Mains Entry
15mm copper from the mains stopcock.
Architecture
System Architecture
This is what you are building. Every component choice below maps to one of these nodes.
1. Whole-House Pre-Filter
15mm inlet/outlet. Sediment + carbon block. Removes chlorine and particles before the conditioner. Protects the TAC media.
2. TAC Conditioner
15mm, no salt, no drain. Template Assisted Crystallisation converts Ca2+ to inert crystals. Minerals stay in the water. DVGW-tested: 99.6% scale prevention.
Kitchen Branch
All taps and shower get conditioned, mineral-retained water. Kitchen cold tee feeds the drinking filter and tap.
All taps & shower
Conditioned water, minerals retained.
3. Under-sink Drinking Filter
Frizzlife SK99-NEW. 3-stage, 0.5 micron. Minerals retained. Inline, below sink.
4. 3-Way Kitchen Tap
Hot / Cold / Filtered. Franke Omni or Quooker.
Key principle: The TAC unit goes on the mains BEFORE everything - boiler, shower, radiators, kitchen cold. The drinking filter goes on a tee from the kitchen cold (post-TAC is fine because TAC does not add anything - water exits clean and mineral-rich). The 3-way tap pulls from the drinking filter output for its filtered arm.
Recommendation Logic
Why TAC, Not a Salt Softener
Traditional ion-exchange softeners swap calcium and magnesium ions for sodium. That solves scale but removes the minerals and adds sodium to every litre - meaning you need a separate bypass for the drinking tap (or you drink sodium-dosed water). You also need a brine tank, weekly salt bags, and a drain connection for backwash regeneration.
TAC works differently. Water flows through a bed of polymer beads whose surfaces act as nucleation templates. Dissolved calcium crystallises on the bead surface into stable seed crystals (calcite), detaches, and floats harmlessly through the pipework without sticking. Scale does not form. Existing thin-film scale gradually dissolves over weeks. Nothing is removed from the water - you keep the calcium and magnesium you want for taste and health. No salt. No electricity. No drain. No bypass needed for the drinking tap.
The certification that matters: The German DVGW W512 protocol is the international benchmark for scale prevention - the same test used to approve commercial systems in hospitals and hotels across Europe. TAC media independently tested to this protocol achieves 99.6% scale prevention - equivalent to ion-exchange softening for limescale purposes, with none of the sodium load or maintenance overhead.
For PE7 8SB: Anglian Water's supply from the chalk aquifer puts Peterborough at approximately 280-300 mg/L total hardness - very hard. At this level a salt softener buys you soft skin and no scale, but costs £20-30/month in salt, 50-100 litres of wastewater per regeneration cycle, and a sodium reading in your drinking water. TAC gives the same scale protection, keeps the minerals, and the only ongoing cost is a media cartridge every 3-5 years (≈£100-200).
Component 01
Whole-House Pre-Filter
Sediment + carbon block · Protects the TAC media from chlorine and particulates
Why this comes first: Chlorine in UK mains water degrades TAC polymer bead media over time. Sediment - pipe grit, rust flakes from older copper supply - physically clogs the bead bed. A pre-filter upstream of the TAC unit extends media life from 3 years to 5+ years and is standard practice in any professional TAC installation.
Recommended: Osmio PRO-II-A Advanced Whole House Water Filter System
Two-stage system. Stage 1: Active Ceramics large filter (removes chlorine, heavy metals, fluoride, some bacteria, hormones, hormones/endocrine disruptors). Stage 2: 5-micron carbon block (chlorine, taste, VOCs). Flow rate up to 35 L/min - more than adequate for a 15mm mains supply. Dimensions: 39cm W × 21cm D × 46cm H. Filter life: ceramic cartridge 3 years / 300,000 L; carbon block 6-12 months.
15mm connection: The PRO-II-A has 1" BSP female ports. Your plumber fits 15mm → 1" BSP reducing unions on inlet and outlet - brass compression type, available at Screwfix or Toolstation for £4-6 each, two needed. Standard 10-minute job.
If space is very tight: inline twin housing (smaller footprint)
A standard 10" × 2.5" twin housing with a sediment cartridge (Stage 1, 20 micron) and a granular activated carbon block (Stage 2) does the same pre-filter job in a smaller footprint. Atlas Filtri 10" bundles run £42-62 from Pump Express UK - add £20-40 for a second housing and the two cartridges. Filter cartridges replace every 6-12 months at £10-25 each. Your plumber can source this locally as an alternative if the Osmio's 46cm height does not fit your installation point.
