Should you use a Reverse Osmosis system as a Rain Water Filter?
It’s entirely possible to treat your rain water using a Reverse Osmosis system, but we certainly don’t recommend it, mainly because of the water wastage.
When you use Reverse Osmosis, the membrane splits the water in half, sending half down the drain and half into your storage tank for consumption.
This article provides an in-depth look at the reasons why you shouldn’t use a Reverse Osmosis system to treat your rain water.
First, the two main options we are discussing for filtering rain water are:
- Mechanical filtration using filters and;
- Cartridges Reverse Osmosis
Rain Water Filtration
Already, there is not that much wrong with rain water.
Let's face it, it comes from the clouds, lands on the roof of your house, and from there it falls into your water tank before being pumped throughout your home.
If you've got a concrete water tank, lime leeches out of the walls and into the water, which elevates the pH to about 7 - which is ideal for drinking.
Next, all that is required is to remove sediment and any herbicides, pesticides, or heavy metals picked up from the roof or gutters.
If you haven’t got a concrete tank, that water stays at the 6pH mark, which is acidic. Now, consuming acidic water creates all sorts of problems for your health, so we do not recommend drinking water below 7pH for that reason.
Regardless of what your tank is made from, there is still not much that needs to be done to prepare your water for consumption.
Do I Really Need A Reverse Osmosis System
The following are excellent reasons you should use a Reverse Osmosis system:
- If you’re on city treated water
- If you’re on bore water
- If you’ve got a water softener and you need to get some nasties out of your water.
Because most Reverse Osmosis systems have the same filtration steps as a mechanical filter, all that’s required after the first two steps is to raise the pH. Simple.
Stage 1 is your Sediment filter, taking out the lumps, bumps and rainwater sediment from your rooftop and gutters.
Stage 2 is your Carbon filter; it takes care of any herbicides, pesticides or heavy metals that could be in the water.
Stage 3 is usually the membrane, which splits the water, immediately removing all contamination and disposing roughly 50% of your water.
Stage 4 is usually an alkaliser cartridge to raise the pH again and replace some of the mineral lost in the membrane step.
It’s completely unnecessary to use a Reverse Osmosis system to treat your rain water; it’s just wasting water.
How To Filter Rainwater
Filtering Rainwater for Drinking is simple.
These systems can be purchased in single, twin and triple stages.
In a triple Benchtop or Under Sink Water filter, the filtration steps look like the below:
Cartridge 1: Sediment filtration. We're taking all the sediment out here with this first cartridge, then it flows over, and then it's going through the Ultrapure.
Cartridge 2: Ultrapure cartridges. So this system here takes all the bugs, bacteria, herbicides, pesticides, heavy metals out of the water, making the water now safe to drink - if you’ve got a concrete tank.
Cartridge 3: Alkaliser. The alkaliser is similar to the big alkaliser at the top of the RO.
It's just a cartridge full of minerals. As the water goes through, it's like food for the water, and the water eats that mineral up, and it dissolves into the water, elevating the pH.
If you use an alkahydrate cartridge like the one in the video above, it'll elevate your pH straight up to about nine. As the cartridge ages, the water produced will reflect a declining pH before you need to replace your cartridge at about 7pH. This usually happens over the course of a year.
We never want anybody to drink water below seven because of its acidity.
Don’t use RO as a Rainwater Filtration system.
Click here to read more about why you should always consume water with a pH of 7 or above.
Click here to see our full collection of Benchtop and Under Sink Systems to treat your rain water. Alternatively, filtration systems you can install at your rain water tank.