The Findings of an ongoing 3.5-billion-year study
Water
for
Dummies
Read the findings ↓
01
Finding 01
The wellness industry solved water
As if 3.5 billion years of ongoing research and development wasn’t good enough, you can buy a powder to add to it for the low price of $60+ a month to “make it better.” We have machines to restructure it, filters that ionize it, and a few dozen folks online with ~400,000 followers trying to teach us how much to drink, and the optimal time of day to do so.
Water has been in continuous trial for 3.5 billion years, across every organism on Earth. Sample size: everything alive. The findings are holding strong.
It’s water.
You drink it.
That’s what the research says. And you’ll still forget to do it by 3 p.m., even with your fancy water bottle with “by the hour” markers on it, because you’re busy and you’re human, and nobody has ever gotten rich by reminding you to do something for free.
Study record
Subjects
Every organism that has ever lived
Intervention
Water. Taken orally, indefinitely
Control group
None — no alternative exists
Funding
Whatever higher power you believe in
Status
Ongoing · results pending
Study duration in seconds
one hundred ten quadrillion, four hundred fifty-one trillion, six hundred billion seconds, and counting.
Fig. 01a — Long-necked marine reptiles, Mesozoic. Schematic, not to scale. Same water.
Fig. 01b — Duration of trial, drawn to scale from the first evidence of life, with the most recent period magnified for detail. Percentages are of the full 3.5-billion-year bar.
◀ 3.5 Ga — oldest evidence of life
Now ▶
539 Ma
The study — ongoing, involuntary, universal
Every organism that has ever lived, drinking water, without interruption, since the first cell. No control group, because there has never been an alternative, and no end date, because nothing has finished. Hover any interval to read the conditions at the time.
02
Finding 02
Eight glasses a day is not a finding. It is an oversight that got famous.
In 1945, the Food and Nutrition Board of the National Research Council found that a suitable daily allowance of water for adults is about 2.5 liters. In their report, they also stated that most of the water needed each day is already contained in prepared foods.
Food and Nutrition Board, 1945
A suitable allowance of water for adults is 2.5 liters daily in most instances.
Most of this quantity is contained in prepared foods.
Nobody reads the second sentence.
In 2002, a kidney physiologist at Dartmouth went looking for the science behind “eight glasses a day” and published the search in the American Journal of Physiology. He found no studies supporting it.
The number stuck, though. Not because it is easy to remember, but because water companies everywhere profit from you believing you are behind.
Fig. 02 — Where the total comes from
Beverages
Food
03
Finding 03
What the actual number looks like
The National Academies of Sciences, Engineering, and Medicine set an Adequate Intake for total daily water of roughly 3.7 liters (125 fl oz / 15.6 cups) for men and 2.7 liters (91 fl oz / 11.4 cups) for women. Total. That counts everything — water, coffee, tea, soup, milk, and the water inside your food.
It is a population average, not a target. Heat, altitude, body size, activity, illness, and pregnancy all affect your hydration needs. No website has a correct number for you, including this one.
For most healthy adults, thirst is a functional instrument. It fires well before dehydration becomes a problem. The only exception worth knowing is that your thirst signal gets quieter with age, so older adults are more likely to dehydrate without noticing.
3.7 L
Men — total, all sources
≈125 fl oz / 15.6 cups
2.7 L
Women — total, all sources
≈91 fl oz / 11.4 cups
Population average.
Not a target.
Not necessarily yours.
Fig. 03 — Water content by weight, per USDA FoodData Central
Cucumber
95
Lettuce
96
Watermelon
91
Broccoli
89
Carrot
88
Baked potato
75
04
Finding 04
Three things you likely believe that are not true
01
Coffee dehydrates you.
It does not — provided you drink one to two cups a day like the rest of us. Caffeine has a mild diuretic effect, and coffee is mostly water. Water wins in this equation. You can rest easy knowing your morning cup counts toward your total.
02
If you’re thirsty, it’s already too late.
This one is 100% marketing. In a healthy adult, thirst is an early signal, not a late alarm. Grab a glass. Drink some water. You will be fine. You don’t need to chug a gallon of water just because you feel slightly parched.
03
Clear urine means you’re doing it right.
Pale yellow is the ordinary target. Completely clear mostly means you drank more water than you needed a short while ago. Clear all day, every day is the one worth noticing — either you are overdoing it, or something other than water is going on.
