About Us Contact Us Easy Returns Privacy Shipping Terms of Service
Skip to content
Under sink reverse osmosis system for sale

Undersink Reverse Osmosis Systems

Purified Drinking Water, Direct from Your Tap

Find the Right Under-Sink Reverse Osmosis System

Compare compact, tankless, high-flow and remineralising RO systems for UK kitchens. Every model sits discreetly below the sink and supplies purified water through a dedicated drinking-water tap or compatible 3-way tap.

Fast Free DeliveryUK-wide delivery with no hidden fee
Expert Product SupportClear advice before you choose
Hassle-Free ReturnsSupport if your plans change
Ongoing CareHelp with filters and maintenance

Start with What Matters in Your Kitchen

Do not choose on filtration-stage count alone. Cupboard space, dispensing speed, water efficiency and replacement-filter cost will make a bigger day-to-day difference.

01

Compact Kitchens

Prioritise a slim tankless unit or an integrated tank system when cupboard space is limited.

G3P600CROSS SoloRO-101S
View suitable systems →02

Busy Family Kitchens

Choose a higher-output direct-flow system for faster filling and frequent drinking or cooking use.

Hommix 800X12X16
Compare higher outputs →03

Remineralised Water

Look for a dedicated post-filter that adds selected minerals after the RO membrane.

PD600-TAM3PX500CROSS Balance
View remineralising models →04

Simple Non-Electric RO

Traditional tank systems can operate without electricity and provide stored purified water on demand.

RO-101SERO385
View storage-tank systems →
Use the collection filters to narrow the range

Filter by system design, daily output, power requirement, manufacturer and water enhancement.

Browse All RO Systems

Tankless or Storage-Tank RO?

Tankless RO Systems

Produce purified water on demand and usually use a slimmer cabinet footprint. Most require a nearby electrical socket for the pump and monitoring functions.

Read the tankless RO guide →

Storage-Tank RO Systems

Store purified water in a pressurised tank ready for dispensing. They can be a strong fit where electricity is unavailable, but require room for the tank.

Read the storage-tank RO guide →

Shop Under-Sink Reverse Osmosis Systems

Compare the full collection below. Product pages include specifications, filter schedules and compatibility information.

  • Ecosoft reverse osmosis system with tap and glass water
    Ecosoft water filter
    Ecosoft Ecosoft CROSS Solo RO System
    £279.99

    Compact Tankless Reverse Osmosis System Tankless Under-Sink Reverse Osmosis System for Compact Kitchens The Ecosoft CROSS Solo is a compact, ...

    View full details
    £279.99

What to Check Before Buying an Under-Sink RO System

Cupboard dimensions

Measure the usable height, width and depth around pipework, waste fittings and stored items—not just the empty cabinet.

Water pressure and power

Confirm the manufacturer’s inlet-pressure range. Pumped tankless systems also need a suitable socket beneath or near the sink.

Flow and efficiency

GPD indicates production capacity, but dispensing rate and pure-to-drain ratio are more useful for everyday comparison.

Ongoing filter costs

Check how many cartridges the system uses, their expected change intervals and whether replacements are readily available.

Complete Reverse Osmosis Guide

Understand how RO works, what affects performance and how it compares with other forms of water treatment.

Continue Reading →

RO Systems and Waste Water

Learn why concentrate water goes to the drain and which specification helps compare system efficiency.

Continue Reading →

RO Water vs Bottled Water

Compare convenience, storage, plastic waste and longer-term ownership considerations for UK households.

Continue Reading →

Under-Sink Reverse Osmosis FAQs

What does an under-sink reverse osmosis system reduce?

An RO membrane is designed to reduce a broad range of dissolved substances. Exact reduction performance varies by model, membrane, water conditions and certification, so check the individual product specification for the contaminants most important to you.

Does reverse osmosis remove limescale?

RO substantially reduces the dissolved minerals that cause scale in the purified drinking-water line. It does not soften the rest of the home because an under-sink system treats only the water supplied through its dedicated outlet.

Is a tankless RO system better than a storage-tank system?

Not automatically. Tankless units are usually neater and provide direct flow, while traditional tank systems can operate without electricity and store water ready for use. The better option depends on space, pressure, power and demand.

How often do RO filters need replacing?

Replacement intervals vary by system, water quality and usage. Pre- and post-filters commonly need changing more often than the RO membrane. Follow the schedule shown on the individual product page or in the manufacturer’s manual.

Can an RO system connect to a 3-way kitchen tap?

Many can, provided the tap has a separate filtered-water pathway and the connections are compatible. Check both products before ordering or ask us to confirm the combination.

Do under-sink RO systems require electricity?

Most direct-flow tankless systems use an electric pump. Several traditional storage-tank systems work from mains water pressure without electricity. Check the power requirement shown for each model.

Does Regal Flow provide installation?

Regal Flow does not employ an in-house installation team. We can offer product guidance and may be able to introduce an independent installer depending on your location.

Friendly Expert Support

Need Help Choosing the Right RO System?

Tell us your cupboard dimensions, household size, incoming water pressure and whether you prefer a tankless, non-electric or remineralising system. We will help you narrow down the right options.

Contact Our Support Team
Telephone 0121 630 1130 Email info@regalflow.co.uk WhatsApp Message our support team