Doby OneFlow Hard Water Filter

Our Doby OneFlow whole house water filter removes scale in very hard water areas for up to 2 years.

If your water is harder than 25 grains (427 ppm CaCO3) then OneFlow may not be suitable for you. Check with your local water supplier who will be able to tell you what the hardness measurement is. 

Please note that a TDS meter may give you a higher reading but it's measuring all total dissolved solids and not just CaCO3. This is another reason to contact your local water supplier.

A highly effective limescale filter, the Doby OneFlow is a valuable additional step where you want to improve the quality of your mains or private water supply.

The Doby OneFlow hard water filter fits to your cold water supply so there's no need for a separate water filter tap.

For more technical information have a look at the Watts website.

The Doby can be fitted undersink or elsewhere, when fitting allow for a minimum of 28" (72cm) height x 12" (30cm) width x 7" (18cm) depth.

PLEASE MEASURE THE SPACE YOU HAVE AVAILABLE TO ENSURE THAT THIS MAINS WATER FILTER WILL FIT. 

Your kit will include:

• 1 x big blue 20 filter housing
• 1 x white housing bracket
• 1 x Watts OneFlow cartridge (WWQ-OF140RM)..
• Either 1/2 for 15mm or 3/4 for 22mm ports
• Isolating flexis (no need for extra ball valves)
• 1 x double check valve
• 1 x housing spanner
• Fitting instructions for your plumber. You can download the fitting instructions by clicking the link under the product image.

Cartridge details:

• WWQ-OF140RM comes as standard.
• 4.5 x 20
• Up to 4.0gpm; working life 24 months
• Certified NSF/ANSI standard 42 NSF
• Certified by ISO 9001
• Performance tested and verified by independent laboratory testing
• We send email reminders out every 6 months to remind you to think about whether you need a new Oneflow cartridge. 

Important information about TAC media

Add water to the canister containing the TAC media and leave it to stand for two hours before dropping it into the housing. If you don't do this some of the smaller particles can escape into the pipework and be lost. 

Do you have to install a mains water filter under the sink?

No, you don't. You can install your mains water filter wherever the cold water supply enters your house. This could be a utility room, garage, or other location. 

* Watts components are sometimes replaced with other similar quality items due to supply chain issues. Brassware and other plumbing accessories are sourced from UK suppliers.