Fig. 04 — Urine color and what it means for your hydration
Ordinary range
Clear
Deep amber
05
Finding 05
The water aisle sells twelve kinds of water
The FDA writes standards of identity for bottled water. These are the legal definitions a label has to meet, or the product is considered misbranded. Some describe where the water came from. Some describe what was removed from it. Some mean nothing at all. More expensive doesn’t mean better.
Below are the categories and labels that have legal meaning and those that mean whatever the bottler wants them to.
Defined by where it came from
Artesian water
FDA-defined
From a well tapping a confined aquifer in which the water level stands above the top of the aquifer. It may be pumped; the name refers to the aquifer, not the method.
Spring water
FDA-defined
From an underground formation from which water flows naturally to the surface. It can be collected at the spring or through a borehole tapping the same formation.
Ground water
FDA-defined
From a subsurface saturated zone under pressure equal to or greater than atmospheric, and not under the direct influence of surface water.
Well water
FDA-defined
From a hole bored or drilled into the ground that taps an aquifer. The plainest name on the shelf.
Mineral water
FDA-defined
Not less than 250 ppm total dissolved solids, from a protected underground source. No minerals may be added. Below 500 ppm the label must read “low mineral content”; above 1,500 ppm, “high mineral content.”
Sparkling bottled water
FDA-defined
After treatment, it holds the same carbon dioxide it had at the source. Seltzer, soda water, and tonic water are not bottled water under the rules — they are soft drinks.
Defined by what was removed
Purified water
FDA-defined
Produced by distillation, deionization, reverse osmosis, or another suitable process, meeting the United States Pharmacopeia definition. It may also be called distilled, deionized, or reverse osmosis water, depending on the process used.
Sterile water
FDA-defined
Meets the sterility requirements of the United States Pharmacopeia. This one is for medical use, and it is the only bottle on the list with a real clinical job.
Fig. 05a — The structure
Water. H₂O. It contains one oxygen atom and two hydrogen atoms. Every bottle of water contains it. The differences are what else is dissolved in it and what the bottle label is allowed to say.
No standard of identity
Alkaline water
No legal definition
Alkaline water is water with a raised pH, usually 8 to 10. Two things stand between that number and any effect on you.
The first is your stomach, which sits around pH 2 and is full of hydrochloric acid for reasons that predate the wellness industry by several hundred million years. High-pH water meets that acid on arrival and immediately stops being high-pH water. Whatever you paid for is neutralized before it reaches the part of you that absorbs anything.
The second is your blood pH, which is not open to input. Your lungs and kidneys keep it in a narrow band — the lungs by adjusting how much carbon dioxide you breathe off, the kidneys by managing bicarbonate. A beverage that could actually move that number would not be a wellness product. It would be an emergency.
In 2016, researchers publishing in BMJ Open went looking for evidence on alkaline diets, alkaline water and cancer. They screened 8,278 citations. Not one of them studied alkaline water and cancer. The single study that met their criteria looked at dietary acid load and bladder cancer, and found no significant association. Their conclusion was that promoting alkaline water on those grounds is not justified.
There is nothing wrong with drinking it. It is water. Your stomach will treat it like water either way.
Hydrogen water
No legal definition
Hydrogen water is water with molecular hydrogen gas dissolved in it. As soon as you open the bottle, it starts leaving. Hydrogen is the smallest molecule. An open glass of hydrogen water loses about half of whatever was dissolved in it within a couple of hours. If you buy this, you are buying water with a trace amount of a gas that is actively trying to get out of the room.
While it has no legal definition, hydrogen water has the most research behind it by a wide margin. That research is mostly small, mostly short, spread across a scattered set of outcomes, and often run by people with a stake in the answer. Some found effects. Some found nothing — a year-long trial in older adults with mild cognitive impairment came back flat.
It is not a scandal, and there’s not enough evidence to say it is a scam. It is a maybe. But it’s being sold at retail as a yes.
Interesting is not the same as established.
Also worth knowing: the bacteria in your gut produce hydrogen already, as a byproduct of digesting fiber. Yours are doing it right now, for free, on whatever you had for lunch.
Structured water
No legal definition
Structured water is sold as water whose molecules have been rearranged into a
“superior configuration.” Hexagonal. Restructured. EZ. The devices that do the rearranging use vortices, magnets, gemstones, or infrared, and they run from a few hundred dollars to about twenty-five hundred.
The idea started in a good place. A bioengineering professor at the University of Washington was studying how water behaves right at the surface of certain materials and found it does something unusual. It pushes small particles away, forming a zone that excludes them. That is a genuine observation in a lab, at a surface, under a microscope.
