Raintree™ Undersink Filtration System

Professional-grade filtration. Clean, great-tasting water straight from your tap

Cover of Raintree Undersink ultrafiltration water filtration system.
Photo of the Undersink Ultrafiltration System installed in the cabinet under a kitchen sink. Image highlights the space saving design and small footprint. There is still lots of extra storage space left in the cabinet.
  • Front Cover of the Undersink Ultrafiltration system
  • Photo of the Undersink Ultrafiltration System installed in the cabinet under a kitchen sink. Image highlights the space saving design and small footprint. There is still lots of extra storage space left in the cabinet.
  • installation fitting. Angle stop adapter fitting for installing tubing for undersink water filtration system to main water line under the kitchen sink.
  • installation fitting. 3/8" x 3/8" x 1/4" T fitting for installing tubing for undersink water filtration system to main water line under the kitchen sink.
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Under-Sink Ultrafiltration (UF) Filtered Drinking Water System

Under-Sink Ultrafiltration (UF) Filtered Drinking Water System

$189.00 USD
$189.00 USD
Sale Sold out
Select Your Final Stage Filter:
Select Your Installation Fitting (see below for help):
View full details

How to select your installation fitting

Compare your existing water line to the photos below and select the one that most closely resembles your setup

Angle Stop Adapter

Select this threaded fitting if you have a flexible hose-type water line.

T Fitting

Select this 3/8" x 3/8" x 1/4" push fitting if your water line is rigid.

Why Choose the Raintree™ Water Filtration System

Reliable, multi-stage filtration for clean, great-tasting water.

Multi-Stage Filtration

Reduces sediment, chlorine, bacteria, and contaminants while retaining essential minerals for clean, great-tasting water.

NSF Certified Materials

Components manufactured with NSF-certified materials for safe, high-quality performance.

Easy Installation

Designed for straightforward under-sink setup using standard household tools and push-fit connections.

Long-Lasting Filters

Filters last up to 12 months, saving you money and reducing waste.
Replacement FiltersRefrigerator Connection Kit
Installation InstructionsFilter Change Instructions

Filter Set Components

Primary Filters

1. SEDIMENT + CARBON

  • New and improved, now with added carbon block!
  • Dual-stage filter design for better water filtration
  • Stage 1: captures particles such as sand, silt, rust, dust, dirt, and pipe residue
  • Stage 2: features a carbon block that reduces chlorine and other unwanted impurities
Pre Carbon GAC water filter. Used for water coolers and undersink water filtration systems.

2. PRE CARBON

  • Granular Activated Carbon filter uses adsorption process
  • Contaminants are attracted and adhere to the carbon material like velcro
  • Reduces chlorine, VOCs, THMs, and other unwanted impurities
  • Protects and extends the life of the Ultrafilter Membrane
Ultrafilter membrane water filter. Used for water coolers and undersink water filtration systems.

3. UF MEMBRANE

  • Semi-permeable membrane that physically traps suspended particles as small as 0.01 micron
  • Reduces bacteria, cysts, microplastics
  • Excellent contaminant removal
  • Allows beneficial trace minerals and fluoride to remain in the finished water

Choose Your Final Stage

Select your polishing filter
Post Carbon GAC water filter. Used for water coolers and undersink water filtration systems.

4. POST CARBON

  • Premium granular activated coconut shell carbon
  • Improves taste and reduces unwanted odors
  • Delivers a smooth, fresh finish

Alkaline Mineral Carbon block water filter. Used for water coolers and undersink water filtration systems.

4. ALKALINE MINERAL

  • Activated carbon block and functional ceramic ball media
  • Adds beneficial trace minerals
  • Produces mildly alkaline water
  • Improves taste and reduces odors
  • Provides a crisp, refreshing finish

$30.00

Optional Add-On

Refrigerator connection kit

Refrigerator Connection Kit

Allows you to connect the undersink filtration system to a refrigerator, ice maker, auto-fill coffee brewer, etc.

Can be used with or instead of a dedicated filter faucet

Kit Includes:

  • 15ft of 1/4" poly tubing
  • 7/16" refrigerator inlet adapter
  • 1/4" T fitting
$30.00

Details

  • High-efficiency, space-saving drinking water filtration system featuring a 5-6 stage Ultrafiltration setup (number of stages based on selected configuration).
  • Easy installation and filter changes with no-tool filter replacements
  • NSF certified materials and components
  • 5-year limited warranty
  • Lifetime technical support
  • 90-day money back guarantee

Connects to standard cold water supply using 1/4" poly tubing

Compatible with the following:

  • Dedicated sink-top filtered water faucet
  • Auto-fill coffee brewers
  • Instant-hot drinking water heaters
  • Refrigerator water dispenser/ice maker

When connected to a refrigerator, this system replaces the manufacturer's filter using a bypass plug (sold separately - search your refrigerator model number to identify the correct plug)

  • Sediment + Carbon filter (5 micron mesh and Carbon Block)
  • Pre Carbon filter (GAC)
  • UF Membrane (0.01 micron)
  • Post Carbon (GAC) or Alkaline Mineral filter (Carbon Block and Ceramic Balls)
  • 8 ft of 1/4" poly tubing
  • Installation connection fitting
  • Filter flushing kit

Designed for straightforward under-sink installation using standard household tools.

Installation is simple:

  1. Mount faucet
  2. Mount undersink system
  3. Connect 1/4" tubing from cold water supply riser to filter system inlet
  4. Connect 1/4" tubing from filter system outlet to filter faucet
  5. Flush filters

For typical residential use:

  • Replace all filters every 12 months
  • If incoming water is high in sediment or chlorine, replace the Sediment and Pre Carbon filters every 6-9 months
  • For use with potable municipal water supply

Angle Stop Adapter

Best for braided or flexible cold water risers.

  • Threads directly onto the cold water valve.
  • The riser nut then threads onto the top of the adapter.

.................

3/8" x 3/8" x 1/4" T Fitting

Best for rigid (plastic or metal) risers.

  • Requires cutting a 1"-1.25" section from the riser to insert the fitting.
  • Push tubing firmly into fitting until fully seated.
  • Gently pull to confirm secure installation.
  • (If installing on a metal riser, ensure cuts are clean and tubing remains perfectly round to prevent leaks).
  • Weight: 6.2 lbs
  • Dimensions: 14.5" x 11.5" x 3.5"

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