Under-Sink vs Whole-House Water Filters: Which to Choose?

Puretec whole house filter delivering filtered water to every tap

An under-sink filter treats water at one tap – usually the kitchen – for drinking and cooking. A whole-house filter is installed where the water supply enters your home and treats all of it, so every tap, the shower and your appliances get filtered water. Many households combine both: a whole-house system for general protection and an under-sink filter for extra treatment of drinking water.

At a glance

Under-sinkWhole-house
Taps coveredOne tapEvery tap and shower
Shower water filteredNoYes
Appliance protectionNoYes – hot water systems, washing machines, dishwashers
LocationUnder the kitchen benchOutside wall, fence, in-wall cabinet or near the tank
Typical Puretec systemsPureMix Z2, Z6, Z7; RO270; Hybrid M1FilterWall F series, WH2, FilterWall IM2; Hybrid E for rainwater

Why choose whole-house filtration?

Puretec explains that a whole-house system not only delivers filtered drinking water to every tap by reducing sediment and chemicals like chlorine, but also acts as a defence for appliances. It helps protect hot water systems, washing machines, dishwashers, pipes and tapware from the corrosive effects of chlorine and blockages caused by sediment. Because your shower water is filtered, Puretec notes it helps protect skin and hair from chlorine, a common cause of skin and scalp irritation, dryness and itching.

Options include the FilterWall F5 freestanding 3-stage system, the WH2-55 wall-mounted dual system and, for new builds, the semi-recessed FilterWall IM2. Choose a model to suit your home’s size and flow rate.

Why choose an under-sink filter?

  • Targeted drinking water treatment. Puretec’s PureMix Z series connects to your existing mixer tap, so there’s no need for a second tap.
  • Compact options. The PureMix Z2 is designed for limited under-sink space, such as bathrooms, laundries, caravans and kitchenettes.
  • Specialist treatment. Reverse osmosis (RO270) for fluoride or nitrate is a point-of-use system.
  • DIY cartridge changes. Quick-twist valve-in-head cartridges can be changed without turning off the water.

Combining both

Puretec’s PFAS guidance is a good example: a whole-house FilterWall F5 gives good coverage, and adding an under-sink PureMix Z7 gives the drinking water further exposure to carbon. Puretec also describes the PureMix Z7 as particularly effective as a secondary filter after a whole-house system.

Rainwater homes

For rainwater, the same choice applies: the Hybrid E series treats the whole house with filtration and UV, while the Hybrid M1 treats one tap. For Cryptosporidium, Puretec says a whole-house system is the primary choice because single-tap systems don’t protect shower water.

Installation: connection to your water supply must be carried out by a licensed plumber, and any hard-wired electrical work by a licensed electrician.

Recommended products

Frequently asked questions

Does a whole-house filter provide filtered drinking water?

Yes. Puretec explains a whole-house system delivers filtered water to every tap by reducing sediment and chemicals like chlorine. Some households add an under-sink filter for extra treatment at the kitchen tap.

Can I install a whole-house filter myself?

No. Connection to your water supply must be carried out by a licensed plumber, and any hard-wired electrical work by a licensed electrician.

How do I size a whole-house filter?

Puretec matches models to home size and flow – for example WH2-30 for 1 to 2 bathrooms and WH2-55 for 2+ bathrooms, and FilterWall F3/F4 for small to medium homes and F5/F6 for 2+ bathrooms.

Do I need both?

Not always. A whole-house filter suits most mains water taste and chlorine concerns. Adding an under-sink filter makes sense if you want extra treatment of drinking water, such as for PFAS, fluoride or nitrate.

Related guides: Which water filter do I need?, Chlorine taste and smell, PFAS in tap water.

Questions? Call or text 0447 203 775 or email [email protected] and we will help you choose.

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