UK trade guideControls & Valves 5 min readUpdated 9 July 2026

How to Fit a Mains Water Filter (UK)

Install an under-sink or whole-house water filter. Carbon, sediment and UV options. Bypass valves.

3MEverpureBWTFernox

Types by need

  • Under-sink carbon — drinking water only.
  • Whole-house 10" — sediment before combi/appliances.
  • UV lamp — well water microbiological.

Fit

Isolate incoming mains. Cut in T-piece with bypass valves either side. Fit filter housing to wall bracket.

Frequently asked questions

How often change cartridges?
Sediment 6 months, carbon 12 months, UV lamp 12 months.
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