Osmio PRO-II-A (recommended)£352
15mm → 1" BSP reducers (×2)≈£10
Replacement carbon block (annual)£25-40/yr
Component 02
TAC Conditioner (Whole House)
Template Assisted Crystallisation · No salt · No drain · Minerals fully retained
The 15mm situation: Most UK TAC units ship with 22mm (3/4") BSP ports because 22mm is the standard mains size in newer builds. PE7 properties of Ayo's era are commonly 15mm copper from the stopcock. The options below address this: one has a native 15mm kit, the others need a pair of cheap reducers from a plumbing merchant.
Option A (Recommended) - Sullivan & White TAC 20
UK supplier, good reputation, dedicated water conditioning brand. TAC 20 (SKU: TTAC20) is sized for medium/large homes. Includes a 3-way valve with stop and bypass functions - useful for servicing without cutting off the house. TAC media tested at 99.6% effectiveness against DVGW W512 protocol. Salt-free, no electricity, no drain required.
15mm connection: Sullivan & White do not publish the port size on their product page. Call them on 01689 496848 or email info@sullivan-white.co.uk before ordering to confirm current spec and whether a 15mm fitting kit is included. If the unit ships with 22mm BSP ports, your plumber fits two 22mm→15mm compression reducing unions (Screwfix, £4-6 each). Also consider the TAC 10 at £189.99 if the property is a 2-person household - it is sized for smaller homes and may be the more cost-proportionate choice.
Option B - Scalestop Whole House with 15mm Fitting Kit
EasyH2O previously listed a “Scale Stop Whole House with 15mm Fitting Kit” - the most directly 15mm-native TAC unit found in UK search. Scalestop brand uses the same DVGW-tested TAC media at 99.6%. The 15mm fitting kit means no reducer sourcing needed. The product page returned a 404 at research time - confirm availability and current price by calling Scalestop on 01263 805355 or emailing info@scalestop.co.uk. Website: scalestop.co.uk.
Option C - HydroTAC Whole-Home System (filter + conditioner combined)
Combines TAC scale prevention and a 20-micron carbon block in one housing - effectively doing pre-filter and conditioner in a single unit. Simplifies installation where space is very tight. Flow rate 37.8 L/min. Dimensions: 229mm × 229mm × 458mm. TAC cartridge lasts up to 3 years; carbon filter annual. Connections are 1" BSP - same reducer approach as the Osmio pre-filter. If you choose this, you skip the separate Osmio pre-filter (Component 1) and install only this unit on the mains.
Trade-off: Combining stages shortens TAC media life versus having a dedicated pre-filter. A separate pre-filter + TAC unit gives longer TAC longevity. HydroTAC is the right choice only if space is the binding constraint.
Budget note: Aquabion S15 (galvanic alternative, not TAC)
The Aquabion S15 is a 15mm inline conditioner using a zinc sacrificial anode (galvanic/electrolytic technology), not TAC. Zinc ions react with dissolved calcium to form aragonite crystals that do not adhere to surfaces. Maintenance-free for up to 7 years. Body: 120mm long × 30mm diameter - extremely compact. WRAS approved. Not DVGW-certified TAC - different mechanism, different evidence base. Mentioned here as the simplest possible 15mm native fit for a plumber, but it is a budget/convenience option, not the gold-standard approach. Price varies across merchants - PlumbingSale, CentralHeat, Plumb-it all stock it; contact for current price.
Decision summary: Budget and simplicity → Sullivan & White TAC 20 (£299.99) with two cheap reducers. Want 15mm native out of the box → call Scalestop first (Option B). Tight space, one unit → HydroTAC (£499.99). Absolute minimum intervention → Aquabion S15 (but accept it is not TAC-certified).
Sullivan & White TAC 20 (recommended)£299.99
22mm → 15mm reducers (×2, if needed)≈£10
Media replacement (every 3-5 years)£100-200
Component 03
Under-Sink Drinking Filter
Frizzlife SK99-NEW · 3-stage inline · 0.5 micron · Minerals fully retained
Frizzlife SK99-NEW - confirmed pick
A 3-stage direct-connect under-sink filter. Inline design - sits on a tee from the kitchen cold supply (after the TAC unit). No dedicated filter tap needed if using a 3-way kitchen tap - the tap's filtered arm draws from the SK99 output line.
