The Harvey TwinTec Series 4 Water Softener. 2 years Replacement & 10 Years Parts Warranty - regardless of your installer.

Harvey Water Softener Discount Code. Buy the Harvey TwinTec S4 now for only £1124.99.

Use code: HARVEY to save an extra £25 off. Shop the Best Water Softener UK of 2024.

Please note - salt is sent separately from the water softener and therefore will arrive at different times. Salt delivery can take up to 7-10 days.

Get Free Delivery on all Harvey Water Softeners

Found the Harvey TwinTec Series 4 for a cheaper price online? We have a price match guarantee & pride ourselves on giving you the best price. We now also have buy now pay later options available.

We provide a 2 year labour and 10 year parts warranty.

As an exclusive & verified #1 Harvey online dealer our warranty is valid - regardless of your installer. Have a plumber install your system and save up to £600 off installation packages. Need help finding a plumber for your installation? Talk to us today on 02031486773 or view our referral list.

Is a Harvey Water Softener worth the money?

The Harvey Twintec S4 is a twin tank water softener from the UK's most trusted brand - Harvey Water Softener. Once installed this product will remove hard water and limescale from your entire home and is designed to last 10-20 years.

You Should Buy the TwinTec S4 if...

• You have a property with 3 or 4 bathrooms or have a family of 3-8 people.
• You have limed space underneath your kitchen sink.
• You are looking for a softener that will last 10-20 years.
• You need to remove hard water & limescale from your home.

Harvey Water Softener Comparison

The Harvey MiniMax Vs Harvey TwinTec S4 

When Comparing the Harvey TwinTec S4 to other water softeners such as the Harvey MiniMax and the Harvey Arc - you'll find the same technical specifications such as flow rate, pressure and efficiency. The Harvey MiniMax water softener is identical to the TwinTec S4 but is sold by different distributors. The Harvey Arc water softener is very similar to the TwinTec S4 and can only be purchased through Harvey direct. Of all models - get the best value for money with the Harvey TwinTec S4. Find out more in this Harvey Water Softener comparison. 

 exact same specification as the Harvey Ac water softener.

The Harvey Crown Water Softener Vs the TwinTec S4

When shopping for a water softener it's important to ensure you get the best value for money - and that means comparing specification, warranty and efficiency/running costs. When comparing the Harvey Crown and TwinTec water softener - you'll find big differences in efficiency, flow rate and the technology used. You an find out more in our Harvey Crown comparison. With the TwinTec model you'll get:

• A 40% higher flow rate and performance - meaning no pressure loss.
• 26% increase in water efficiency - 26% less water used during regeneration.
• 15% increase in salt efficiency and 15% less salt used.
• Lower running costs overall.
• A 10 year warranty & guarantee vs only 1-5 years for the crown water softener.
• A water softener that lasts longer, uses the latest technology & costs less to run.

Harvey Vs Kinetico Water Softeners

The Harvey Vs Kinetico debate is a popular one across water softener consumers - which brand is best? Both brands sell similar products but Harvey give you the best value for money with the best prices available. You can see a comparison here.

How Much is a Harvey Water Softener? Harvey Water Softener Price

How much are Harvey Water Softeners? Harvey Water Softener prices generally depends on a few things including the model you're purchasing, warranty and the retailer. The TwinTec S4 water softener comes with a 10 year warranty and has one of the best domestic water softener specifications available. With an RRP of £1450, right now our systems are on sale for £1124.99 - meaning you'll get the best quality product available at the best harvey water softener price. Don't pay more than you have to. We now also have a buy now pay later option available to help spread the Harvey water softener cost.

Harvey Water Softener Discount Code

Save money off with a Harvey water softener discount code. For the TwinTec S4, use the discount code HARVEY at checkout.

TwinTec Series 4 Specification

Click here to view the Harvey S4 Brochure PDF 

Key Features:

• Small & Compact Size: the smallest twin tank softener that fits easily underneath your kitchen sink.
• Twin Tank Design: designed to deliver soft water 24/7.
• Non-Electric & Automatic: no timers or controls needed.
• A 2 year replacement and 10 year parts warranty by NEWS: the S4 has a 10-year warranty for parts and a 2 year replacement warranty.
• A Patented Metering System: allowing the softener to measure water usage very accurately – down to measuring two drips per second.
• A Nano Technology Ultra Fine Resin: the patented resin of the S4 uses a unique ultra-fine exchange resin for higher flow rates and greater exchange capacity.
• Smart Shuttle Metering for Pressure Adaptations: a smart shuttle meter for all different pressure systems including gravity-fed systems, tanks in the loft, combination boilers and high flow  cylinders.
• High Flow Rate: with a max flow rate of 56 litres per minute, power showers and mega flows are no problem.
• Great Efficiency: Uses only 300g of salt per regeneration which requires only 17L of water and takes just 11 minutes.
• Tried & Tested Durability: these TwinTec designs are tried and tested for maximum durability & reliability.
• Uses Block Salt- the reverse osmosis system is powered by a brine solution.

How does the home attendance labour warranty work?

