A reverse osmosis system pushes water through a very fine membrane to reduce dissolved salts, many metals and other impurities that ordinary filters cannot catch. Households use it for drinking water under the sink, and businesses use larger units for coffee, ice or cleaning. It suits areas with brackish borehole water or very hard tap water. Describe your water and your needs, and independent installers in your area send quotes for the system, the fitting and the servicing. It is free and carries no obligation.
How a home RO unit works
Most home systems run in stages inside one compact set:
- Sediment filter: catches sand, rust and silt so they do not block the membrane.
- Carbon filter: reduces chlorine and taste, and protects the membrane.
- RO membrane: separates most dissolved salts and many metals from the water.
- Storage tank and tap: the unit makes water slowly, so it fills a small tank and you draw from a separate tap.
Some units add a final polishing filter or a UV stage. See UV water purification.
Who needs reverse osmosis, and who does not
RO is a good fit when water has a high dissolved salt content, which shows up as salty or bitter taste, scale on kettles and taps, or white deposits. This is common on boreholes in dry parts of the country. It is not always needed on soft, treated municipal water, where a simpler under-counter filter may do. A laboratory test tells you what is in the water, so ask the installer to recommend a unit from your result and be wary of anyone who promises results before seeing it.
What to know before you buy
RO makes waste water. The membrane sends a share of the incoming water to the drain as a concentrate, so ask how much and where it goes. You also need adequate water pressure, often with a small booster pump if your pressure is low, and a nearby drain and plug point for the pump. Membranes last longer on clean feed water, so a good pre-filter matters. Ask how often the cartridges and membrane are changed and what that costs.
Pricing guide: about R1,500 to R4,000 for a home unit, plus R1,200 to R2,500 to install. Larger and business systems are quoted per site.
Comparing RO quotes
Ask each installer for the same details: the number of stages, how much treated water the unit makes in a day, the size of the storage tank, the warranty and whether installation, a booster pump and the first filters are included. Check that a service plan exists, since an unserviced RO unit loses its benefit. For a whole building, compare with filtration and purifier options, and for sites with large demand, look at commercial water purification.
What to include in your request
- Your water source and any lab test result
- Whether the water is salty, hard or has a taste
- How many people and how much drinking water
- Water pressure and where the drain is
- Home or business, and your suburb or town
Reverse Osmosis Systems for different sites
- Households: an under-sink RO unit with its own tap for drinking, cooking and the kettle
- Offices and business parks: an RO unit on the kitchenette supply feeding the coffee machine and a dispenser
- Schools, crèches and colleges: an RO unit for staff and tuck shop use where tap water is hard
- Clinics, practices and care homes: an RO unit for drinking water and equipment rooms, serviced on a written schedule
- Lodges, hotels, restaurants and events: an RO unit for ice, coffee and drinking water in a restaurant, guesthouse or lodge
- Factories, mines and building sites: larger RO sets for canteens, laundry, cleaning and process water on the factory floor
- Shops, gyms and refill stations: an RO unit behind a coffee shop, salon or car wash where scale spoils equipment
- Farms, smallholdings and villages: an RO unit on brackish borehole water at a farmhouse, lodge or school, after a lab test
Frequently asked questions
How much does a reverse osmosis system cost?
Does reverse osmosis remove everything from water?
Does an RO system use a lot of water and power?
Can you fit a reverse osmosis system for me?
Reverse Osmosis Systems by province and city
- Johannesburg
- Pretoria
- Centurion
- Midrand
- Sandton
- Randburg
- Roodepoort
- Krugersdorp
- Randfontein
- Germiston
- Boksburg
- Benoni
- Kempton Park
- Alberton
- Vanderbijlpark
- Vereeniging
- Durban
- Pinetown
- Pietermaritzburg
- Richards Bay
- Newcastle
- Ladysmith
- Gqeberha (Port Elizabeth)
- East London
- Kariega (Uitenhage)
- Mthatha
- Cape Town
- Bellville
- Paarl
- Stellenbosch
- George
- Worcester
- eMalahleni (Witbank)
- Middelburg
- Secunda
- Mbombela (Nelspruit)
- Rustenburg
- Brits
- Klerksdorp
- Potchefstroom
- Mahikeng
- Polokwane
- Tzaneen
- Kimberley
- Upington
- Bloemfontein
- Welkom
- Sasolburg