Other than ‘drink eight glasses of water a day, there are really no hard rules when it comes to drinking water… Right? Is drinking rainwater directly safe?

Well, if you are considering rainwater as your staple source of drinking water, you need to be sure of its quality.

As rainwater journeys through the air and conveyance system, it is exposed to many impurities and contaminants, such as animal feces, pollen, dust, and heavy metals that can make you ill. Boiling and filtration, coupled with safe collection and storage can make rainwater fit for human consumption.

However, considering the level of impurities in some public drinking water supplies, rainwaters may prove the better alternative. Still, many people cringe at the thought of drinking rainwater. If you want to know how safe rainwater is, how to make it drinkable, and if there are benefits of drinking rainwater directly, read on!

How Safe is Rainwater for Human Consumption?

There’s nothing particularly harmful about drinking rainwater, provided it’s clean. In fact, rainwater is the staple source of drinking water for much of the world’s population.

Still, all that’s clear is not safe. Think of rainfall as nature’s way of cleaning the atmosphere. Sometimes rainwater journeys through heavily polluted air, picking up different chemical contaminants and impurities as it cleans the atmosphere.

The safety of rainwater depends majorly on the following factors:

  • Environment: If you live in an area free of airborne containment such as smoke, dust, and or soot, then the rainwater will be cleaner. If you live near chemical plants, paper mills, or power plants, such areas have unusually high levels of air pollutants, that may end up in the rainwater.  
  • Collection: Even if you manage to get clean rainwater, you’d still have to be mindful of how you collect and store it.  If not collected properly, rainwater can quickly turn hazardous as soon as it hits a toxic roof or meets heavy metal-ridden gutters or piping.
  • Storage: Poor storage can just as quickly make fresh, clean rainwater unsafe for human consumption.

That said unless you live near a hot radioactive site like Chernobyl, smoke, dust, pollen, animal feces, leaves, and soot are the more likely contaminants you will find in your rainwater.

Can I Get Sick from Drinking Rainwater Directly?

Could you get away with drinking a mouthful, even a glass of untreated rainwater? 

Probably, as it all depends on what types of impurities are in the rainwater and how regularly you drink it. If your rainwater contains toxic impurities, there’s cause for alarm. Ingested frequently enough, it causes bioaccumulation of toxic metals in your body exposing you to a host of serious illnesses like cancer, bone damage, and kidney disorder. 

Frequent rain means frequent atmospheric cleanup and fewer impurities to grapple with. But sometimes rain visits other lands, not falling on yours for weeks on end. But as we discussed, rain is nature’s cleanup so when it finally returns, it cleans those impurities and they end up in the water.

If you drink that rainwater directly, you’d be ingesting all of that. If that still has not deterred you, we leave you with this takeaway: Whatever you do, don’t drink rainwater that has run off of buildings with toxic surfaces, or in dirty containers.

How do I Make Rain Water Safe to Drink at Home?

There are a number of ways to make your rainwater safe to drink at home. And the good news is that you don’t need to go all sciency about any of them. 

Boiling

Boiling is by far the simplest, most practical water treatment process. Just getting your rainwater from zero to boiling point should be enough to get rid of the parasites, bacteria, viruses, and other disease-causing elements. 

Filtration

Consider filtering rainwater before boiling it. Filtration will eliminate solid impurities and other contaminants. Just pass your rainwater through a home water filtration system, like a coffee filter, and voila—you have yourself, well… semi-clean water! Remember you’d still need to boil it to make it even safer.

Safe Collection

Another important yet frequently overlooked home water treatment remedy is a safe collection strategy. Consider collecting rainwater directly from the sky into a clean container. This method is much safer than collecting water that has touched the roof, gutters, and/or pipes made of questionable materials.

Letting the collected water sit undisturbed for an hour or two should get debris and other heavy particles settling at the bottom. To make sure the water is free of potentially harmful particles, filter and boil it. 

Fun Fact: If you want to take rainwater treatment a step further, consider refrigerating it. Refrigeration slows the growth of microorganisms in the water. 

How Can I Check for Rainwater Purity at Home?

If you want to tell the quality of rainwater, and whether it’s safe to drink, you can test it yourself at home or have it tested at a state-certified laboratory. Alternatively, you can have a trained person come and test it.  

DIY Method(s)

  1.  Observe: To test for rainwater purity at home, pour a sample into a clear glass. Observe if there are any particles and debris visible to the eye.
  2. Evaporate: You can also use a clean spoon to heat the water until it all evaporates. The absence of residue in the spoon once the water has evaporated, means your rainwater is pure.
  3. Boil: As you boil your rainwater, note its boiling point. If it’s pure, it will boil at 100°C. Anything higher than this means your rainwater is too contaminated.

TDS (Total Dissolved Solids) Meter

TDS meter is a portable gadget used to test for dissolved minerals in the water. Although there are sophisticated, more accurate TDS meters with more features out there, a simple one should tell you the amounts of dissolved minerals or salts in your rainwater. 

While United States Environmental Agency (EPA) does not consider TDS a health hazard but as a Secondary Drinking Water Standard, it recommends treatment when TDS readings exceed 500 parts per million (ppm) of 500mg/L. 

Water Purity Testing Kit

A water purity testing kit comes with reactive strips that change color depending on what is in your water. This testing should capture things like water hardness, pH, and minerals.

Expect your rainwater to have a slightly lower pH than that of public drinking water, thanks to sulfur dioxide and nitrogen oxides in the air, which make rain acidic.

Some kits test for additional contaminants like copper, lead, and calcium. It is however advisable to send a sample of harvested rainwater to the lab for comprehensive tests and to corroborate the results you are getting at home. Laboratory tests are more accurate than at-home tests.

But remember water tests have to be done frequently as contaminants change.  

What are the Benefits of Drinking Rainwater?

The Internet is awash with myths. You’ve probably heard that acid rain causes hair loss, or that rainwater makes your skin glow. While most of these claims lack a scientific basis, drinking clean rainwater can be good for you, overall.

Although rainwater will not make you any healthier than bottled water, it’s a worthy alternative considering the level of impurities in groundwater, which is the source of 50% of bottled water in the US.

Tap water has been shown to contain several impurities and contaminants, from salts, minerals, treatment chemicals, to traces of pharmaceuticals. While the long-term impacts of pharmaceuticals in the water cycle have yet to be documented, excess water treatment chemicals, such as chlorine and fluorides in tap water have been linked with dental and skeletal problems.  

How do I Store Rainwater Safely?

Collected rainwater is as clean and safe as the storage container. For collection, ensure your rain barrel or cistern is properly and regularly maintained and disinfected every 10 days. Be sure also to store your water in a non-transparent container to prevent algae growth.  

Sedimentation is your friend. It’s a natural process that forces heavy particles to settle at the bottom of your tank. This should happen before the water enters the conveyance system, as doing so should eliminate the large particles. Just be sure to give those time to settle and avoid pulling water from the bottom of the tank, as doing so will undo the process.

A floating filter is designed to pull water from the middle of the tank. Consider using one.

Adding bleach and/or chlorine to stored water also prevents algae growth. Just be careful not to go overboard. Adding ¼ teaspoon of bleach (per gallon) and/or 4 parts chlorine (per 1,000,000 parts water) does the trick.

Wrap Up

Forget what they say about people who don’t drink tap water being high maintenance. With rainwater, there’s no shame in insisting it is treated before drinking. Purifying rainwater by boiling, filtering it ensures you drink fresh clean water. While there’re no particular health benefits of drinking rainwater, in some cases it is better than the alternative.