Whole House Reverse Osmosis on Private / Raw Water Supply

The default whole of property Reverse Osmosis  is designed for use with mains (municipal) water. If you intend to use it to filter a private supply (boreholes, srings, wells, rivers etc), have the water fully tested first and install any extra treatment needed - we can help you with this.

You face the following possible issues - in order of likelihood:

Bacteria / Viruses / Micro-organisms

• The risk: Bacteria in the incoming water can build up in the Main RO Unit's pre-filters, membranes and storage tank.

• The Solution:  fit a second Ultra Violet (UV) unit before the Main Reverse Osmosis Unit, so the water is disinfected before it enters the system. Basically you simply need the right size UV depending on your incoming flow rate. (This is part of the non-mains pack we offer).

Note: One UV unit already included with the system is designed to make sure there are no bacteria in the water after it has been sitting in the storage tank. Do not be tempted to remove this! You will need both UV units: one to protect the system, and one to protect the water you drink.

High Iron, Manganese, and Calcium

• The Risk: Raw well water often carries heavy dissolved minerals. An RO membrane will trap them, but they rapidly crystallise on the surface (membrane fouling), permanently clogging and ruining the filter within months.

• The Solution: Simply be prepared to change the membranes more often (takes a few minutes/DIY). Or install a salt water softener and/or an iron/manganese removal filter upstream of your RO system to pull out these minerals before they reach the membrane. These are expensive. We can supply the iron/manganese filter. Salt softeners are widely available.

Agricultural Pesticides and Herbicides

• The Risk: Stream runoff from nearby farmland can carry heavy seasonal spikes of crop chemicals. Certain low-molecular-weight pesticides can bypass or degrade a bare RO membrane over time.

• The Solution: Extra Carbon filters can lock away complex agricultural chemicals. The carbon pre filter in your Main RO unit will definitely help. But it’s wise to get an additional Carbon pre-filter. Select one depending on your incoming flow rate.  (This is part of the non-mains pack we offer).

Sediment, Silt, and Organics

• The Risk: Stream water carries dirt, clay, and decaying plant matter. This debris will obstruct the  crucial RO membrane and block your UV light from properly sterilising the water.

• The Solution: Deploy a high-capacity 5-micron sediment pre-filter at the very beginning of your water supply line to keep the water crystal clear. (This is part of the non-mains pack we offer).

Dissolved Radon and Methane Gases

• The Risk: Deep wells can trap toxic radon or flammable methane gas. Because dissolved gases are uncharged and incredibly small, they slip right through an RO membrane into your drinking water.

• The Solution: Use an aeration system at your home’s water entry point to vent these gases safely outside into the atmosphere.

You might have other issues which is why you should always get a full lab water test (including microbiological) before installation.

You then install the unit and take tests on the product water after installation.

Note: seasonal variation

Because the variables affecting feed-water quality are so wide, and can change - for example with the seasonal water supply or for other reasons - we can't tell you in advance exactly what your particular supply will need.

Retrofitting pre filters

You could get the main whole house RO unit unit and retrofit any pre-filtration if it proves necessary.

Sometimes it just won't work

The system should work fine in 99% of cases. But please be aware that if you're essentially drawing from a large stagnant source - such as an old quarry - rather than a reasonable supply such as a rain-fed stream or aquifer, it may not be workable for you eg you will need too many pre-filters changed too often. 

About our advice and responsibility

We're always happy to help and to share what we know, for free and without obligation. But please treat this information as general guidance to help you decide, not as a bespoke assessment of your specific site.

We do not test or survey your individual water supply, so we can't confirm what your particular conditions require.

You know your own supply best, so the final decision on whether the system and any pre-filtration are right for your local conditions rests with you.

If you're unsure, get your supply tested and, where appropriate, take advice from a local qualified water treatment specialist who conducts a site visit - which we don't do. (Please note: nothing here affects your legal rights.)

Back to full information on our whole-of-property Reverse Osmosis filters.