Can you collect rainwater for drinking? What you need to know

Water is life. Yet, our water sources are becoming threatened in many places across the globe.  Rainwater harvesting is a solution for many of us and in fact the only option for some! I personally grew up drinking rainwater collected off the roof, and continue to use rainwater harvesting now (with some treatment). I find it to be beautifully clean and tasty water and rarely have any issues. Living in an urban or more polluted environment, however, this may not be a safe option and you need to understand the risks. So what are the risks and should you drink your harvested rainwater? Let’s dive in and unravel it all.

Can you collect rainwater for drinking? If you live in a clean environment, where there is very little air pollution, and where you have a roofing material that will not contaminate the water, this may be an option. For safety, it is advisable to treat the water before you drink it. However, there are risks and if you are unsure, you should not consume it. Furthermore, you will likely have local regulations to adhere to and you should always seek to understand the rules. They are there to protect you.

Table of Contents

What is rainwater harvesting and how to collect it?

Rainwater harvesting can be quite simple to set up and can provide a reliable supply of water for a variety of uses. Essentially, it involves capturing, diverting, and storing the water from rooftops or other suitable collection surfaces. The harvested water is stored in a water storage tank, which will be sized to ensure the water is available when you need it. We have a great article that shows you how to calculate the required water storage tank size: What Size Rainwater Tank Do I Need?

Understanding rainwater harvesting: Be the master of your own water supply

As populations grow, catchments become polluted, and climate stressors change rainfall patterns, the future of our water resources in many parts of the world is becoming increasingly uncertain.  Rainwater harvesting allows you to be in control of your own water supply, potentially even providing clean water during periods of water scarcity. If designed correctly, it can help you to become more self-sufficient and less dependent on the public utility water supply. It may even provide a safe source of drinking water if the risks are carefully considered and managed. 

How to set up a rainwater collection system at home?

A rainwater collection system at home generally consists of a catchment (often a roof), a conveyance system (gutters, pipes), water storage (a tank or perhaps a dam), and depending on the quality of your collected rainwater, a treatment method (filtration and/or disinfection). Harvesting rainwater should involve careful planning and design to ensure it works as you intend. Our article, How to Design a Rainwater Harvesting System provides everything you need to know. Also, check out our Rooftop Rainwater Harvesting Calculator to figure out how much water you can generate and if this will be adequate to meet your needs.

Conserve water and save money: The financial, environmental, and self-sufficiency benefits of rainwater harvesting

Harvesting rainwater offers numerous great benefits – it reduces your dependence on the utility water supply either partially, or completely, and therefore saves money on your water bills; it is an important part of preparing for future water scarcity; and it may reduce your environmental impact, depending on the local situation. Think of it as a great way to become more sustainable and self-reliant. 

Rainwater vs tap water: Is rainwater safe to drink?

Rainwater is considered safe to drink in many parts of the world, yet it might not meet the water quality standards without treatment. Let’s investigate this a little further.

What is in your rainwater? Understanding water quality and potential contaminants

Hopefully, nothing is in your rainwater and it is safe to drink! This is certainly the case for many environments and rainwater harvesting systems, however, there are risks that you should be aware of when considering your situation and the use of your collected rainwater.

While rainwater in itself is usually a pure form of water, it can become contaminated. The quality of rainwater varies and is dependent on the following factors.

• Atmospheric air pollution: If there is air pollution in your area, this can contaminate the rain. Various chemical contaminants caused by industry and other sources can dissolve into the water during precipitation. Follow government advice on the quality of air and the risk that it poses to rainwater quality. 
• Catchment: Dust, bird or other animal droppings, and insect waste are among the potential sources of contamination in the catchment (for example your roof). This can introduce harmful bacteria or viruses into the collected water.
• Materials and method of harvesting: The material of your roof, and any paint or other coatings, can introduce unsafe chemicals into your harvested rainwater. Even sealants and glues used in roof plumbing can be a risk. Check the manufacturer’s specifications and safety standards.
• Storage: Your water may be stored for a considerable time between rain events and before it is used. This can allow unsafe bacteria and viruses to propagate. Ensure you are using fit-for-purpose storage tanks and that contamination risk is avoided, for example by screening the inlet. 

Treating rainwater: Removing harmful bacteria, viruses and contaminants

To ensure the collected rainwater is safe to drink, it may need to be treated. Treating rainwater typically involves filtration and disinfection. Filtration removes solid particles, while disinfection kills any remaining bacteria or viruses. I have provided more discussion on the options for you below.

Comparing rainwater to our public water systems

While public water utilities are usually able to ensure a continuous supply of treated and safe water, they can be susceptible to breaks and contamination. The safety of your utility water depends on the local regulations and safety standards. Many developing countries for example do not provide reliable water quality or quantity to their populations.

Public water systems typically add chlorine to the water supply to disinfect. They may add this at the treatment plant and then top up the dose as the chlorine is consumed throughout the network. This keeps it safe for the customer connection. Of course, there is always the risk of contamination within the property which the local utility has no control over. This is your risk to manage and most people are required to use qualified plumbers for any internal works for this reason.

The addition of chlorine can add a taste to the water. You may be familiar with that taste and be surprised if you taste collected rainwater at just how pleasant it can be without chlorine. 

