Water filter installation costs in the UK
Before the numbers, an important caveat: we do not set installer prices and we take no cut of the work. Installers on this site charge whatever they wish and you contract with them directly. The figures below are indicative ranges for labour, gathered to help you sanity-check a quote — not a price list, and not a quotation.
Get three quotes. On the bigger jobs the spread between them is routinely wider than anyone expects.
Indicative labour costs
Labour only. Product cost is separate and varies enormously.
| Job | Typical labour | What moves it |
|---|---|---|
| Under-sink filter, existing tap hole | £120–£250 | Access, existing isolation valve |
| Under-sink filter with new tap hole | £200–£400 | Worktop material — stone costs more |
| Scale inhibitor at the boiler | £90–£200 | Often absorbed into a boiler service |
| Reverse osmosis system | £250–£500 | Drain connection and tap hole |
| Whole-house filter | £350–£800 | Stopcock access, bypass loop |
| Water softener | £400–£900 | Distance to drain, space, bypass |
| UV treatment (private supply) | £300–£700 | Usually fitted with pre-filtration |
| Commercial systems | £600–£2,500+ | Scale, premises, compliance |
| Cartridge replacement visit | £60–£150 | Most people do this themselves |
What makes a quote go up
Distance to the drain. This is the single biggest variable on a softener. A unit in the garage next to the stopcock and a gully is straightforward. A unit under a kitchen sink needing a drain run across the room is a different job.
Stopcock access. If it is behind a fitted unit, under a floor, or seized solid, everything gets harder before the actual work starts.
Worktop material. Drilling laminate is trivial. Drilling quartz is a specialist operation and some plumbers subcontract it.
Old pipework. Nobody enjoys discovering lead or badly corroded copper halfway through, and quotes for older properties price that risk in.
Making good. Ask whether the quote includes tidying up, boxing in, and taking the packaging away. It often does not.
How to compare quotes properly
Get everything in writing, itemised into labour, materials and VAT. A single number is not comparable with anything.
Ask specifically whether the price includes: isolation valves, a bypass on a softener, leaving an unsoftened drinking tap, making good, and removing the old unit if there is one. These are the items that turn a cheap quote into an expensive one afterwards.
Ask about the warranty on the workmanship as distinct from the manufacturer's warranty on the product. They are different things and only one of them is the installer's.
Check the accreditation yourself rather than taking it on trust. WaterSafe, WIAPS and TrustMark all have free public registers, and a business that is genuinely registered will not mind you looking.
Ask for proof of public liability insurance. Anyone working on your rising main should have it, and it cannot be verified from any public register — you have to ask to see the certificate.
A note on very low quotes
On a softener in particular, a quote well below the others usually means something has been left out. The commonest omissions are the bypass and the unsoftened drinking tap — both of which are things you will want, and both of which cost more to add afterwards than they would have cost to include.
Ask what is different about the cheap quote. Sometimes there is a good answer.