Stage 1 - M3001
Cartridge: Sediment pre-filter
Replace: Every 3-6 months
Removes: Sediment, dust, particles, rust
Stage 2 - M3002
Cartridge: Activated carbon block (0.5 µm)
Replace: Every 6-12 months
Removes: Chlorine, chloramine, lead, heavy metals, VOCs, fluoride
Stage 3 - M3003
Cartridge: Carbon post-filter
Replace: Every 12-18 months
Removes: Residual taste, odour, fine particulates
Minerals retained: The SK99 is a carbon block system - not RO. It removes contaminants but leaves calcium, magnesium, and other beneficial minerals in the water. Frizzlife explicitly states: “the SK99 doesn’t remove any of the minerals from water.” This is exactly the requirement.
Flow rate: 2.0 GPM (7.6 L/min) at 60 psi - fine for filling a glass, a jug, or a cooking pot. Certifications: NSF/ANSI 42 (aesthetic effects - taste/odour/chlorine) and 53 (health effects - lead, cysts, VOCs), certified by IAMPO.
Annual running cost: Replacement filter set M3005 (4-pack) £59.99/year from Frizzlife UK, or buy individual cartridges (£14.99-£25.99 each).
Frizzlife UK - SK99-NEW - £105.99
Amazon.co.uk listing (check current Amazon price as it may differ)
Frizzlife SK99-NEW unit£105.99
Annual replacement filter set (M3005, 4-pack)£59.99/yr
Component 04
3-Way Kitchen Tap
Hot · Cold · Filtered / Boiling - all from one fitting
The tap delivers three or four functions from a single fitting: standard hot, standard cold, and a third arm for filtered and/or boiling water. In this system, the filtered arm draws from the Frizzlife SK99 output line. Options vary on whether the third arm also delivers boiling water (100°C instant) and whether the tap has its own built-in filter.
Quooker PRO3 Fusion Round
Chrome (FNRCHR)Supply price≈£1,250
Boiling?Yes (100°C)
Chilled?No*
Filtered cold?No*
Built-in filter?HiTAC scale filter included (5yr lifespan)
Notes3-in-1: hot / cold / boiling. Add CUBE (£1,150) for filtered chilled + sparkling - total £2,400+. Includes 3L insulated boiler tank. Needs 240V 3A spur. *CUBE has its own hollow-fibre + carbon filter; if CUBE is fitted, SK99 becomes redundant for the chilled arm.
Franke Omni 4-in-1
Stainless Steel (119.0389.913)Supply price≈£999
Boiling?Yes (100°C)
Chilled?Yes (filtered chilled)
Filtered cold?Yes
Built-in filter?Built-in filter for chilled arm
NotesAll 4 functions in one tap: hot, cold, boiling, filtered chilled. Best price-to-function ratio. Built-in filter means the chilled arm does not need the SK99 - but SK99 still supplies the cold cooking-water function. Solid choice.
Zip HydroTap G5 Classic Plus
Boiling + Chilled + SparklingSupply price≈£4,500-7,500
Boiling?Yes (100°C)
Chilled?Yes
Filtered cold?Yes (0.2 µm MicroPurity)
Built-in filter?0.2 µm built-in MicroPurity filtration
NotesPremium / commercial-grade. Built-in 0.2 micron filtration makes SK99 unnecessary. SteriTouch antibacterial touchpad. Overkill for a domestic kitchen but the best-engineered option. Confirm exact model price at zipwater.co.uk as range is wide.
GROHE Blue Home Duo
e.g. 31455DC0 SupersteelSupply price≈£2,126
Boiling?No
Chilled?Yes (5-10°C chilled)
Filtered cold?Yes (still, medium, sparkling)
Built-in filter?Built-in carbon filter + CO² carbonation unit
NotesNo boiling water. Delivers chilled still/sparkling filtered water + standard hot/cold. Choose this only if sparkling water matters more than instant boiling. If boiling water is a priority, skip GROHE Blue Home.
