The Water I Grew Up In
A personal and inquisitive reflection on six years of living with psoriasis
I had never noticed this until recently, when I took a two-week vacation to my hometown, Sorsogon City, in early June. By then I had already had my fourth monthly biologic shot of Secukinumab, which relieved most of my psoriasis lesions except my legs. During a bath, I first felt a tightening of my skin, and I knew instantly my skin was getting dry fast. After only a few days, my skin turned bright red due to inflammation and it was really painful.
I have had psoriasis since 2020. I say that flatly now, which took practice. For a long time, I say it like I am confessing something. What nobody warned me about this autoimmune skin condition is that the hardest part is not the skin itself, but the project that my skin has become.
I did the whole circuit. Steroid creams in ascending potency, until I learned to be afraid of them causing skin atrophy. Vitamin D analogues. Coal tar shampoo. Salicylic acid. Phototherapy, which meant scheduling my body around a clinic’s hours and a traffic forecast. Methotrexate, and the weekly blood clearance checking my liver enzyme levels. Somewhere in there: the low-inflammatory diets, sunbathing, multi-layer emollients, and the well-meaning relatives recommending supplements and ointments that I know will not work.
I want to be honest about the middle years, too, because shame and inconvenience are the parts that get edited out of health writing. I stayed away from swimming pools and stopped wearing shorts, even at home, to protect my legs. I accepted that my clothes would get stained with blood after a night of scratching myself in my sleep. I stopped getting full-body massages, afraid of being turned away by the staff even after explaining that my disease wasn’t contagious. Yes, psoriasis is a skin disease, which I think understates that it is in fact a disease of being looked at.
At the start of 2026, that was when I tried Secukinumab injections. What I like about this treatment is that it blocks only a specific signal in my immune cascade (interleukin-17, a pro-inflammatory cytokine) — rather than dampening my whole immune system the way methotrexate did.
I will not pretend this was a simple graduation. The treatment required weekly visits to a dermatologist with the right specialization, a diagnosis confirmed by biopsy, and a monthly cost I thought about more than I let on during dinners with friends every few months.
But it worked. It works. Skin I forget about for weeks at a time is a blessing, which is exactly why my experience going back to my hometown began to bother me so much.
Observation vs. Bias
When I got diagnosed with psoriasis, I told myself I am going to treat myself like my own little experiment. Being a scientist myself, I was even slightly curious about it. Over the years, the uncomfortable thing I learned about being the sole instrument in my own study is that I am terrible at it.
I know all the ways I could be fooling myself. Traveling, which I love to do, means less sleep and more stress — both documented psoriasis triggers. Fieldwork at my job means different food, more sun, more heat, more sweat, a different bed, and a different amount of self-care — two weeks at a time, for months at a stretch. Because I am in a new environment, I am paying extra attention to my skin than usual. And when you look harder for something, you tend to find it. Confirmation bias was never a footnote in my experiment but was my leading hypothesis about myself, and it still is.
So I did the thing my generation does when we want to know whether a private experience is a real pattern — I posted about it on social media.
The question was simple: do you notice your skin getting worse in the province versus in Metro Manila? I expected to be told I was imagining it, or that of course the province is better — cleaner air, less pollution, less stress, more sun.
About 16% (17 out of 105 scraped comments) of people said the opposite of me — that is, the province gave them clear skin and Manila’s air and heat and grime were the problem.
Around 22% said they had never noticed anything (23 out of 105) or did not share an explicit yes or no answer.
But a cluster of replies, equal to 62% of comments, converged on a similar experience as mine. Their skin feels healthier when they are in Metro Manila, and the common catalyst they attribute it to: the water.
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Not the polluted air. Not the metro rush stress. Though this is a crowd-sourced hypothesis and not a finding, it was specific, mechanical, and testable — which is more than most internet health theories offer for my personal experiences, so I went looking.
Tracing the water source
Metro Manila and most of the provinces are not bathing in the same kind of water, and the difference is not primarily about quality or cleanliness. It is about geology.
