmosis Water Treatment System (Tools & Home Improvement)
We were very excited to install and use the filter system for our well water. The installation went fine, the storage tank does take up space underneath the sink area. But the noise, we were not expecting. After the initial fill up and subsequent refills to settle the charcoal dust, we were ready to go. Each time the tank needs to refill you hear the trickle of water down the drain, 4 gallons of water is processed to make 1 gallon of filtered water. Plus a hissing noise similiar to a pressure cooker until it refills. We called Watts, and while they were very friendly, the rep. agreed "Yes, it is noisy." No solution was offered. We decided the cons outweighed the pros and uninstalled the system and sent it back. Had we known about the noise and the amount of waste water, we would not have purchased.

107 of 111 people found the following review helpful
5.0 out of 5 stars
Great Product
By K. Kelleron March 11, 2008
I have one of these that is about 10 years old now and it still works great. Of course I change the filters as recommended. We have a well with sulfur and iron in the water but the water out of this unit is perfect. We use the RO water in our coffee maker and we don't get any scale buildup. I have no problem getting replacement filters as these are standard 10" size. Watts Premier also has a great website and will even remind you when it is time to change the filters.
I just read an article about trace amounts of pharmaceuticals in the water supplies in many states. The article said that normal filtration does not remove the pharmaceuticals, but RO filtration does.

Data Source Reference: www.amazon.com