My dry skin got worse since I moved here.
We hear this from transplants in Nexton, Cane Bay, and Carnes Crossroads more than almost any other complaint. It usually comes after the showerhead crust and the dishwasher spots. The skin is what gets personal.
Here's what we know about the mechanism, what we don't claim, and what you can actually do with the information.
The Mechanism: Hardness and Soap Residue
Summerville CPW delivers water at about 7.2 grains per gallon (gpg), moderately hard per the USGS scale. Calcium and magnesium in hard water react with soap molecules to form soap scum, a sticky residue that doesn't rinse away cleanly.
That residue sits on your skin. In soft water (1-3 gpg), soap dissolves fully and rinses clean. At 7.2 gpg, the rinse isn't complete. The residue can create a tight, dry feeling, especially after a hot shower.
The same mechanism affects your hair. Shampoo residue sits on the hair shaft and stiffens as it dries. Conditioner coats over it temporarily, but the next wash starts the cycle over.
What We Don't Claim
I'm a water treatment installer. I'm not a dermatologist. I'm not going to tell you that hard water causes eczema, dermatitis, psoriasis, or any other skin condition. I'm not going to tell you that a water softener or conditioner treats, cures, or prevents any medical issue.
Skin conditions have multiple causes: genetics, environment, hormones, diet, medication, stress, and yes, water chemistry can be one variable among many. The relationship between hard water and skin is studied in dermatology research, but it's complex and individual.
What I can tell you is the water chemistry at your specific tap. That's a data point you can bring to your dermatologist. A measurable variable they can factor into their assessment of your situation.
The $60-to-$150-a-Month Soap Question
If you're spending $60 to $150 a month on EWG-rated soaps, shampoos, and cleaning products, here's the variable most people miss: those products are formulated for clean-rinse conditions. The surfactants in a premium plant-based body wash are designed to dissolve in water and rinse off your skin completely.
At 7.2 gpg, they're not rinsing completely. The calcium in the hard water is reacting with the surfactants and leaving a film. You're paying for premium ingredients and getting a sub-premium rinse.
Changing the water chemistry changes the rinse. Most homeowners on conditioned water report using less soap and getting a cleaner result. Individual experience varies.
What a Water Test Tells Your Dermatologist
A free in-home water test gives you three numbers your dermatologist can use:
1. Hardness in grains per gallon, How much calcium and magnesium is in your shower water. The dermatologist can compare this to your previous city's water if you've relocated.
2. Chlorine or chloramine level, The disinfectant type and concentration. Some dermatologists note that chlorine exposure can aggravate existing skin sensitivity.
3. pH, Your water's acidity or alkalinity. CPW water runs about pH 7-8. Skin's natural surface pH is about 5.5.
These are measurable, objective data points. They're not a diagnosis. They're variables.
What Conditioned Water Feels Like
Homeowners who install a whole-home conditioning system on 7.2 gpg CPW water typically notice these aesthetic changes:
Week 1: Shower feels different. Soap rinses cleaner. Skin feels smoother coming out of the shower, less tight.
Month 1: Hair is softer. Less product needed. Shampoo lathers more and rinses more completely.
Month 3: Soap residue is gone. Showerhead scaling has stopped. The baseline is different.
These are aesthetic observations, not medical outcomes. Individual experience varies.
Individual experience; results may vary.
What the Research Says (and Doesn't Say)
Several peer-reviewed studies have examined the relationship between water hardness and skin conditions. A 2017 study in the Journal of Allergy and Clinical Immunology found that hard water increased skin barrier disruption in infants. A 2020 systematic review found inconsistent results across studies.
The scientific picture is mixed. Hard water may contribute to skin irritation in some individuals. It's not a proven cause of eczema or dermatitis. And the relationship depends on many variables: water temperature, soap type, individual skin barrier function, genetic predisposition, and environmental humidity.
What we know for certain: hard water leaves soap residue on skin. Soap residue is an irritant. Whether that irritation rises to the level of a clinical problem depends on the individual.
We don't cite these studies as evidence that a water system treats skin conditions. We cite them to acknowledge that the question is real, the research is ongoing, and the answer is individual.
The Humidity Variable
Charleston's summer humidity peaks at 81% in August with daytime highs of 88-92 degrees. You're showering twice a day. Each shower deposits another layer of soap residue on skin that's already dealing with humidity, sweat, and environmental stress.
The double-shower pattern amplifies the hardness effect. More showers per day means more soap residue accumulation. In a soft-water city, those extra showers don't compound the problem. At 7.2 gpg, they do.
The Conversation With Your Doctor
Here's how we'd suggest framing it:
"I moved from [previous city] to Summerville. My water hardness went from [previous gpg, if known] to 7.2 grains per gallon. My skin symptoms changed after the move. I'm considering a water conditioning system to reduce the hardness. Is that a variable worth factoring into your assessment?"
Your dermatologist will know how to weigh that information against everything else in your medical history.
FAQ: Skin and Hard Water
Does hard water cause eczema?
We don't claim that. Eczema has multiple causes and is a medical question for your physician. What we can tell you is that hard water affects how soap rinses from your skin, and that soap residue is a known skin irritant for some people.
Will a water softener fix my skin?
We don't claim that either. A conditioner or softener reduces hardness, which changes how soap performs on your skin. Whether that helps your specific situation depends on your skin, your condition, and your doctor's assessment.
If You Want the Number for Your Tap
Book a free in-home water test. I'll give you the hardness, chlorine, and pH readings for your specific shower. Bring those numbers to your next dermatologist appointment.
Call or text Jarred at (843) 302-5720, or book at prstnwtr.com/book.