Rainwater is naturally distilled water, but it contains far more minerals than you’d find in water that’s been distilled by humans. When someone artificially distills water, they boil everything out of it that isn’t plain H2O.
That leaves you with almost pure water and nothing else, which explains why distilled water presents a slightly unusual flat taste to many people. When cloud systems absorb water from lakes, rivers and the oceans, they take a good portion of the minerals naturally in that water with them.
Clouds themselves are made up of not only water but also dust particles, which help to hold them together. Due to artificial sources of dust, like airplanes, there are also other types of inorganic material in this dust mixture.
Due to the evaporation and condensation cycle that causes rainfall, the water becomes distilled in the most literal sense of the word. You could capture rainwater or melt down snow and use it for many of the same tasks that you’d want to actually distill water for.
The pH of artificially distilled water tends to be different from modern rainfall, however.
Difference in pH and Acidity of Rainwater and Distilled Water?
Distilled water has a pH of around 7.5 while rainwater can be anywhere from 4.3-7.0 depending on the weather conditions and pollution level of your local area. Rainwater has gotten increasingly acidic over the course of years because of increased amounts of sulfur dioxide in the atmosphere.
In a perfectly clean environment, rainwater should only be slightly acidic with a pH that never drops below maybe 5.5 at the least. Usually, it would be closer to that of regular distilled water.
Automobiles and power stations release sulfur that’s absorbed into fossil fuels, which are then taken up into clouds. This causes the formation of acid rain, which became a serious problem in the late 1960s and early 1970s.
You can sometimes see the long-term impact of acid rain by looking at limestone monuments, which can actually get eaten away if the pH of rainwater gets too low. If you were to pour regular distilled water over limestone, then it would eventually absorb it but it would take much longer to do any real damage.
Can I Refill a Car Battery or Inverter Battery with Rain Water?
You can refill car and electric vehicle batteries with rainwater in a pinch, though the rain might be too acidic in many areas to make a habit of this. If you make sure to strain the water to reduce the amount of impurities in it, then you can certainly use rainwater to top off the batteries.
Some companies that manufacture wet cell batteries for use in golf carts and other types of EVs are starting to produce walls that can handle lower pH levels than they’d normally be able to. You may want to clean the water with a slight amount of bleach or a straining cloth before adding to it even if you’ve invested in inverter batteries that are designed to accept rainwater.
In many locations, pollution levels are high enough that this is a concern. Some people have placed clean plastic containers on the tops of their vehicles to collect rainwater that can be used in this way.
Others collect water from a rain barrel or other purpose-made device. This can help to dramatically cut down on the amount of foreign material that makes its way into water, since these containers are designed to stay clean even when exposed to various fluids.
Is Rainwater Safe to Drink?
Rainwater is technically safe to drink, but it tends to contain residue accumulated from industrial pollution that makes its way into storm clouds. When power stations and transportation systems generate exhaust, this makes its way into the upper atmosphere where it becomes part of the natural weather system and could end up in your body if you drink rainwater.
A 2018 study published in the Water Science & Technology journal found that rainwater harvesting systems could satisfy all of the water requirements of a building once they were in place. The researchers involved in this study found that grease and oil traps as well as a disinfection system were needed to make the water safe for human consumption.
However, even after running it through a special anthracite-sand filter, the researchers were still concerned about using rainwater as regular drinking water. They instead recommended that it be used to wash motor vehicles and clean floors.
Interestingly enough, they also recommended that it be used as toilet water! That being said, it does seem that the risk of getting sick from consuming rainwater is relatively low.
Many people around the world rely on rainwater as their sole source of drinking water.
Distilled Water vs Rainwater for Plants
Rain or melted snow is probably the best type of water for your plants. Since it’s naturally full of minerals, it can fertilize plants even if they’re growing in poor soil.
One of the reasons that wild plants grow so large is because they receive a steady supply of rainwater. Artificially distilled water has no minerals in it, so plants will have to make up for them somewhere else.
Distilling water does remove many types of toxins and heavy metals from it, however, which is of vital importance when growing more sensitive plants. If you’re caring for any kind of delicate plant, then you want to make sure that you are distilling tap water.
This is especially true if your tap water is in any way contaminated or contains elevated levels of chlorine. Depending on the rate at which rain normally falls in your area, there’s a good chance that you can simply leave your plants outside during storms to take advantage of the rainfall naturally.
Gardeners who are serious about using rainwater often get a rain barrel or re-purpose some kind of large container in order to collect enough to water all of their crops even when it hasn’t rained in a while.
