Can you drink rainwater? Rainwater harvesting in the UK

If you knew for certain that your rainwater was clean and free of any contaminants it would be perfectly safe to drink and we would all be encouraged to collect it, drink it, and enjoy it. The nation would be lapping it up!

But we hate to put a spanner in the works and tell you it’s not quite as straightforward as that because physical, and environmental factors play a part and rainwater isn’t nearly as pure as you might initially think.

Never assume that you can drink rainwater. If you don’t know what’s in your rainwater, it’s probably best to err on the side of caution and avoid drinking it.

If you want to use rainwater but not drink it, feel free to use it in the garden, wash your car with it, and fill your washing machine with it.

In this article we set out to answer some key questions about drinking rainwater including ‘can you drink rainwater’? ‘Is rainwater safe for drinking’? making rainwater safer by looking at rainwater filter options. We’ll also touch on the fundamentals of rainwater harvesting, specifically rainwater harvesting for drinking in the UK.

Can you drink rainwater?

There’s a difference between ‘can you drink rainwater’ and ‘should you drink rainwater’.

If you find yourself in a survival situation and rainwater was the only drinking water source available to quench your thirst, then the ‘should you drink rainwater’ question would be easily answered. That rainwater could be the difference between life and death. However, we’d like to think that most of us are not in a survival situation day in and day out.

Leaving the survival scenario aside, as water filtration experts we wouldn’t recommend drinking rainwater unless you’d had it properly tested and treated if necessary. You must be 100% certain that it’s safe as there could be parasites, bacteria, heavy metals, animal or bird faeces, and viruses lurking in it. Any of these contaminants would pose a significant health hazard to anyone drinking that water.

As rain falls from the sky it collects particles and contaminants. As rain hits your roof it soaks up anything that happens to be up there. And how many of us know what’s on our roof? Lots of lovely bird poo probably! You can be sure that rainwater will absorb anything that it passes through.

It’s all starting to look like that pure, clean, fresh rainwater isn’t quite as refreshing and appetising as we hoped. Cue upset stomach.

Can you tell we’re steering you towards believing that no rainwater is safe to drink.

Is rainwater safe to drink?

The temptation to just say NO and move on is strong, but that’s not going to equip you with the information you need on the subject of ‘is rainwater safe to drink’?

Rainwater not safe to drink should be emblazoned across the sky in huge letters!

We’ve touched on some of the reasons why drinking rainwater may not be the perfect way to stay hydrated. Having an upset stomach would be bad enough, catching a nasty disease even worse, and dying for the sake of a sip not worth it at all. Bacteria, viruses, parasites, and anything else rainwater picks up on its journey from the sky to your mouth means that it’s not the ideal thing to do. Contaminants don’t jump out of the water and say ‘hey, be careful – I could make you very ill’!

If rainwater was safe to drink, surely the UK wouldn’t need to treat it, concentrating instead on treating groundwater sources. They’d just collect rainwater, store it, and pump it directly to your tap. We’d all be super healthy!

Rainwater myths

While writing this article we’ve come across some interesting and potentially misleading information out there on the world wide web. Here’s a couple of things that made our jaws drop.

• Rainwater is more alkaline than tap water – NO. It’s the opposite. Rainwater is generally slightly acidic with a pH of 5.0-5.5. Rainwater becomes even more acidic when it combines with sulphur dioxide or nitrogen oxides that are generally produced from emissions from power plants and cars. The higher the pollution, the higher the acidity of the rainwater. You’ve probably all heard of the term ‘acid rain’. Depending on where your tap water is sourced, it’s generally more neutral or alkaline – pH 6-8.5.
• Rainwater is good for the body – we’ve read that it keeps bones healthy, nourishes the cells in your body, and boosts your immune system. Yes, water does all these things and that’s marvellous, but in everything we’ve read it does stipulate that rainwater should be treated before drinking. Isn’t one of the sources for tap water just rainwater that’s been treated. All those articles that we’ve read just come at the ‘can you drink rainwater’ issue from a different angle. The only difference between rainwater and tap water is that rainwater won’t contain chlorine.

The information out there on rainwater can be misleading, so be careful!

How to filter rainwater to drink

We hope that we’ve made is clear that regardless of how you’ve collected it, no rainwater is safe to drink. Rainwater is only safe to drink AFTER you have treated it.

