Reverse Osmosis

This water treatment process removes contaminants from water by using pressure to force water molecules through a semipermeable membrane. During this process, the contaminants are filtered out and flushed away, leaving clean, delicious drinking water.


Reverse osmosis (RO) is a water purification process that uses a partially permeable membrane to separate ions, unwanted molecules and larger particles from drinking water.

A reverse osmosis system sends water with rejected contaminants down the drain as wastewater, unlike other filters that trap contaminants. As water flows through the system, it’s divided into two streams. One stream carries the filtered water to a dedicated faucet, and the other stream carries the removed salts, dissolved pollutants, and minerals to the drain.

The brine or “wastewater” carries rejected contaminants from a reverse osmosis system to the drain. 4 gallons of water exits the drain for every gallon of water produced. But the brine water is used for a purpose, so it’s not exactly wasted. The wastewater in an RO system helps clean the water, just like a dishwasher uses water to clean dishes or a washing machine uses water to clean clothes. However, it’s our job in caring for the environment to minimize the amount of water sent to the drain and increase the efficiency of the RO system.


While it’s well known that municipal tap water contains chlorine and that this can impart a chemically or medicinal taste, it’s less well known that various salts and minerals (total dissolved solids or TDS) can also be present in mains tap water.

Though small amounts of certain minerals such as calcium and magnesium can actually aid extraction of flavour, others such as chlorides and sulphates can cause coffee to become sour or bitter – not good news when you’ve forked out for incredibly rare and expensive coffee beans grown by the indigenous tribes of the Chalatenango Mountains in El Salvador.

As well as a deleterious effect on the flavour of your coffee, these dissolved minerals can also damage your equipment. Everyone’s familiar with the scale build-up that occurs inside domestic kettles in hard water areas. Well, the same thing is happening inside the boiler of your espresso machine. Though a descaling regime can remove scale from inside a machine, the highly acidic chemicals required can be difficult to handle safely and tricky to dispose of responsibly. Repeated use of strong descaling solutions can also reduce equipment lifespan.



Frequently asked questions

Reverse Osmosis works by using a high pressure pump to increase the pressure on the salt side of the RO and force the water across the semi-permeable RO membrane, leaving almost all (around 95% to 99%) of dissolved salts behind in the reject stream.

Reverse Osmosis Systems will remove common chemical contaminants (metal ions, aqueous salts), including sodium, chloride, copper, chromium, and lead; may reduce arsenic, fluoride, radium, sulfate, calcium, magnesium, potassium, nitrate, and phosphorous.

The process of reverse osmosis reduces salt, minerals and any other impurities. … RO systems are less efficient than water softeners, so they’re usually installed at a single point-of-use, like a kitchen sink, rather than used for the whole house.

RO removes lead from water and frees people from many diseases such as high blood pressure, nerve damage and low fertility. Drinking reverse osmosis water can also eliminate risks of brain damage and anemic conditions, especially in children.

RO water which doesn’t contain enough minerals, when consumed, leaches minerals from the body. This means that the minerals being consumed in food and vitamins are being urinated away. Less minerals consumed plus more minerals being excreted causes serious negative side effects and big health problems.

Portawater Uk Ltd has been installing softners for both commercial and domestic for more than 35 years.