When you purchase your system through us, you benefit from comprehensive warranty coverage: 2 years of on-site (home attendance) labour support and a generous 10-year parts warranty.

Here’s how it works: In some cases, if there is a clear fault with your system in the first year we will arrange a pick up of your old unit and send you a brand new one - without a home visit being necessary. In other cases where your water softener develops a fault during the first two years and this fault is harder to diagnose over the phone, a qualified manufacturer service technician will visit your home, diagnose the issue, and carry out the necessary repairs—or if needed, replace the unit—right then and there. There’s no hassle of being referred to an unfamiliar third-party or local tradesperson; your warranty service is managed directly by the manufacturer’s own experts, ensuring reliable support and a quick resolution.

This home attendance warranty covers most types of faults, from operational issues to repairs involving key components. And remember, this applies to systems located within covered London postcodes. Want to check if your address qualifies? Head over to our postcode coverage page or ring us at 02031486773—we’re always happy to help clarify your coverage and point you in the right direction.

Why Choose a Manufacturer’s Service Team for Warranty Repairs?

Being a part of Harvey Water Softeners, we have access to a direct service team. Opting for our warranty and service team brings peace of mind you simply can’t get with a random local plumber. Here’s why our customers love this approach:

• Expert Care: The manufacturer’s technicians work exclusively with your model day in, day out. They know exactly what to look for and how to fix it right the first time.
• Efficient Resolution: No third-party back-and-forth. The team arrives with the right tools and original parts, aiming to repair or replace in just one visit.
• Genuine Parts: With us -all repairs come from Harvey Technicians and use only genuine Harvey components, ensuring your system’s performance and longevity.
• Consistency: It’s the same trained team attending across London, so you receive a reliable, consistent level of service every time.

In short, you get swift, specialist attention that maximises your Harvey softener’s lifespan—without surprises.

Water Softener Installation

A water softener is installed next to the stop tap, which is usually underneath the kitchen sink. This can be easily carried out by a plumber and you will usually require an installation kit. We offer installations in select areas in the UK, we also have a list of plumber referrals that can help! Need help finding a plumber for your installation? Talk to us today on 02031486773 or view our referral list.

For Installation Manual Click Here

How Does the Design of the Water Softener Make it Easy to See When Salt Needs to Be Refilled?

This model has a clear lid encompassed within the cabinet which makes it easy to see your salt blocks and see when they are running low.

What household size is this Twin Tec Water Softener designed for?

This Twin Tec Water Softener comfortably meets the needs of households ranging from single occupants up to larger families, typically accommodating anywhere from 1 to 10 people. If your home has particularly high water usage or you need even more capacity, an upgraded version is available to handle bigger demands.

Why Choose a Twin-Cylinder Water Softener Over a Single-Cylinder?

When it comes to water softeners, the difference between a twin-cylinder system and a single-cylinder setup is night and day—especially for busy households.

Here’s why a twin-cylinder water softener is the smarter choice:

• Continuous Soft Water, 24/7
  Twin-cylinder systems—like those found in high-end Kinetico and Harvey units—work with two cylinders that operate independently. While one cylinder is regenerating, the other keeps providing soft water. That means you’ll never face a cold shower or disruptions, no matter how much water you’re using or what time it is.

• No Downtime for Regeneration
  Single-cylinder models shut off during the regeneration process, leaving you stuck with untreated hard water for periods of time. With a twin-cylinder design, regeneration happens behind the scenes—no interruptions, no waiting.

• Perfect for Larger Families or High Water Usage
  If you’ve got a bustling household, guests, or several bathrooms (think: morning rush hour), twin-cylinder softeners ensure you never run out of soft water—unlike many entry-level alternatives.
  

In short, if you want hassle-free, seamless soft water with the highest efficiency, a twin-cylinder system easily outperforms single-cylinder options—especially those from brands like Kinetico and other leading manufacturers.

What Salt Does the TwinTec Use, and How Do You Refill It?

The TwinTec Series 4 model  is designed to use block salt, which is not only simple to store but also a breeze to handle—no more wrestling with heavy, messy salt bags! Refilling is refreshingly straightforward: just lift the clear lid, check the easy-to-see red level indicator, and pop in new salt blocks when needed. The block salt system is created specifically for maximum efficiency, so your softener only regenerates when required, rather than running on an unnecessary daily schedule. This approach keeps your softener running smoothly—and your life hassle-free.

The Benefits of Using Block Salt Technology 

If you have never had a water softener before - salt based systems are the only real way to remove hard water. Anything that claims to be "saltless" will not be able to remove the hard water ions from your water.

If you've previously had a system that uses tablet salt - switching to block salt is one of those small upgrades that has a surprisingly big impact. If you've struggled with lugging around heavy, messy bags of loose salt, you'll instantly appreciate the convenience factor here. Block salt is designed to be hassle-free—think tidy storage and quick refills, no more salt spills across the kitchen floor.

But the benefits don’t end at convenience. The S4 system is tailored to make each block of salt go further, only regenerating when absolutely necessary—unlike traditional models that run on daily timers and waste more salt. This smart approach means you get more out of each refill, keeping running costs down.

