Can You Drink Rainwater?

As an increasingly popular (but often misunderstood) water source, you might have considered harvesting rainwater for drinking. It is, after all, abundant, convenient and best of all – FREE.

In the UK, rainwater harvesting is becoming an increasingly popular solution for sustainable water use. According to industry estimates, over 1,200 properties in Anglian Water’s supply area alone have rainwater reuse systems installed, and that number is growing. With average UK household water use around 142 litres per person per day, and up to 40% of that used for non-potable purposes like toilet flushing and laundry, rainwater harvesting can be a practical way to reduce reliance on mains water.

Can You Drink Rainwater?

Put simply, whether or not you can drink rainwater depends on a number of factors. Like groundwater sources, the quality of water can vary hugely depending on location, seasonality and geology. However, unlike groundwater, rainwater also brings with it the added complexity of air-borne pollutants. Whilst it starts out relatively pure, rainwater gathers a litany of airborne pollutants on its descent (such as dust, emissions, pollen) and even more once it lands on your roof!

So, drinking untreated rainwater is a no-go. However, with proper filtration and sterilisation, harvested rainwater can be made safe for household consumption. It is, however, important to consider the challenges and drawbacks to rainwater harvesting – which we’ll dive into below.

Challenges With Rainwater Harvesting

Below are some of the most common problems and challenges that arise with rainwater harvesting.

• Contamination Risks: Pollutants from roof materials, bird droppings and airborne chemicals.
• Storage Limitations: Tanks may overflow during storms and high rainfall, or run dry during droughts.
• System Maintenance: Regular cleaning of filters, tanks, gutters and roofspace is vital.
• Legal & Health Standards: Drinking water in the UK must meet strict guidelines set by the DWI.

Additional things to consider include the variability of contaminants and water quality. Due to the enormous number of possible variations in conditions, rainwater is extremely changeable and varies dramatically in quality; therefore the presence of contaminants that require treatment are not always predictable. It can differ hugely not only from place to place, but from one hour to the next. You could test your rainwater one week and find one contaminant which requires treatment, but test it again the following week and find something completely different. It really does depend on several factors. Let’s explore some of these below:

• Seasonal shifts impact levels of pollutants, particularly in urban areas.
• Roofing material matters – lead, asbestos, or painted surfaces can leach toxins into the water.
• Nearby activity, such as agriculture or industry, may increase exposure to heavy metals and chemicals.

Sediment filtration, carbon filtration and UV sterilisation are likely to be required as an absolute minimum, with a possible need for reverse osmosis, depending on whether any dissolved contaminants falling above safe, recommended limits are found in the water.

It is important to carry out regular water analysis to ensure all contaminants are being properly treated and removed if you are going to be drinking the water.

With all of the above in mind, there are some places where rainwater harvesting may be a more feasible solution than others. Here are our recommendations for rainwater harvesting, including where it may or may not work well, an overview of necessary equipment and some of our products to get you started…

Examples Of Where Rainwater Harvesting Works Well:

Setting	Ideal Use
Detached Homes	Garden irrigation, toilets, laundry, drinking (with treatment)
Rural Properties	Livestock, crop irrigation, whole-house water systems
Commercial Buildings	Flushing, cooling, cleaning
Schools & Institutions	Educational projects, lanscaping, toilets

Rainwater harvesting systems operate fantastically well in areas with moderate to high rainfall, where there is ample roof space and users are willing to put in the effort to maintain the setup. However, it may be less viable in other scenarios, such as those outlined below.

Example Rainwater Harvesting Scenarios:

Scenario	Why Not	Alternative
Flats & Small Urban Dwellings	No roof access, limited space	Greywater recycling
Erratic Rainfall Zones	Unreliable water collection	Mains-water, private supplies
Medical Or Clinical Environments	Too risky for sterile standards	Mains water
Contaminated Catchments	Unsafe roof or nearby polluted sources	Mains water or private supplies

How To Harvest Rainwater?

To harvest rainwater successfully, you’ll need an idea of how to collect it. Let’s have a look at some of the core components for building a rainwater catchment system before we explore the best methods for treatment.

• Catchment roof
• Gutters & downpipes
• First-flush diverters
• Storage tank (Above or below ground)
• Overflow system
• Pump (For pressurised systems)

For a catchment roof, it is important to avoid lead, asbestos and painted surfaces, as well as roof gardens, where run off is subject to contact with lots of plants or soil. A first-flush diverter could be a beneficial addition to your rainwater catchment system to divert the initial flurry of soiled water during heavy rainfall.

Once you have the core components in place, it’s time to look at water treatment equipment. Below, we’ve listed some of the best solutions for treating rainwater.

Best Solutions For Rainwater Harvesting

If you require any assistance with determining the best solution for your application, please don’t hesitate to contact a member of our team through our Contact Us page, by phone, or via live chat.

Is Rainwater Safe To Drink In The UK?

To conclude, yes – but only with the correct precautions! Rainwater can be an excellent water source when responsibly gathered and treated. The UK’s temperate climate, with moderate rainfall spread throughout the year, makes it well-suited to rainwater collection. Add to that rising water bills, hosepipe bans, and growing environmental awareness, it’s no wonder more and more households are exploring rainwater as a resource. It can be a fantastic solution as ‘off-grid’ lifestyles grow ever more popular, or just to generally reduce water bills and environmental impact.

However, it is not quite as simple as ‘fill up a water butt and off you go’. In some instances, such as commercial premises, or long-term or holiday rental properties, the advice of your local environmental health officer should be sought. Where private water of any sort is made available to the public as drinking water, there is a range of additional regulations to adhere to.

Above all else, please remember that it is important to carry out regular water analyses and seek professional advice to be sure your hard work pays off in clean, safe and fresh-tasting water.