Large selection of replacement water filters, reverse osmosis membranes, testing kits and water filter system repair parts. From one water filter or membrane to case quantity discounts.

LOW PRICES and FAST SHIPPING SINCE 1999 !

99.5% Of All Items In Stock For Same Day Shipping!

Flow Restrictors

Flow Restrictors

Flow Restrictors For Reverse Osmosis Pure Water Systems

 Flow Restrictors (aka) Flow Controls or Capillaries) are required for all reverse osmosis systems. The Flow Restrictor must be matched in sized to the RO membrane GPD capacity. Flow Restrictors work with the incoming water pressure to power the ASV (auto shut-off valve) and apply the proper pressure throughout the reverse osmosis sytem.  Matching the GPD to ml/min (milliliters per minute) flow rate of the flow restrictor will maintain the correct ratio of reject flow (to drain) and permeate (product) flow.

It is recommended that you replace the Flow Restrictor each time you replace your reverse osmosis membrane to keep your system operating at peak efficiency. The number on the flow restrictor indicates the flow rate, in milliliters per minute. The flow restrictor should match your reverse osmosis membrane's GPD (gallons per day) production rate. 

Inline Flow Restrictors Are Recommended - Inline Flow restrictors are very easy to install. They are installed in the 1/4" drain line between the system and the drain saddle.  Our inline flow restrictors use quick connectors for simple installation.   

The following table gives a guideline for selecting the correct inline flow restrictor for your RO membrane.

RO Membrane Size
(Gallons Per Day)
Use Flow Restrictor
(ML Per Minute)
8-20 GPD 150
21-25 GPD 250
36 GPD 350
50 GPD 500
75 GPD 750
100 GPD 1000
150 GPD 1200

 

inline reverse osmosis flow restrictor


The insert style of flow restrictor is a small plastic insert that fits inside of the waste water (brine) outlet on the RO membrane housing or inside of the tube at the connection with the membrane housing. You will need to remove the tube and look inside of the fitting to see the "Insert" if it is in the connector fitting. If it is in the end of the tube, you can see it by removing the tube from the connector. 


Learn How To How to Increase the Gallons Per Day (GPD) of your RO System.

 

 

Learn How To How to Increase the Gallons Per Day (GPD) of your RO System. This will ensure water is available at busy times of the day and also ensure adequate flow to the ice maker. If the ice maker does not have enough flow, it can burn out. The reverse osmosis membrane upgrade is simple on most reverse osmosis systems.

  1. Flow_Restrictor-1000
    FLOW RESTRICTOR - INLINE - 150 ML 1/4' QUICK CONNECT FITTINGS
    150 ml Premium inline reverse osmosis membrane flow restrictor - Our in-line capillary flow restrictors are simple to install. Simply push the 1/4" poly tube firmly into the quick connectors and you are done. Be sure that you order the flow restrictor size to match your reverse osmosis membrane size. Arrow on side points toward the drain. Very simple to install.
    Learn More
    $33.99 Special Price $19.99 As low as $14.99
  2. Flow_Restrictor-250-1000
    Flow Restrictor - Inline - 250 ml 1/4' quick connect fittings

    Flow Restrictor - capillary - 250 ml 1/4" quick connect fittings. 

    Premium inline reverse osmosis membrane flow restrictor - Our in-line capillary flow restrictors are simple to install. Simply push the 1/4" poly tube firmly into the quick connectors and you are done. Be sure that you order the flow restrictor size to match your reverse osmosis membrane size. Arrow on side points toward the drain. Very simple to install.

    Learn More
    $19.99
  3. Flow_Restrictor-350 (Flow Restrictor - capillary - 350 ml  1/4' quick connect fit-1000
    Flow Restrictor - Inline - 350 ml 1/4' quick connect fittings

    Flow Restrictor - capillary - 350 ml 1/4" quick connect fittings. 

    Premium inline reverse osmosis membrane flow restrictor - Our in-line capillary flow restrictors are simple to install. Simply push the 1/4" poly tube firmly into the quick connectors and you are done. Be sure that you order the flow restrictor size to match your reverse osmosis membrane size. Arrow on side points toward the drain. Very simple to install.

    Learn More
    $19.99
  4. Flow_Restrictor-500  Flow Restrictor - capillary - 500 ml  1/4' quick connect fit-1000
    Flow Restrictor - Inline - 500 ml 1/4' quick connect fit...

    Flow Restrictor - capillary - 500 ml 1/4" quick connect fittings. 

    Premium inline reverse osmosis membrane flow restrictor - Our in-line capillary flow restrictors are simple to install. Simply push the 1/4" poly tube firmly into the quick connectors and you are done. Be sure that you order the flow restrictor size to match your reverse osmosis membrane size. Arrow on side points toward the drain. Very simple to install.