About 94% of Metro Manila’s piped supply is surface water and it comes from Angat Dam in Bulacan, through Ipo-La Mesa, and is treated before being distributed to households. Rainwater collected in a reservoir has not spent much time dissolving rock.
A large share of provincial supply, by contrast, is groundwater: deep wells, barangay-level systems, and private pumps. The water we drink has percolated through rock — and in much of this country, that rock is porous limestone or permeable volcanic rocks. Water picks up what it passes through. Calcium and magnesium dissolved out of that rock are, definitionally, what makes water “hard” — measured in milligrams per liter (mg/L) of calcium carbonate equivalent.
Beyond the measure of hardness
This is the part that reframed the whole question for me, and it is the part the Reddit discussion got wrong.
The intuitive story is that calcium is an irritant — that hard water is somehow abrasive, depositing minerals on your skin like limescale in a pipe. However, this is not what the evidence supports. The best human mechanistic work says that hard water’s damage is done through one’s soap.
Calcium and magnesium ions react with anionic surfactants to form poorly soluble compounds (a surfactant is an ingredient used in soaps to lift away dirt and oil from the skin). These residues do not rinse well. A controlled washing study by Danby and colleagues (2018) found that washing in hard water left roughly 2.8 times more surfactant deposited on the skin than washing in de-ionised water. Softening the water below 25 mg/L largely eliminated the residue.
The retained surfactant is also not inert. It altered protein structure in the stratum corneum, solubilised the skin’s lipids, raised surface pH, produced measurable irritation, and increased transepidermal water loss.
Why the injection does not stop this
The obvious question I had since I am on a biologic that works for me, is why a bucket of water should be able to overrule it.
The answer is that cleared skin is not empty skin. Secukinumab intercepts a systemic signal — interleukin-17 — and it does that job extremely well. But psoriasis leaves a garrison behind. Even skin that looks completely healed still holds onto certain immune cells at the sites of old plaques, sitting there, waiting, in case they’re needed again. The drug can be working perfectly, and a strong enough trigger can still wake those cells up.
There is a number I keep returning to. In a prospective cohort of patients on biologics, genuine breakthrough flares were rare — roughly 1.1% over five years, ten cases out of 882. But when the investigators looked at what those flares were associated with, the two things that recurred were Koebner trauma and severe psychological stress.
I found that oddly consoling, and I want to be precise about why. It means the most likely reading of my Sorsogon trip is not that my treatment is failing. It is that I am handing my skin an insult it was never designed to absorb, twice a day, every time I shower.
Six years in
This is the first time I have written about my disease, reflecting on six years into this experiment. Here’s what those six years taught me: patients notice things first, but noticing is not the same as knowing. We notice them badly, unsystematically, contaminated with hope and dread and bias. But we notice them first, which nobody is monitoring at higher resolution than we are.
The work is not to believe an observation simply because we made it, nor to dismiss it out of hand. It is to take that observation seriously enough to find out whether a mechanism lies underneath it — and disciplined enough to say, clearly, that a mechanism is not yet a fact.
I labor this point because psoriasis does not have a trigger — it has as many triggers as it has patients. For one person it is a streptococcal infection, for another a cold month, a tattoo, or an all-nighter. Mine appears to be hard water. One in six people in my own thread told me the precise opposite of what I had experienced, and I have no grounds to tell any of them they were mistaken — they were not wrong and they were simply not me.
Six years in, this is the part of the illness I did not expect to be grateful for. It made me a better reader. It taught me the distance between this happens to me and this is true, and how to stand in that gap without either flinching or pretending it is closed.
I am going home to Sorsogon next holiday and, like many holidays, my family celebrates by going to a local resort where I will soak my body in the same water I grew up in — though this time I will need to come prepared, so that my skin does not have to pay for it. Whatever that preparation turns out to be, I cannot say yet. What I can say is that I will not let this disease make me choose between comfortable skin and going home.