Our focus here is on how to purify rainwater for drinking at home, so we’ll skip the use of water purification tablets as a rainwater filter method.

Let’s look at some options so that you can choose a rainwater filter system that suits your needs.

Boiling rainwater

Can you boil rainwater and drink it? Yes, it’s a key step in making rainwater safer to drink. Boiling water will significantly improve the quality of the rainwater and will remove certain types of bacteria, viruses, or parasites. You will most likely need an additional rainwater filter to remove chemicals and any other contaminants not removed by boiling.

The boiling point of water is 100°C / 212°F. But did you know that the boiling point of water can be affected by how many impurities are present.

Water to Go bottle

Can you collect and drink rainwater? You most certainly can with a water filter bottle by Water to Go.

It’s an ideal rainwater filter system when you’re on the move. You can basically fill up your bottle with rainwater or any other non-saltwater source.

We get quite excited by the Water to Go filter bottles because it means you’ll never run out of clean fresh water.

Try these water filter bottles yourself. Collect some rainwater in a clean container in your back garden and then pour it straight into your Water to Go bottle. It really is that simple.

Rainwater filter

Can you drink filtered rainwater? Absolutely!

And this is where we can help you filter out a variety of parasites, bacteria, heavy metals, animal or bird faeces, and viruses from your collected rainwater.

If you can get your rainwater tested regularly that would be useful in determining what’s in it that you need to filter out. Remember, that the composition of rainwater doesn’t stay the same. We recommend that your rainwater is stored in a sealed tank after treatment and that this water tank is disinfected regularly with something like bleach or Milton disinfecting fluid.

You need sufficient water pressure in the collection tank to push the water through to the rainwater filter system. This means the collection tank must be situated at least 10 metres above the filtration stage. Or you could use a water booster pump.

So, what type of rainwater filter do you need to make it safe to drink?

You’ll need to remove both large and small particles using either a spin-down filter or a single or twin sediment filter system (or both). You will need to contact us directly for information on spin-down filters.

Chemicals can be removed using a carbon block water filter cartridge. This type of cartridge can be found in many of our drinking water filter systems and mains water filter system for home.

The removal of bacteria, cysts, and microorganisms is best tackled by an Argonide NanoCeram water filter cartridge. These are available in three different sizes for either drinking water only or wholehouse contaminant removal.

An alternative to the NanoCeram water filter cartridge would be to use a UV water treatment system to remove bacteria, cysts, and microorganisms.

A combination of one or all the rainwater filters above will ensure that your rainwater is safe to drink.

Rainwater harvesting to drink

Before we draw this article to a close, it’s important not to forget about rainwater harvesting as a means of collecting, storing, and using water that falls from the sky.

What is rainwater harvesting?

Rainwater harvesting is essentially the collection and storage of rainwater that falls onto the roofs of buildings instead of letting it run-off down the gutters and into the drains. In the long-term rainwater harvesting can be a more sustainable way of running your home and saves you money on your water bills because it cuts down your use of mains water.

People choose to harvest their rainwater to use it for non-drinking purposes such as flushing the lavatory, in washing machines, and watering the garden. A properly set up rainwater harvesting system will filter the rainwater and store it below ground where it’s less likely bacteria will form.

What’s good about rainwater is that it doesn’t create limescale and so if you’re using it to flush the loo or in your washing machine it doesn’t create that horrible scale that hard water tends to.

Can rainwater harvesting be used for drinking water?

If you wanted to use a rainwater harvesting system for drinking water, it would have to go through some sort of rainwater filter to make it potable. If you didn’t do this you would not be able to use it for drinking, washing in, or cooking.

We’ve talked about some of the rainwater filter systems already.

We believe it would only be economically viable to make your rainwater potable if you were living in an area that had no mains water connection. If you are on mains water then it would be more beneficial to use your harvested rainwater for non-drinking purposes and stick to mains water for drinking, washing in and cooking.

We hope that we’ve provided you with sufficient answers to the question of ‘can you drink rainwater’ and provided a small insight into the concept of rainwater harvesting.

In conclusion, if rainwater is properly treated then it would be safe to drink, but only if necessary. If you are on mains water, it would make more sense to limit the use of rainwater to non-drinking purposes.

We do love those water filter bottles though!

We’re easy to contact if you have any questions about rainwater. You can call us on 01352838281 or use our valuable helpdesk to send us a message.