Plus, checking salt levels is refreshingly simple. Thanks to a clear lid and an easy-to-spot indicator line, you’ll always know exactly when it’s time to top up. It's a practical, no-fuss solution that keeps your system running smoothly and your routine uninterrupted.

How Does the TwinTec Work Without Electricity?

One of the clever things about this Harvey Water Softener model is that it doesn't rely on mains electricity at all. Instead, it uses the natural flow and pressure of your incoming water supply to drive the entire softening process. So, if there's ever a power cut, your water softener keeps ticking along perfectly—no wires, plugs, or panic needed.

There are no fiddly settings, timers, or digital displays to worry about either. Just fit it, and forget it. The regeneration cycle—the process where the softener refreshes itself—only kicks in when it's actually needed (measured precisely by how much water you use). This means it won’t waste water by regenerating when you’re away or while the house sits empty for the day.

The result? A hassle-free, energy-efficient system that quietly does its job in the background for you, with no buttons to press or maintenance routines to remember.

How Does the Twin Cylinder Technology in this Water Softener Provides Continuous Softened Water?

Continuous Soft Water—No Waiting Around

• 24/7 Soft Water Supply: Thanks to its clever twin tank system, this softener doesn’t take a break—even when it’s regenerating. While one tank is busy cleaning itself, the other keeps on delivering soft water to your taps.
• Uninterrupted Performance: Unlike traditional single-tank models like those from Water2Buy or BWT , which pause service during regeneration cycles, this setup ensures you’re never left in the lurch. You enjoy a constant flow of luxuriously soft water, day or night, even during those marathon family showers.

How Does TwinTec Series 4 Decide When to Regenerate?

One of the standout features of the TwinTec Series 4 is its smart metering system. Instead of running on a fixed schedule, this water softener only regenerates when needed. It keeps track of exactly how much water your household is using—right down to just a couple of drips per second. So, if you’re away on holiday or just not using much water, the system simply waits. No unnecessary cycles, no wasted water.

This clever approach means the S4 only uses water for regeneration when it’s truly required, making it much more efficient than older, timer-based models. Not only does this save on water and salt, but it also ensures your softener is always ready to deliver perfectly softened water when you need it most.

Recommended Accessories for Your Harvey Water Softener

To keep your Harvey water softener performing at its best, a few additional products are worth having on hand:

• Block Salt Packs: You'll need block salt to keep your water softener running smoothly. These are supplied in convenient packs—purchase in bulk to save on costs and reduce the number of reorders.
• Installation Kits: It's important to match the correct installation kit to your plumbing. Installation kits typically come in 15mm or 22mm sizes to suit most UK pipework. Including high-quality connectors and fittings, these kits ensure a simple, hassle-free setup.
• Pressure Reducing Valve: In few cases, if the home's water pressure is too high, a pressure reducing valve may be necessary.
• Upgrade Options: For homes with higher demand or specific installation requirements (such as larger homes or properties with high water usage), consider additional accessories or larger models.

By preparing with these recommended items, you’ll ensure a smooth installation process and ongoing reliability for your Harvey system.

Prices for Block Salt & Installation Kits

If you’re budgeting for your water softener purchase, it’s helpful to know the prices of related essentials like block salt and installation kits:

• Block Salt (9 Pack - 18 blocks): Is around £75, with each home using on average 1 block per person per month. This keeps your system running smoothly and ensures you’re always stocked up.
• Water Softener Installation Kits:
  • 15mm Kit: These standard-size kits are typically available for £110, providing everything you need for a professional-quality installation on standard pipework.
  • 28mm (1 inch) Kit: If you have larger pipework, a 28mm installation kit will run about £189.99. These are ideal for homes with higher flow requirements or larger plumbing setups.

Keep these extras in mind when planning your initial investment—a quality installation kit and a supply of block salt will make setup effortless and maintenance simple.

How Easy is the TwinTec Water Softener to Install and Operate?

Wondering how straightforward it is to get started with your new water softener? The installation process couldn’t be easier—since the system runs entirely on your home’s water pressure, there’s no need to worry about finding a nearby power socket or any tricky wiring. That means you have plenty of flexibility when choosing an installation spot.

Once fitted, ongoing use is refreshingly hands-off. There are no fiddly dials, settings, or digital displays to adjust—just set it up and let it quietly look after itself. No need to reset clocks after a power cut or monitor timers. It’s designed for hassle-free operation, making it ideal if you’re after convenience and simplicity in your daily routine.

WRAS Approval

This water softener is fully approved by the UK Water Regulations Advisory Scheme WRAS, ensuring it meets the highest UK water safety standards. You can have confidence that it complies with all relevant regulations for installation and operation within your home.

Where is this water softener engineered and manufactured?

A UK Water Softener - Proudly Crafted in the UK 

Wondering where your new Harvey TwinTec S4 water softener comes from? Rest assured—this system is expertly engineered and built right here in the UK. With nearly four decades of British manufacturing expertise behind it, the TwinTec S4 is made to meet the needs of UK homes and plumbing standards perfectly. That means you’re getting a water softener designed for reliability, efficiency, and a seamless fit under your kitchen sink—no awkward adjustments or guesswork required.