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How to Measure your Water Filter Tube Size

Water filter tube sizes are always measured by Outside Diameter (ie edge to edge) 

Industry-standard water filter tube sizes are:

  • 1/4 inch / 6.4mm - The most common size in the UK
  • 5/16ths inch / 8mm - This is less common. Often used by German manufacturers like Brita
  • 3/8ths inch / 9.6mm - Often used with water filters with “spigots” ie male parts at the inlet / outlet
  • 10mm - Common with American water filters
  • 12mm - Often found with water filter taps

It’s easy to find straight connectors ie to convert one size tube to the other. Checkout our Tube size combinations chart

And/or see our spare parts page (Tip: use your browser search (eg Ctrl F) to find the right part.)

Also see general info on water filter connections

This quick video show you how to measure your water filter tubing.

Drink to your health

Our water filter systems can remove harmful pathogenic bacteria, cysts, parasites, and unhealthy chemical contaminants such as Chlorine, while at the same time leaving in the essential minerals your body needs.


Save money on bottled water purchases by regularly usingfiltered water. Get your highest quality water filters at the best price here.


We supply the widest range of water filters for any needs - residential or commercial.