    Learn More
    $19.99
  5. Flow_Restrictor-750 (Flow Restrictor - capillary - 750 ml  1/4' quick connect fit-1000
    Flow Restrictor - Inline - 750 ml 1/4' quick connect fittings

    Flow Restrictor - capillary - 750 ml 1/4" quick connect fittings. 

    Premium inline reverse osmosis membrane flow restrictor - Our in-line capillary flow restrictors are simple to install. Simply push the 1/4" poly tube firmly into the quick connectors and you are done. Be sure that you order the flow restrictor size to match your reverse osmosis membrane size. Arrow on side points toward the drain. Very simple to install.

    Learn More
    $19.99
  6. Flow_Restrictor-1000 (Flow Restrictor - capillary - 1000 ml  1/4' quick connect -1000
    Flow Restrictor - Inline - 1000 ml 1/4' quick connectors

    Flow Restrictor - capillary - 1000 ml 1/4" quick connect fittings. 

    Premium inline reverse osmosis membrane flow restrictor - Our in-line capillary flow restrictors are simple to install. Simply push the 1/4" poly tube firmly into the quick connectors and you are done. Be sure that you order the flow restrictor size to match your reverse osmosis membrane size. Arrow on side points toward the drain. Very simple to install.

    Learn More
    $19.99
  7. Flow_Restrictor-1000
    Flow Restrictor - Inline - 1200 ml 1/4' quick connector

    Flow Restrictor - capillary - 1200 ml 1/4" quick connect fittings. 

    Premium inline reverse osmosis membrane flow restrictor - Our in-line capillary flow restrictors are simple to install. Simply push the 1/4" poly tube firmly into the quick connectors and you are done. Be sure that you order the flow restrictor size to match your reverse osmosis membrane size. Arrow on side points toward the drain. Very simple to install.

    Learn More
    $19.99
  8. Hydrotech 25 GPD RO Reverse Osmosis System Capillary Flow Restrictor #40600040
    Hydrotech 25 GPD RO Reverse Osmosis System Capillary Flow Restrictor #40600040

    Hydrotech 25 GPD RO Reverse Osmosis System Capillary Flow Restrictor Tube #40600040.

    RED DRAIN LINE 25 GPD RO, TUBE WITH FLOW RESTRICTOR (1230/1240 SERIES)

    Learn More
    $19.99
  9. Stainless Steel Insert Flow Restrictor with Stainless Steel Sediment Screen- 350 ml or 500 ml
    Stainless Steel Insert Flow Restrictor with Stainless Steel Sediment Screen- 350 ml or 500 ml

    Stainless Steel Insert Flow Restrictor with Stainless Steel Sediment Screen- 350 ml or 500 ml

    Stainless Steel Insert Flow Restrictor with SS Sediment Screen

    Learn More
    $36.99 Special Price $19.99 As low as $12.63
  10. John Guest ® Tube Cutter - TSNIP
    John Guest ® Tube Cutter - TSNIP
    John Guest ® tube cutter TSNIP - Great for making a perfect cut everytime. Helps prevent leaks by making a square end cut ensuring proper fit and seal in water connecttion fittings. A real must for any professional or discerning home owner.
    Learn More
    $17.99 Special Price $12.99 As low as $10.99
  11. Drain Saddles For Reverse Osmosis RO Water Systems
    Drain Saddles For Reverse Osmosis Systems
    Drain Saddles For Reverse Osmosis Systems - Connects reverse osmosis system drain tube to sinks drain pipe. Standard size drain saddle is 1/4". 3/8" Drain Saddle typically used in conjunction with optional air gap faucet.
    Learn More
    $9.99 Special Price $6.99 As low as $0.00
  12. Standard Size RO Reverse Osmosis Membrane Housing
    Standard size RO reverse osmosis membrane housing
    Standard size RO reverse osmosis membrane housing - 90° Ports with 1/8" FNPT Threads - Includes New O-rings and 3 90° 1/4" Jaco Fittings For 1/4" O.D. Tube. Upgrade to the optional John Guest Quick Connectors. The end with a single port is the inlet feed water. On the end with two ports the center port is the permeate (product) water. The offset port is the brine (waste).
    Learn More
    $34.99 Special Price $19.99 As low as $16.99

Easy TDS Membrane Performance Calculator
See If It is Time To Replace Your Membrane

Simply enter your Feed Water TDS and RO Water TDS into the boxes above and click "Submit". The percentage of TDS Rejection will be displayed. We normally recommend membrane replacement once you drop below 75%. This may vary in areas with high TDS in the feed water.

See our selection of TDS meters under Water Tests

Be sure to check our Parts Department for important parts such as TDS Testers For Reverse Osmosis Membranes, Replacement Tanks, O-rings , Filter Housing Wrenches, Faucets, Pumps, Fittings, UV Systems and more parts for your reverse osmosis pure water filtration system.   View maintenance and servicing tips online at our Installation & Trouble shooting Guide.