Pick: The Franke Omni at ≈£999 is the cleanest fit for this architecture - 4 functions, best price, and you can retain the SK99 for cold cooking water even though the Omni's chilled arm has its own filter. The Quooker PRO3 at £1,250 (without CUBE) gives boiling + standard hot/cold only - the SK99 output then needs its own dedicated filter tap unless the CUBE is added, pushing the total past £2,400. If budget is not the constraint and you want sparkling water too, the Franke Omni already includes it in the chilled arm; alternatively the Zip G5 for serious premium.
GROHE Blue Home limitation: Does NOT dispense boiling water. Listed here only for completeness. If instant boiling matters to you (tea, instant noodles, blanching vegetables), do not choose GROHE Blue Home.
Price Breakdown
Total Cost Summary
All supply prices are as researched on 2026-04-24. Verify before ordering. Installation is estimated separately.
Pre-filter
Osmio PRO-II-A Advanced Whole House (2-stage)
Supply cost£352
RetailerHydrowerks
TAC conditioner
Sullivan & White TAC 20
Supply cost£299.99
RetailerSullivan & White
Fittings
BSP reducing unions ×4 (15mm→22mm or 15mm→1")
Supply cost≈£20
RetailerScrewfix / Toolstation
Drinking filter
Frizzlife SK99-NEW (3-stage, 0.5 micron, NSF certified)
Supply cost£105.99
RetailerFrizzlife UK
3-way tap (Option A - recommended)
Franke Omni 4-in-1 (hot/cold/boiling/filtered chilled)
Supply cost≈£999
RetailerAppliances Direct
3-way tap (Option B)
Quooker PRO3 Fusion Round Chrome - boiling + hot/cold only
Supply cost≈£1,250
RetailerAppliance City
Installation (estimated)
Plumber - pre-filter + TAC + tee + drinking filter + tap (≈3-4 hrs @ £50-70/hr)
Supply cost£150-280
Retailer-
Total with Franke Omni (Option A)
Pre-filter (Osmio PRO-II-A)£352
TAC conditioner (Sullivan & White TAC 20)£300
Fittings / reducers£20
Drinking filter (Frizzlife SK99-NEW)£106
Tap - Option A: Franke Omni 4-in-1£999
Installation (estimated mid-range)£200
Total with Franke Omni (Option A)≈£1,977
Total with Quooker PRO3 (Option B, no CUBE)
Pre-filter + TAC + fittings + drinking filter£778
Tap - Option B: Quooker PRO3 Fusion Round£1,250
Installation (estimated mid-range)£200
Total with Quooker PRO3 (Option B, no CUBE)≈£2,228
Annual running costs: Frizzlife replacement filter set £60/yr · Osmio carbon block replacement £25-40/yr · TAC media: zero for 3-5 years then £100-200 once. Roughly £85-100/yr in years 1-3.
Installation
Installation Order for the Plumber
Isolate water at the mains stopcock. Locate it first - typically under the kitchen sink or near the front of the property in a utility or hallway cupboard.
Identify the installation point. Fit all units as close to the mains entry as practical - ideally in a utility room, garage, or under-stair cupboard. The pipe order must be: stopcock → pre-filter → TAC conditioner → rest of house.
Cut the mains pipe and fit the pre-filter housing (Osmio PRO-II-A). Fit 15mm → 1" BSP reducing unions on inlet and outlet. Mount the housing on the wall using the included bracket. Verify flow direction matches the arrow on the housing.
Immediately downstream, fit the TAC conditioner (Sullivan & White TAC 20). Connect outlet of pre-filter to inlet of TAC unit. The TAC 20 includes a 3-way valve - set to “Filter” for normal operation; bypass position allows servicing without cutting the whole house. Fit reducers if needed.
Restore mains flow. Check for leaks at both new units before continuing. Flush for 2-3 minutes to clear debris.
Under the kitchen sink - install the drinking filter (Frizzlife SK99-NEW). Cut a tee from the kitchen cold feed (post-TAC is fine - TAC adds nothing). Run to the SK99 inlet. Connect the SK99 outlet to the 3-way tap's filtered-water inlet port using 1/4" John Guest push-fit tube.
Install the 3-way kitchen tap. Replace the existing kitchen mixer. For the Franke Omni: connect hot supply → Omni hot port, cold supply → Omni cold port, SK99 output → Omni filtered port. For the Quooker PRO3: same hot/cold connections plus the under-sink boiler tank requires a 240V 3A fused spur (1600W).