Filtration systems and treating rainwater for drinking

When it comes to making rainwater safe to drink, filtration systems can offer a reliable solution in many situations. Let’s explore some common methods.

Making rainwater safe to drink: Choosing the right water treatment system for home

Choosing the right water treatment system for your home relies mainly on the quality of collected rainwater. Common methods include activated carbon filters, ceramic filters, ultraviolet disinfection, chlorination, and reverse osmosis systems.

Using carbon filters to purify rainwater

Activated carbon filters are a popular choice for treating harvested rainwater. They remove organic compounds, improve the taste, and remove any odor from the water. However, they may not remove all viruses or bacteria.

Some great options on the market are either ‘benchtop’ or ‘under sink’. 

With bench-top or jug-style carbon filters, you’ll fill from the tap and let it slowly filter the water. The image is the one at my house. We think it’s actually quite attractive! For us, this is an adequate level of treatment since we live in a clean environment and simply need to remove any rooftop catchment contamination risk.

With under-sink models, you’ll plumb them directly into the cold water supply. This can save space on your bench and can be more convenient. 

There is a need to sway the carbon filters out periodically, depending on the quality of your rainwater. Follow the manufacturer’s instructions. 

The role of disinfecting rainwater in providing safe drinking water

You can disinfect rainwater to kill viruses and bacteria if this is a risk for you. It can be done in a number of ways, including boiling, chemical disinfection, ultraviolet light, and ozone treatment. There are various systems available on the market with varying performance and maintenance requirements. Some systems require considerable power to operate, or chemical additions which will come at a cost and you’ll need to understand the system and its operation. 

Risks and challenges of using rainwater for drinking

While harvesting rainwater offers numerous benefits, it isn’t without its challenges and potential risks.

Understanding the potential risks of drinking rainwater

The biggest potential risk of drinking rainwater is to your health and comes from contamination. As we’ve discussed, this depends on your local environment, the level of atmospheric air pollution, your roof catchment and collection method, and how you store the water. Harvested rainwater can carry dirt, harmful bacteria, and viruses, and can even be acidic if exposed to certain air pollution and roofing materials, etc.

Is it legal, and what governmental regulations exist on harvesting and drinking rainwater?

In most places, it is legal to collect rainwater for drinking, but this can vary from one region to another depending on local restrictions or regulations. It is always advisable to check the local regulations before setting up a rainwater harvesting system. And of course, not only are you obliged to follow the local regulations, but you should for your health. They are there to keep you safe.

A Final Thought

So, can you collect rainwater for drinking? As we’ve discussed the answer depends on your situation. If you live in a clean environment with very little air pollution, and if your roof catchment is appropriate, this may be an option. For safety, it is advisable to treat the water before you drink it. 

There are risks that you should seek to understand, and if you are unsure, don’t consume it. 

There may well be local regulations that you must adhere to and you should always follow the rules.

However, with the right set-up, harvesting and drinking rainwater could be a good, safe option that yields cost savings and self-sufficiency. If you can do it safely, go ahead and enjoy the great taste of your home-harvested rainwater!

FAQs

Q: What do I need to start collecting rainwater for drinking?

A: To begin, you’ll need a set-up to collect and store rainwater. This might include rainwater barrels, buckets, or a more sophisticated rainwater collection system. Additionally, as rainwater may contain impurities, you need a reliable water filtration system to ensure the harvested rainwater is safe to drink.

Q: Is it really beneficial to drink collected rainwater?

A: Rainwater in itself is a very pure form of water and can be a safe and beneficial source of drinking water. However, it can become contaminated and must be properly collected, stored, and treated to ensure it is safe to drink.

Q: How does one ensure that the collected rainwater is safe to drink?

A: You’ll first need to ensure that there is no risk of contamination from atmospheric air pollution. Check with your government regulations and guidelines on this. Once set up, it’s important to regularly clean your rainwater collection system and use a water filtration or other treatment system. Testing the water frequently for contaminants and treating water with chlorine or other disinfectants is also advisable to make sure the rainwater is safe for drinking.

Q: Can I use harvested rainwater for other purposes?

A: Absolutely! Apart from potentially being a source of clean drinking water, collected rainwater can also be used for watering plants, washing clothes, flushing toilets, and bathing. This can help to lower your water bill and conserve water.

Q: What can contaminate rainwater and how do I prevent it?

A: Airborne pollutants, bird droppings, insects, and roof or plumbing materials can contaminate rainwater. To prevent this, check manufacturers’ specifications to ensure materials are fit for purpose, maintain clean gutters, use a rainwater screen at collection points, and treat the collected water properly before using it.

Q: Can drinking rainwater make you sick?

A: If not treated properly, drinking rainwater can make you sick as it may contain bacteria, viruses, and harmful chemicals.

Q: How should collected rainwater be stored?

A: Rainwater should be stored in a tank made from appropriate materials that are safe for drinking water, and it should be maintained correctly. This may mean periodic flushing of the system to remove sediment and other contaminants.

Q: How can rainwater collection help me lead a more sustainable lifestyle?

A: Harvesting rainwater can help reduce your dependence on municipal water supply and lower water bills. It is a renewable, environmentally friendly means of obtaining water that can be used for many purposes around the home and garden.

Q: Can collected rainwater be my primary source of drinking water?

A: It can, if your area receives adequate clean rain, and the system is designed correctly.