Reverse Osmosis Systems

A reverse osmosis water filter will remove fluoride, chlorine, chloramine, detergents, lead, pesticides, nitrates, sulphates and much more.

If you want to treat hard water with a reverse osmosis system we recommend installing a Pearl OneFlow before the reverse osmosis water filter because while reverse osmosis treats hard water they can also be damaged by hard water.

If you have any questions about reverse osmosis systems such as deciding whether you need a tank RO system or tankless RO system, call us on 01352 838 281 or send us a message and we'll reply via our help desk.

What is Reverse Osmosis?

Your household water pressure pushes tap water through a semi-permeable membrane and dissolved inorganic solids (such as salts) are removed from your water.

You can remove several impurities using a reverse osmosis system, such as fluoride, chlorine and chloramine, detergents, lead, pesticides, nitrates and sulphates.

After all those impurities have been removed via the membrane and any additional filters, such as a sediment or carbon filter; you're left with clean-tasting drinking water.

What is the difference between Reverse Osmosis and Filtration?

To water treatment professionals the differences between a reverse osmosis water filter and any other water filter system is huge.

Very briefly, RO membranes let through water molecules to give 'purified water' and the waste water with the contaminants goes down your drain. The resulting 'purified' water has up to 99% of everything taken out - including all the good elements.

Water filters on the other hand tend to use ativated carbon block cartridges targeted at a range of impurities typically found in public water supplies. Particulates are removed mechanically and chemicals are adsorbed by the media electrokinetically. These filters waste no water and leave the good elements in your water.

What does a typical Reverse Osmosis system look like?

Reverse osmosis is an incredibly inefficient water filtration process. The flow rate of pushing water through an RO system is much slower than if you were to plumb a water filter directly into your mains cold water pipe.

Look at our table below for a detailed list of the pros and cons of a tank RO system and tankless RO system. Your final choice will come down to factors such as how much water you're likely to be consuming, how much space you have under your kitchen sink, how much you want to pay for an RO system and what features and benefits you might like an RO system to have.

What is a Tank RO system?

Once water has passed through the reverse osmosis membrane it's held in a pressurised drinking water storage tank. This tank gives you a continuous supply of purified water. The larger the tank the more water it holds.

To avoid possible contamination of the RO storage tank it's recommended to completely drain it every couple of weeks.

What is a Tankless RO system?

A tankless RO system provides purified water on demand as it has no storage tank. This type of RO system is generally smaller than a tank RO system, which is an important consideration if you're a bit short of space under your kitchen sink.

A tankless RO system incorporates a powered pump which helps to create the necessary pressure for both the RO process and the delivery of purified water.

Tank vs Tankless: Pros and Cons

Here are the pros and cons of a tank RO system and tankless RO system.

Which RO system is Right for You?

The main difference between a tank RO system and a tankless RO system is how they store and deliver purified water.

We suggest that you opt for a tank RO system if:

• You are on a tight budget and don't want a high initial outlay.
• You want some flexiblity over the type, size of storage tank, and number of reverse osmosis filtration stages.
• You want to connect a coffee machine or fridge ice maker to the RO system.

Or, opt for a tankless RO system if:

• Your expected daily purified water usage is going to be high, and you don't want to run out of water.
• You have low water pressure.
• You want an RO system that is easy to maintain.
• There is limited space under your kitchen sink.

What does a typical Reverse Osmosis system look like?

A typical four stage reverse osmosis system has the following process:

1: Cold water Line Valve: The water source for the reverse osmosis system. It's a valve that fits onto the cold water supply and there's a tube coming out of it that attaches to the pre-filter.

2. Pre-filter(s): Cold water enters the pre-filter, which is normally either a sediment or carbon block. The sediment pre-filter will remove sand, silt, dirt and other sediment that could clog the system and affect the RO membrane. If a carbon filter is used, this will remove chlorine and other chemicals and also improve the taste and smell of your water.

3. Reverse Osmosis Membrane: This is the heart of the reverse osmosis system and where the magic happens. Your water passes through a semi-permeable RO membrane and a variety of aesthetic and health related contaminants are removed. The treated water is then stored in a pressurised storage tank. 

4. Storage Tank: A standard tank will hold between 2-4 gallons of water and is roughly 12" diameter and 15" tall, so it will fit nicely in the cupboard under your sink. A bladder inside the tank keeps your water pressurised until its ready to be pushed out into the post-filter.

5. Post filter(s): Before your water gets to the RO tap, it flows through a final 'post filter'. This is usually a carbon block and it's where the taste and odour of your water are further improved, giving you pure, safe and beneficial drinking water. 

6. Automatic shut off valve (SQV): When the storage tank is full, the SQV closes to stop anymore water from entering the RO membrane. It saves your water and stops it unnecessarily flowing down the drain. As soon as water is drawn from the RO tap, the pressure in the tank drops and the SQV re-opens to let some more water in so that it can pass through the membrane and continue on its journey. 

7. Check valve: this is located in the outlet end of the RO membrane and its purpose is to stop the backward flow of treated water from the storage tank.

8. Flow restricter: This maintains the flow rate to give you the highest quality drinking water on tap. It also helps maintain pressure on the inlet side of the membrane. Without the additional pressure from the flow control, most of your water would simply flow down the drain and be wasted.

9. Tap: Where your pure, safe drinking water comes from. You would normally install this on your kitchen sink and enjoy the benefits of fresh tasting drinking water that's free of any contaminants.

10. Drain line: This runs from the outlet of the ro membrane to the drain and it's used to get rid of your contaminated water that's been through the reverse osmosis system.

Is Reverse Osmosis water good for you?

It's true that reverse osmosis removes some unhealthy contaminants such as arsenic, nitrates, copper, lead, sodium and fluoride from your water, but is it healthy? Here's a few things to think about when you're considering buying a reverse osmosis system.

• Your water becomes demineralised: Most mineral particles such as calcium, magnesium, iron and sodium are larger than water molecules and are therefore removed by the semi-permeable membrane in the reverse osmosis system. Some of the health risks that come with drinking demineralised water include gastrointestinal problems, bone density issues, joint conditions and cardiovascular disease.
• Water will be tasteless: when you remove all of the minerals from your water using a reverse osmosis system, your water is tasteless.
• Water becomes acidic: when the minerals are removed from your water, it makes your water more acidic which goes against what your body needs. The pH balance in your blood should be slightly alkaline, which is why its always recommended that you have an alkaline rich diet.
• Some contaminants are not removed by reverse osmosis: Although our systems have a carbon block filter which removes chlorine and other harmful contaminants, some reverse osmosis systems don't. If you are looking to buy an ro system then we recommend your get a multi-stage one, with a carbon block post-filter.

Does a Reverse Osmosis system waste water?

Yes, RO systems can waste around 3 parts to 1 part purified at best. If you were to use 10 litres of purified water, at least 30 litres will go down the drain. There may also be a need for a pre-filtration stage.

If you are concerned about the water loss then perhaps you should consider one of our drinking water filters and mains water filters. They waste no water at all. 

FAQs

What are the benefits of using a reverse osmosis system?

A reverse osmosis system will remove all contaminants from your water giving you clean, safe, high quality water.

How often should I replace the filters in my reverse osmosis system?

To ensure your reverse osmosis system operates effectively you need to replace all cartridges except the reverse osmosis membrane every 12 months. The membrane only needs to be replaced every 2 to 3 years.

Is the installation of a reverse osmosis system complicated?

Installation of a reverse osmosis system is not difficult. Any competent plumber or handyperson would be able to install it. Everything you need for installation should be included in the reverse osmosis system kit, except for the electric drill.