The leap from that to a bottle is where it stops being science.
Here is the problem. The hydrogen bonds holding water molecules together are constantly snapping and reforming. Water forgets its neighbors in about a picosecond — a trillionth of a second. Whatever arrangement was allegedly installed at the factory rearranged itself roughly two trillion times while you were unscrewing the cap.
There is a simpler way to see it. A rigid hexagonal lattice of water molecules is not hypothetical. We have one. It is called ice, and you can tell it apart from water because it does not pour. Anything holding that structure at room temperature wouldn’t come out of a bottle.
A professor of chemistry at UNSW Sydney published an article in 2022 with the phrase “snake oil” in the title. He was not being colorful. He was being accurate.
Whatever is in the bottle is still H₂O.
Fig. 05b — The hexagonal claim, as sold
Raw water
No legal definition
Raw water is untreated spring water, sold unfiltered and undisinfected.
Untreated is the condition that water treatment was invented to correct.
In 1900, in the states that kept mortality records, typhoid fever killed about 31 out of every 100,000 people. Cities began filtering and chlorinating their water supplies. By the late 1920s it was down to about 5 per 100,000. By 1950 it was 0.1. Researchers still argue about how much credit water treatment deserves for the era’s broader mortality decline.
The pitch for raw water is that the source is pristine. The problem is that pristine is not a property of a place. It is a property of a moment. A spring is clean until something dies upstream of it, or until the rain moves something through the soil that was not there last week. Giardia, Cryptosporidium, E. coli, hepatitis A, and norovirus are all invisible, tasteless, and odorless. So is arsenic, which occurs naturally in groundwater in much of the world and is one of the more compelling arguments against the idea that natural and safe mean the same thing.
This is why treatment plants test continuously instead of testing once and trusting the spring. Not because they distrust nature. Because nature is always changing.
Find another water source. It is the only one on this list that can also cost you a week in bed, or worse.
06
Finding 06
When identity ends, the label begins.
Without a standard defining what bottled water must be, the argument moves to the package: what each phrase appears to promise, and what a regulator can actually test.
Fig. 06a — Specimen: one label, annotated
Aqua
Veritas
01 · Glacier-fed
02 · Bottled at the source
03 · Alkaline pH 9.5
04 · Naturally occurring electrolytes
05 · BPA-free bottle
06 · Triple-filtered
07 · Premium ultra
08 · Purified water · 500 mL
Composite specimen. Every phrase is one that appears on real labels; no single bottle carries all eight.
01
Glacier-fed — no standard of identity
Not a defined term. Nothing in the regulation says what a glacier is, how much of the water has to come from one, or how recently it was ice.
02
Bottled at the source — no standard of identity
A fact about where the filling machine sits. All water is bottled somewhere.
03
Alkaline pH 9.5 — a real measurement, no proven claim
The number is testable. What it does for you is not.
04
Naturally occurring electrolytes — no standard of identity
Dissolved minerals. Every bottle of water that has touched rock has them.
05
BPA-free bottle — true, and about the bottle
A claim about the plastic. It tells you nothing about the water inside it.
06
Triple-filtered — no standard of identity
No regulation defines a filtration pass, so nothing defines three of them. A bottler could count the same filter three times.
07
Premium ultra — not sure what this says about water
Unregulated, unmeasurable.
08
Purified water — 21 CFR 165.110(a)(2)(iv)
The smallest words on the label are often the only ones the FDA can enforce. They mean the water was distilled, deionized, or run through reverse osmosis until it met the U.S. Pharmacopeia standard.
Bottled water drawn from a municipal supply normally has to say so on the front — from a community water system, in type at least half the size of the statement of identity, and never smaller than a sixteenth of an inch. The statement of identity is the name of the water, not the brand. Purify it and label it as purified water, or sterilize it and label it as sterile water, and the requirement goes away.
The powder you add to your water has the same problems.
An electrolyte stick pack also has a label. But there is no standard serving of electrolytes, so the category of goods has settled on a range instead, governed by whatever in-house science is being run — and the range of options is enormous. This is largely because these products are sold as supplements, which the FDA regulates but does not review or approve before they go on sale.
