Rainwater + Hair = ?

Lilliana Diaz
Aug 21
5 min read

You’ve probably heard the passing sayings of rainwater being good for your hair. Or not suspecting anything about rainwater because it simply is “only water?” Well, what if I told you that sometimes your filtered tap water is cleaner than natural rain water? Well sometimes this may be in fact the case! Simply because rainwater is natural, it does not necessarily mean that it is clean and may cause more bad than good in your hair.

What do you mean “more bad than good?”

Well, depending on the environment that you are in, that will control the contents of the rainwater. See rainwater, before hitting your head, may become polluted whether that’d be because of dust, smoke, industrial pollutants, or heavy metals (which are more prone for the first showers of the season to pick up).

Therefore, the rainwater in this area will cause more bad than good, it will have high concentration levels, containing minerals such as calcium and magnesium, and/or sulfur compounds. If these contents are not dried off, then not only will sulfur maintain its new found home on the scalp to cause itchiness, irritation, etc. The minerals will also cause buildup, and lead to brittle, stiff, and manageable hair. Worsening dandruff, and causing your hair to become susceptible to yeast growth on the scalp. As Dr. Bushra Aziz states “Rainwater itself is usually not the main problem, but the pollutants it carries can be.”

How do I know if my rainwater isn’t polluted?

The commonality is if there are extended droughts during the southwest monsoons ("a shift in winds that often causes a very rainy season or a very dry season."), there are higher chances of acid rain.

Some ways you could check if your rain water isn’t polluted would be to:

- Look for daily reports recording the air quality of the area.

- Checking your city’s or state’s website for chemical runoff warnings.

- Or, taking a sample and testing the pH levels and noting any questionable characteristics.

What are “pH levels”?

The letters “pH”, mean a measurement that the pH scale uses. This scale uses pH to determine how acidic or alkaline a substance is from a range of 0-14. These two labels are two extremes used, in order to describe substances. For example, a pH of 7 is neutral, whilst anything less than 7 is acidic, and greater than 7 is basic.

The scalp is naturally slightly acidic with a range of 4.5 - 5.5, therefore rainwater may disrupt the pH balance. And whilst average rain water falling has a pH of 5.5-6.5, rainwater with pH levels below 4 & 3 may cause effects such as acid burns on scalp, therefore damaging hair, making it brittle, weak, limp, and loses its shine.

A Peak Into the Behind The Scenes of Rainwater and Hair:

Everyone has a different level of porosity in their hair, meaning if their hair has lifted cuticles or not, ranging from low to high porosity. High porosity hair individuals have lifted cuticles, meaning that they absorb any liquids or substances applied to the hair, easier compared to low porosity hair. Low porosity hair is less likely to absorb moisture, this expands hair shaft, which leads to frizz, and therefore acting as if it is slicked like glue to your head, and if your hair is styled it then reverts to your natural hair. Once our cuticles lift, smooth strands turn rough when contacting water and humidity. Raising cuticles allows strands to connect with each other more easily.

So, in what way does polluted rainwater negatively affect our hair?

Polluted rainwater may cause effects such as:

● Frizz

● Exposure to even more pollutants

● Falling flat

● Will return hair to natural texture

● Cause dandruff, or make it worse

● Weaken hair

● Tangles

● Trigger irritation

● Disturb the natural balance/may alter scalp pH

● Increase itchiness

● Create dry or excess oil

● Encouraging fungal growth

This is the same reason why experts recommend not to go to bed with wet hair. This is because the longer our scalp stays wet, the greater opportunity for yeast to grow on to the scalp. This is due to yeast and bacteria absolutely thriving in warm and moist environments, causing an itchy scalp and dandruff.

Although, rainwater is soft water, and if clean contains no salt nor harsh chemicals, and is pH neutral. Therefore, if used, then may lather noticeably better rather than tap water, along with no soapy residue, and may even last your hair “so soft” for a few days.

When using clean rainwater, how will it benefit my hair?

Rainwater without minerals or chemicals may not directly help with growth, although it supports healthier hair.

Rainwater assists in removal of:

● Dirt

● Sweat

● Detergent buildup from the scalp which has the possibility to clog follicles and thin out hair strands

Healthy/natural hair:

Will help maintain optimal pH balance
Shows enhanced shine and vitality
Will fight minimum buildup
And the hair will look fresh and healthy

Dry/damaged hair:

Helping prevent further damage
Offering soothing cleansing experience
Help moisture retention
Enhancing softness
More lustrous appearance

Fine hair:

Fine hair would react limp and lifeless to harsh water, and rainwater would cause a more bouncier and vibrant look. Because of the texture of fine hair being lightweight, this then prevents fine strands from getting dull.

Reducing risk of:

Irritation
Discomfort

Whilst tap water with minerals and impurities may worsen health of the sensitive scalp.

Colored/treated hair:

Rainwater would preserve hair color and quality
This pure water may help maintain the vibrant hues of the hair

Curly/coarse hair:

May improve curl definition and reduce unwanted frizz
Making more manageable and stunning curls
Add moisture

Regardless, it’s more efficient to determine if the rainwater has moisturizing properties that can assist with a unique or specific curl pattern.

Oily hair:

Rainwater will not effectively help with extra oil on the scalp, and usually you would need commercial shampoos for oil.

Tap Water:

What it contains:

Chlorine
Magnesium
Calcium
Other minerals

Effects of the contents:

Brittle
Frizzy
Dull

How do I fix the effects of acid rain on my hair?

If you’re trying to fix these effects, use soft water to reverse them by installing a water filter. As well as rinsing your hair with vinegar or lemon juice. By using these weak acids before using conditioner or shampoo, this counteracts the effects. Along with taking vitamins, such as vitamin A, vitamin C, Biotin, and Iron.

But how do I PREVENT rain from touching my hair?

When leaving, use a protective cap, silk scarf, or umbrella to ensure that they do not touch. Although if you do not have any of these, then a leave-in conditioner or hair serum will also help in repelling the rainwater, and minimizing negative effects.

What do I do if I already have water on my hair?

If you want to maintain healthy hair, do NOT put it up, wear a helmet, cap, or ANYTHING that traps this moisture and sweat against your scalp -in other words, let your hair loose. Use a microfibre towel (or if you can’t buy one like me, use a cotton t-shirt), this absorbs more water without ruining the hair texture. Wet hair is also more susceptible to not only damage but breakage as well, so never brush out hair or any natural waves that appear because this will simply only risk breakage, and perhaps a more wayward look. And finally, avoid hair blowing, this will only damage the hair further.

Tips for collecting rainwater:

Avoid collecting the first showers of the seasons. They may be more acidic due to chemicals from smoke, smog, along with other atmospheric pollutants.
When retrieving rainwater, it is crucial to get it as soon as it stops falling. This is to avoid invading elements, such as bugs.
Filter the water through a coffee filter or cheese cloth to remove any debris.
Introduce rainwater slowly to your hair care regimen, to allow hair to get used to and adapt.