Commission. Open mains. Flush the SK99 for 5 minutes to clear carbon fines (water will run grey initially - normal for a new carbon block). Flush the filtered output at the tap. Check all connections. Confirm the boiler and all other appliances behave normally.
Label everything. Stick a label on the pre-filter and TAC unit showing installation date and next service date. Set a calendar reminder for the SK99 Stage 1 filter (3-6 months from install).
Electrical note (Quooker only): The Quooker PRO3 boiler tank requires a 240V fused spur (3A). If there is no spur near the sink cabinet, factor in an extra £80-150 for an electrician to add one.
Plumber Brief
What to Tell Your Plumber
Brief (copy-paste ready)
"I need a whole-house water treatment system fitted in series on my 15mm mains supply,
plus an under-sink drinking filter and a new kitchen tap.
The system is:
mains stopcock
→ Osmio PRO-II-A whole house filter (2-stage, wall-mounted)
→ Sullivan & White TAC 20 conditioner
→ rest of house
Both the Osmio PRO-II-A and the TAC 20 have 1" BSP (22mm) ports.
Please fit 15mm-to-1" BSP (or 15mm-to-22mm) reducing unions on inlet
and outlet of each unit. Brass compression type from Screwfix.
Under the kitchen sink:
- Fit a tee from the kitchen cold supply (post-TAC is fine)
- Run the tee to a Frizzlife SK99-NEW inline filter
- From the SK99 outlet, run 1/4" John Guest push-fit tube to
the filtered inlet port on the new kitchen tap
The kitchen tap is a [Franke Omni 4-in-1 / Quooker PRO3 Fusion Round].
It replaces the existing kitchen mixer.
[Quooker only: also needs a 240V 3A fused spur for the boiler tank
if there isn't one already near the sink.]
No salt softener involved. No drain connection needed for any of these units."
Specific fittings to have ready on the day
✓
15mm to 1" BSP (or 15mm to 22mm) brass compression reducing unions × 4 - 2 for the Osmio pre-filter, 2 for the TAC conditioner. Available at Screwfix (search “15mm 22mm reducing union”) or Toolstation. Brass preferred over plastic for a permanent mains connection.
✓
15mm compression or push-fit tee × 1 - for the kitchen cold tee to the SK99 inlet. Compression tee is better if the existing pipe is copper.
✓
1/4" OD LLDPE / John Guest push-fit tube × 1 metre - the SK99 uses 1/4" push-fit connections. Your plumber steps down from 15mm cold to 1/4" at the tee using a 15mm→1/4" JG reducing adapter (available from any water filter supplier).
✓
Quarter-turn isolating valves × 2 - one each side of the pre-filter / TAC conditioner stack. Allows either unit to be serviced without cutting the whole house. 15mm lever-type, from Screwfix.
✓
Wall-mounting bracket and fixings - the Osmio PRO-II-A includes its bracket; the TAC 20 includes its housing. Confirm both fit your wall material before job day (stud wall vs. masonry makes a difference to fixings needed).
Questions to ask the plumber when quoting
?
Can you confirm the mains entry pipe is 15mm copper at the stopcock, or is any section already 22mm? (Determines whether reducers are actually needed.)
?
Is there a suitable location for two inline units near the stopcock - minimum approximately 60cm of wall space vertically?
?
If Quooker: Is there an existing 3A fused spur or switched fused spur within reach of the sink cabinet? If not, can you add one, and at what cost?
?
Can you source the reducing unions locally, or should I have them ready?
?
Have you fitted a TAC or scale prevention unit before? (If not, ask Sullivan & White to email an installation PDF before the job: info@sullivan-white.co.uk)
Building Regulations / WRAS: None of these units require a building control notification under Part G. The TAC conditioner and pre-filter are standard inline fittings. A kitchen boiling tap (if Quooker or Franke Omni) is a standard consumer appliance - it needs a WRAS-compliant water connection and a safe electrical spur, both within a competent plumber and electrician's normal scope.
Time estimate: A plumber who has fitted TAC units before will complete the pre-filter + TAC section in 1-1.5 hours. The under-sink drinking filter + new tap adds another 1-2 hours. Budget 3-4 hours total. If first time fitting a TAC unit, allow 4 hours to be safe.