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Water Softeners

TwinTec S4 Water Softener

Non-Electric Twin-Cylinder System · Suitable for 1–3 Bathrooms · 10 Year Warranty

Key Features

Twin-Cylinder Design

24/7 softened water with no interruptions during regeneration

Non-Electric

Powered by water pressure alone — zero electricity costs

10 Year Parts Warranty

Comprehensive manufacturer warranty with 2 years labour

Compact Design

Just 205mm wide — fits under a standard kitchen sink

The TwinTec S4 is a compact, non-electric twin-cylinder water softener designed and manufactured in England for homes with up to 3 bathrooms. Its twin parallel cylinder design ensures a continuous supply of softened water 24/7 — with no downtime during regeneration.

Technical Specifications

Dimensions (H x W x D)490 x 205 x 440mm
Salt TypeBlock Salt (2 x 4kg)
Suitable For1-3 bathrooms
Peak Flow Rate56 litres per minute
Water Pressure Range1-10 bar (PRV recommended above 6 bar)
Regeneration Time11 minutes
Water Per Regeneration17 litres
Salt Per Regeneration300g
Power SupplyNon-electric (water pressure powered)
Warranty (Parts)10 years
Warranty (Labour)2 years (manufacturer service team)
CertificationsWRAS Approved, BS14743 Compliant

Product Description

Pioneering Twin-Cylinder Technology

The TwinTec S4 features a unique twin parallel cylinder design that sets it apart from single-cylinder softeners. While one cylinder regenerates, the other continues to supply soft water to your home — ensuring you never experience a break in supply. The entire process is powered by your incoming water pressure, with no timers, motors or electrical components to fail.

Smart Shuttle Metering

Using breakthrough smart shuttle metering technology, the S4 is designed and manufactured to cater for the intricacies of all British plumbing systems. From tanks in the loft to combination boilers and high-flow unvented hot water cylinders, the metering system measures your water usage precisely, only triggering regeneration when necessary. This demand-based approach saves both salt and water compared to timer-based systems.

TwinTec S4 Water Softener installed under a kitchen sink

Compact Design, Great Performance

At just 205mm wide, the TwinTec S4 is designed to fit neatly under your kitchen sink without compromising space. Despite its compact footprint, it delivers a maximum peak flow rate of 56 litres per minute — more than enough for power showers and megaflow systems. The unit takes standard 2 x 4kg block salt, which is easy to handle, widely available and keeps running costs low.

Low Running Costs

The S4 is non-electric, saving energy with zero electricity costs. It only regenerates when needed, using just 300g of salt and 17 litres of water per regeneration cycle. The 11-minute regeneration process is one of the fastest on the market, and because the second cylinder continues working throughout, your household supply is never interrupted.

Designed and Manufactured in England

The TwinTec S4 is designed and manufactured in England to work with all British plumbing systems. It is WRAS approved and conforms to British Standard BS14743, giving you confidence in its quality, safety and performance. Backed by a 10-year parts warranty and 2-year labour warranty from the manufacturer, and durability tested to exceed UK standards.

Ben from Southern Softflow

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What To Expect

1

Speak To Us & Survey

Give us a call or complete our simple 60 second form. We will arrange a free home survey at your convenience.

2

Tailored Solution & Quote

We will visit your home, assess your needs and provide a no-obligation quote for the best solution.

3

Installation

Our experienced engineers will install your new water softener or drinking water system at a time that suits you.

4

Ongoing Support & Salt

We offer ongoing support, servicing and salt delivery to keep your system running smoothly.

Ben Southern working at his desk at the Southern Softflow office
Infinity water softener installed under a kitchen sink with filtration system and copper pipework
Infinity water softener and water filter system installed neatly inside a kitchen cupboard
Southern Softflow engineer delivering Harvey block salt to a customer doorstep

Our Services

We offer a full range of services from sales & installation of water softeners to ongoing maintenance and supplies

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What Our Customers Say

“Southern Softflow’s response to my call for help was amazing, from Edith in the office, Keith the boss man to Will the plumber who worked so hard and did a first class job. A truly great personal service not found easily these days. My heartfelt thanks to them all !”

“We recently had Southern Softwater visit our home to walk us through the available options, and the experience from start to finish was excellent.The initial consultation was clear, informative, and pressure-free. They took the time to understand our needs, explained the different systems in a straightforward way, and answered all of our questions patiently. It felt like they genuinely wanted to help us make the right decision rather than just make a sale.The installation process was just as impressive. The installer arrived on time, was extremely professional, and worked efficiently while keeping everything tidy. He explained how the system works, made sure everything was set up perfectly, and left the area clean once the job was complete.Overall, we’re delighted with both the service and the product. It’s rare to find a company that delivers such a smooth and professional experience from consultation through to installation. Highly recommended.”

“I have dealt with Southern Softflow for 22 years. Recently after 22 years a fault developed on the machine. The machine was taken away and repaired at a very reasonable cost. As I had moved house I had the machine installed by the kitchen company installing the kitchen and they made a poor job of the pipework needed. When Will from Southern Softflow brought the repaired machine back he rerouted the pipework and put new valves in and did a very neat and professional job. I am delighted. A very genuine and professional company ,a delight to deal with.”

“Moving home to an area with very hard water, I decided it was time to install a water softener. After research, I chose Southern Softflow, who offered exactly the reassurance and expertise I was seeking. Decision to installation took two days. Installation itself took a little over two hours, was carried out neatly, efficiently, and professionally. The new tri-flow drinking tap looks great in the kitchen, and even though I’ve used Brita filters for years, tea already tastes noticeably better after only 12 hours. Many thanks to Ben, Will, and the team, greatly appreciated. A full 10 out of 10.”

“Fantastic service from the Southern Softflow Team! My enquiry was dealt with promptly and expertly. We were first told by the guy from another local company who installed our water softener (before we owned the property) that the softener couldn’t be serviced reliably as it hadn’t been used for a while and was in any case 10 years old so in need of replacing. We were also told it would be unsafe to use and were quoted a heavy price by him to replace it. Keith from Southern Softflow came to have a look, He was knowledgeable, friendly and very understanding. He spent time analysing the water to make sure it was safe to use. He flushed the system through thoroughly and assured us the softener is in good working order so we wouldn’t need to replace it which was a great relief. Several weeks after Keith’s visit we are using our softener with no issues and are very relieved Southern Softflow operate in our area!”

“We've had fantastic service from Southern Softflow from initial enquiry through to installation and beyond. This is our first water softener (TwinTec S5) and we can't fault it (we wish we'd installed one years ago). Southern Softflow's friendly and accommodating service is what set them apart from other companies that quoted. There was no pressure to place an order, and they were very accommodating, as this softener was purchased during a renovation of the whole downstairs, including new kitchen, bathroom & plumbing throughout, so they had to coordinate with our plumber and fit in around other trades. Competitively priced. Fantastic product. Excellent service. I highly recommend Southern Softflow.”

Emily, a Southern Softflow customer, sharing her testimonial in her kitchen

Are You Fed Up With The Impacts Of Hard Water?

Emily was looking to protect her new build home in Shaftesbury, Dorset from the impacts of limescale. After living in her new house for two years ago and consequently became frustrated with the impacts of limescale.

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