A softener costs £466.66–£655 for the unit (from 3 UK listings checked October 2026) or £800–£2,000 supplied and fitted (from 3 UK listings checked October 2026). Running one costs mostly salt: see the table by household size below.
Softener unit only (you arrange fitting)
£466.66–£655
from 3 UK listings checked October 2026
- Plumb2U · price checked 13 October 2026: Monarch Master HE Water Softener inc. Kit, £655.00
- Plumb2U · price checked 13 October 2026: Tapworks 11L Water Softener including installation kit, £466.66
- Wickes · price checked 13 October 2026: BWT WS355 Standard Water Softener, £610
Supplied and fitted
£800–£2,000
from 3 UK listings checked October 2026
All 3 prices are packages from one installer, C A Waters Plumbing & Heating, so treat this as one firm's price list rather than a national range.
- C A Waters Plumbing & Heating · price checked 13 October 2026: Harvey Compact, £800–£1,200
- C A Waters Plumbing & Heating · price checked 13 October 2026: Kinetico Twin, £1,200–£2,000
- C A Waters Plumbing & Heating · price checked 13 October 2026: BWT Electric, £800–£1,400
Prices as listed, including VAT. Observed advertised listings, not a UK market average or binding quote. Counts refer to listings; the installed packages come from one Hertfordshire installer. Preserve each listing's availability and survey conditions when displaying the range.
Every price we checked
Each price is the listing as we read it on 13 October 2026, including VAT. We don't convert US prices or estimate one we haven't seen.
Monarch Master HE Water Softener inc. Kit: £655.00
Unit and installation kit; fitting labour not included. Catalogue listing; stock requires branch check.
Plumb2U · price checked 13 October 2026
Tapworks 11L Water Softener including installation kit: £466.66
Unit and installation kit; fitting labour not included. Catalogue listing; stock requires branch check.
Plumb2U · price checked 13 October 2026
BWT WS355 Standard Water Softener: £610
Unit with 15mm fitting kit; delivery and fitting labour excluded. Advertised price, currently out of stock.
Wickes · price checked 13 October 2026
Harvey Compact: £800–£1,200
Installer package label, exact manufacturer model not specified. Includes VAT, unit, bypass valve, pipework, drain connection and commissioning in Hertfordshire; subject to survey; complex installations quoted separately.
C A Waters Plumbing & Heating · price checked 13 October 2026
Kinetico Twin: £1,200–£2,000
Installer package label, exact manufacturer model not specified. Includes VAT, unit, bypass valve, pipework, drain connection and commissioning in Hertfordshire; subject to survey; complex installations quoted separately.
C A Waters Plumbing & Heating · price checked 13 October 2026
BWT Electric: £800–£1,400
Installer package label, exact manufacturer model not specified. Includes VAT, unit, bypass valve, pipework, drain connection and commissioning in Hertfordshire; subject to survey; complex installations quoted separately.
C A Waters Plumbing & Heating · price checked 13 October 2026
Running costs by home size
| People in your home | Moderately hard (150–200) | Hard (200–300) | Very hard (more than 300) |
|---|---|---|---|
| 1 person | Moderately hard:£16–£22 a year (20 kg/year–28 kg/year of salt) | Hard:£21–£33 a year (27 kg/year–41 kg/year of salt) | Very hard:at least £32 a year (at least 40 kg/year of salt) |
| 2 people | Moderately hard:£32–£44 a year (40 kg/year–55 kg/year of salt) | Hard:£43–£65 a year (54 kg/year–82 kg/year of salt) | Very hard:at least £64 a year (at least 81 kg/year of salt) |
| 3 people | Moderately hard:£48–£65 a year (60 kg/year–82 kg/year of salt) | Hard:£64–£98 a year (81 kg/year–122 kg/year of salt) | Very hard:at least £97 a year (at least 121 kg/year of salt) |
| 4 people | Moderately hard:£64–£87 a year (81 kg/year–109 kg/year of salt) | Hard:£86–£130 a year (108 kg/year–163 kg/year of salt) | Very hard:at least £129 a year (at least 162 kg/year of salt) |
| 5 people | Moderately hard:£81–£109 a year (101 kg/year–136 kg/year of salt) | Hard:£108–£163 a year (135 kg/year–203 kg/year of salt) | Very hard:at least £162 a year (at least 202 kg/year of salt) |
Salt only: electricity, regeneration water, servicing and delivery are not included. Worked for the BWT Aquadial Softlife 15 (15 / 15 Bio), nominal full regeneration using 142 litres per person per day (Energy Saving Trust), 767.464 g of hardness (as CaCO₃) per regeneration (BWT UK), 2 kg (BWT UK), £0.80 per kg (Wickes). A band's range runs from its lower to its upper edge; the top band has no upper edge, so its figure is a minimum.
We don't estimate savings or payback: no independent figure for what a softener saves a UK household is admitted in our sources, and installer claims are not evidence.
Do you need one at all?
Only hard and very hard water make a softener clearly worth it. Check your postcode's band first.
Check your postcode's hardness band
Related guides
Frequently asked questions
- How much does a water softener cost in the UK?
- Softener units cost £466.66–£655 including VAT before fitting (from 3 UK listings checked October 2026). Supplied and fitted, £800–£2,000 (from 3 UK listings checked October 2026). All 3 prices are packages from one installer, C A Waters Plumbing & Heating, so treat this as one firm's price list rather than a national range.
- How much does it cost to run a water softener?
- Mostly salt. The running-cost table on this page gives the salt cost per year by household size and hardness band; electricity, servicing and delivery are extra.
- Does a water softener pay for itself?
- We don't estimate payback: we have no independent figure for what a softener saves a UK household, and installer claims are not evidence.
Sources
- Energy Saving Trust ↗ · At Home with Water, July 2013, p. 8 (PDF page 8) · No open reuse licence identified; factual transcription and short citation excerpt only. · read 13 October 2026
- BWT UK ↗ · BWT-GD 03-50001 / Rev. 1.02 - EN / 2012-01, p. 2 · No open reuse licence identified; factual transcription and short citation excerpt only. · read 13 October 2026
- Drinking Water Inspectorate ↗ · Undated consumer page, Table 1; checked 13 October 2026 · Open Government Licence v3.0 (page footer). · read 13 October 2026
- Wickes ↗ · Live retail listing checked 13 October 2026; single bag, excluding delivery · No open reuse licence identified; factual transcription and short citation excerpt only. · read 13 October 2026
- Wickes ↗ · Terms and Conditions, Price and Payment; checked 13 October 2026 · No open reuse licence identified; factual transcription and short citation excerpt only. · read 13 October 2026
- Plumb2U ↗ · Live VAT-inclusive catalogue checked 13 October 2026 · No open reuse licence identified; factual transcription and short citation excerpt only. · read 13 October 2026
- Wickes ↗ · Live retail listing checked 13 October 2026; out of stock · No open reuse licence identified; factual transcription and short citation excerpt only. · read 13 October 2026
- C A Waters Plumbing & Heating ↗ · Undated installer packages, checked 13 October 2026; Hertfordshire, subject to survey · No open reuse licence identified; factual transcription and short citation excerpt only. · read 13 October 2026
Contains public sector information licensed under the Open Government Licence v3.0