Rain Water Tank Water Filters: Overview and Recommendations

A couple of things can stand in the way of perfect rain water. First up, rain water is naturally acidic. As raindrops fall through the air, they absorb carbon dioxide, which lowers their pH. Over time, this acidic water can damage the copper pipes in your home and even cause health issues to you and your family.

Have you ever spotted those blue-green stains in your toilet, bath, or on your basins? That’s a tell-tale sign of acidic water. It's literally the colour of copper being eaten away from your pipes. If you let it go, you can end up with tiny holes in your pipework, which can lead to bigger headaches like mould and mildew.

The other main issue is bacteria. Any stored water can become a breeding ground for bugs, sediment and other nasties. If your gutters collect leaves and debris, there’s a good chance bacteria is finding its way into your tank. Before that water is used in your home, it needs to be purified. Luckily, a good rain water tank filter paired with a UV light takes care of this quite effectively.

A great starting point is to install a 20” x 4.5” Big Blue Rain Water Tank Filter, which can filter and remove a lot of the sediment, bugs and debris from your water. These systems are designed for high flow, so they’re perfect for any home, no matter how many people are using the water. They work for both gravity-fed systems and homes that use a pump.

But to be certain you’re zapping all the bacteria, you need a UV light as well. This is especially important if your tank tends to get a bit leafy or dirty. If you’re not planning on adding a UV light, then grabbing an Aragon or Disruptor cartridge for your filter is a must for that extra layer of protection.

Once you've stopped the larger debris, the next step is to deal with bacteria. If your gutters or tank are full of dirt and leaves, a UV light installed alongside your main water tank filter is the best way to make sure the water coming into your house is completely sterile.

We also suggest using a product like Hydrosil to give your pipe network a good disinfection after the UV light is installed. It’s a great way to ensure there’s no residual bacteria hanging around inside your pipes. As a backup plan, for times when the power might go out, having a single Aragon or ceramic filter under the sink for your drinking water is a brilliant idea.

Rain water typically has a pH between 5.0 and 6.0, which is quite acidic. To protect your health and your home, you’ll want to get that number back up to a neutral 7.

As we mentioned, those blue-green stains are a sign that acidic water is eating away at your copper pipes. For tank water, the best solution is to install a pH elevation vessel, which is really good at raising the pH of your water and preventing corrosion in your pipes.

Now, if you have a concrete water tank, you can probably skip this step. The lime from the concrete naturally leaches into the water and makes it more alkaline. For any other type of tank, your water is likely to be acidic and will need some attention.

You can definitely target specific taps, like the one in your kitchen. An under sink UV steriliser will do the job just fine. However, they do tend to generate a bit of heat under the sink, which means the water in the line can get quite warm. Another thing to consider is that if the power goes out, you lose your disinfection. We recommend using a quality ceramic or Aragon filter under the sink. That way, your drinking water is always protected right at the point of use.

You can also get smaller pH elevation systems that fit right under the sink to raise the pH of your drinking water. You never want to be drinking acidic rain water; it’s just not good for your body.

After the water is fed through the home, we recommend a point-of-use drinking water system inside, at the kitchen sink. See our benchtop and under sink drinking water filters.

Whatever you need for your water filtration, we’re here to help you get it sorted. If you have any questions, please feel free to contact us.