Can you drink rainwater?

Is rainwater safe to drink, how to collect it, and how to treat it, from the CDC, EPA, WHO and UK regulators.

In shortUntreated rainwater is not recommended for drinking. The US CDC says rainwater is not necessarily safe to drink without first removing germs and chemicals: it can pick up dust and smoke from the air, bird droppings and dirt from roofs, and metals such as lead or copper from roofing, gutters and tanks. If you do drink it, collect it with a first-flush diverter, treat it (boiling is the best way to kill germs), and test it at least once a year.¹²³

1 minrolling boil kills germs; 3 min above 6,500 ft²

Once a yearminimum testing for germs and chemicals in rainwater you drink³

8 dropsof 5–9% unscented bleach per gallon, then wait 30 minutes²

Is rainwater safe to drink?

Not without treatment. Even when it looks clean, rainwater can contain germs and chemicals that could make you sick, and how risky it is depends on where you live, the season, how often it rains and how you collect and store it.¹

From the air: dust, smoke and other particles can get into rain before it reaches your roof.¹ WHO notes that rain is relatively free from impurities apart from what it picks up from the atmosphere.⁴
From the roof: bird droppings and dirt wash into the tank, especially when it rains after several dry days.¹ Faecal contamination is quite common in samples taken shortly after rainfall.⁴
From materials: asbestos, lead or copper can come from roofing, gutters, piping and storage.¹ Rainwater is slightly acidic and very low in minerals, so it can dissolve metals from the roof and tank.⁴
PFAS: a 2022 review found PFOA in rainwater often far above the US EPA’s 2022 lifetime health advisory (4 pg/L), even in remote areas; the lowest median cited, on the Tibetan Plateau, was 55 pg/L.⁵ For comparison, EPA’s 2024 limit for PFOA in public tap water is 4.0 ppt (4,000 pg/L).⁶

How to collect rainwater

Roof and gutters: clean them regularly and fit mesh or inlet filters over downpipes. Use materials approved for contact with drinking water; bitumen-coated roofs and lead-based paints are not recommended.⁴
First-flush diverter: it sends the first rain of a storm, which carries the most dirt, germs and chemicals, away from the tank.¹ WHO recommends sizing it to the roof and letting it drain automatically.⁷
Tank: sealed and covered, ideally with a lockable lid, with the tap not too close to the ground. Disinfect a new tank, for example with a chlorine solution, before using the water.⁷
Mosquitoes: screen the inlet, or empty a rain barrel at least every 10 days.¹
Keep it separate: do not let rainwater get into pipes carrying tap water, and do not mix it with treated tap or bottled water.¹
Rain barrels are for the garden: the US EPA says not to drink rain barrel water or use it inside your home.⁸ Roof runoff can carry bacteria from birds and other animals and chemicals from roofing.⁹

How to purify rainwater

Choose a treatment that removes the germs or chemicals actually found in your water; test first and ask your health department what to test for.¹¹⁰

Clear it: if the water is cloudy, filter it through a clean cloth, paper towel or coffee filter, or let it settle and draw off the clear water.²
Boil: the best way to kill germs. Bring clear water to a rolling boil for 1 minute (3 minutes above 6,500 feet), let it cool, and store it in clean, covered containers.²
Or disinfect: 8 drops of unscented 5–9% household bleach per gallon (2 drops per litre), stir, and wait at least 30 minutes; double it if the water is cloudy or very cold. Disinfectants work less well than boiling against Cryptosporidium and Giardia.²
UV or sunlight: UV units and solar disinfection can kill germs in clear water but work poorly in cloudy water.² WHO lists solar disinfection and point-of-use chlorination as low-cost options for stored rainwater.⁴
Filters: portable filters do not remove viruses, so disinfect after filtering.² Reverse osmosis filters remove some chemicals, such as lead and copper; check the label for what a filter removes.¹⁰

Boiling and disinfecting do not remove chemicals: water with fuel, toxic chemicals or radioactive material cannot be made safe that way.²

For emergency preparedness in the UK, see the emergency rainwater guide for UK homes (Survivalify).

Rules and guidance

United States: home rainwater systems are not regulated or monitored by officials; test at least once a year.³ EPA does not regulate household cisterns.¹¹ Its municipal handbook says harvested rainwater can be used for drinking where a permit process ensures proper filtration and disinfection.¹² Ask your state or local health department.¹
England: rainwater supplied for drinking, cooking, food preparation or other domestic purposes falls under the Private Water Supplies Regulations,¹³ enforced by local authorities. For a single home, a risk assessment is done only on request, unless the supply is part of a commercial or public activity.¹⁴ Most UK rainwater harvesting systems feed non-drinking uses such as toilet flushing through separate pipes.¹⁵

Bottled rainwater on Waterphile

Richard's Rainwater (USA): not enough published data for a Score yet.

In the US, all bottled water must meet the FDA bottled water standard.¹⁶ Each water page shows the brand’s published analysis and links to it.

FAQ

Can you drink rainwater?

Not untreated. The US CDC says rainwater is not necessarily safe to drink without first removing germs and chemicals, and suggests using public tap water or bottled water for drinking and cooking where possible. If you rely on rainwater, treat it and test it at least once a year.

Is rainwater safe to drink straight from the sky?

Rain is relatively free from impurities when it falls, apart from what it picks up in the air (WHO), such as dust and smoke (CDC). A 2022 review found PFOA, a PFAS chemical, in rainwater worldwide, even in remote areas. Collected rainwater then picks up more from roofs, gutters and tanks.

Does boiling rainwater make it safe?

Boiling (a rolling boil for 1 minute, 3 minutes above 6,500 feet) is the best way to kill germs, according to the CDC. It does not remove chemicals: water with fuel or toxic chemicals cannot be made safe by boiling or disinfecting.

Is it legal to drink rainwater in the UK?

Yes, but in England rainwater used for drinking, cooking or other domestic purposes counts as a private water supply under the Private Water Supplies (England) Regulations 2016, regulated by local authorities. Most UK rainwater harvesting systems supply non-drinking uses such as toilet flushing.

Is bottled rainwater safe?

Bottled rainwater sold in the US is regulated as bottled water and must meet the FDA bottled water standard. Waterphile lists each brand's published analysis on its page.

Sources

Information only, not medical or legal advice. If you rely on rainwater, ask your local health department or local authority. Checked 31 Oct 2026.