Fig. 06b — Common servings of electrolytes, in supplements and in food
Serving
Sodium
Potassium
Magnesium
Sold as a supplement
No standard serving
Stick pack, the mild end
3.6 g · daily-sipping formula
55
250
100
Stick pack, the “serious” end
6 g · sold for heavy sweat
1,000
200
60
Sold as food
Regulated as food
A glass of whole milk
1 cup · 244 g · 88% water
105
322
24
A banana
Medium · 118 g · 75% water
1
422
32
A quarter-teaspoon of salt
¼ teaspoon · 1.5 g
581
0
0
All three, together
Milk, banana, salt — about 60¢
687
744
56
Milligrams per serving. Sodium and potassium bars are scaled to 1,000 mg; magnesium to 100 mg. Stick-pack figures are the published low and high ends of the category; food figures are from the USDA.
The two stick packs differ by a factor of eighteen in sodium. They are the same product category, sold with the same word, to the same person, for roughly the same price. At least one of them is wrong about what you need.
If you have been sweating hard for hours, the serious end is doing something real. If you have been at a desk, you have just paid two dollars for a packet of salt, and your blood pressure will have something to say about it later.
07
Finding 07
You can, in fact, drink too much
Drinking a very large amount of water very quickly can dilute the sodium in your blood. Healthy kidneys clear roughly 0.7 to 1.0 liters an hour — that is a rate ceiling, not a daily target — and trouble starts when you keep going past it. It is uncommon, mostly affecting endurance athletes and people following aggressive water-drinking regimens, and it is serious when it happens.
Some people also need to limit fluids for medical reasons, on the instruction of a doctor who knows their history.
There is no universal number. But you have your body, and it will tell you exactly what it needs. Chances are, it’s a healthy diet, a glass, and a tap.
Fig. 07 — Same sodium, more water
Ordinary volume
A great deal of water, very quickly
08
Finding 08
The Water Bowl Report
A note from Jess, who has spent ten years in veterinary medicine — general practice, emergency, and intensive care — and is now studying at Purdue to become a veterinary technician.
Almost everything on this page is also true for the animal in your house, except it can’t go get a glass of water itself. So the job falls to you.
Fig. 08a — The bowl. Refilled by you, or not at all.
Roughly how much.
A dog needs somewhere near one ounce of water per pound of body weight per day. A 50-pound dog is looking at about 50 ounces, or six cups. Cornell’s Feline Health Center puts cats around four ounces per five pounds of lean body weight — about a cup a day for a ten-pound cat. These are starting points, not prescriptions. They count all the water an animal takes in, food included — not just what leaves the bowl. Heat, activity, age, and diet all move them.
Fig. 08b — A day’s total water, food included · US / metric
≈50 oz / 1.5 L
≈8 oz / 240 mL
Most of their water never reaches the bowl.
Dry kibble runs about 4 to 10 percent moisture. Canned food runs 70 to 80 percent. An animal on dry food is getting almost nothing to drink from its dinner alone. An animal on wet food may have taken in most of the day’s water before it ever walks over to a water bowl.
In a 2025 crossover trial of ten beagles — published in Frontiers in Veterinary Science, funded by The Farmer’s Dog, and written mostly by its own research staff, which you should weigh accordingly — dogs fed dry food drank nearly three times as much from the bowl as dogs fed a fresh, high-moisture diet — and still finished the day with less water in them. The dry-fed dogs landed around 102 percent of their calculated daily requirement. The fresh-fed dogs landed at 141 percent.
Fig. 08c — Same bowl, two very different daily numbers. Schematic, not to scale.
Fig. 08d — Moisture content in your animal’s food
Dry food
4–10%
Wet food
70–80%
Cats are the harder case.
They descend from desert animals and their thirst drive is genuinely blunted. A cat eating only dry food is often running with no reserve — enough for a normal day, nothing spare for a hot one. Wet food is 70 to 80 percent water.
Move a cat from an all-dry diet to an all-wet one, and total water intake roughly doubles, urine volume goes up by about a third, and the cat carries measurably more body water. That does not mean your cat needs wet food. It does mean that a cat on dry food needs water available, everywhere, all the time.
Check the gums, not the nose.
A dry nose means very little. It usually means the heat is on. Lift the lip instead: healthy gums are pink and slick, like the inside of your own cheek. Tacky or sticky gums are an early warning. Some dogs have dark, pigmented gums, where color tells you nothing — on those, pull down the lower eyelid and read the pink there instead.
The skin tent is a late test.
Pinch the loose skin over the shoulder blades and let go. It should drop back immediately. But by the time it visibly tents, you are well past mild — and the test lies in both directions. Overweight pets can look fine when they are not. Senior pets and loose-skinned breeds can look dehydrated when they are fine. Learn what normal looks like on your animal while they are healthy, so you have something to compare against.
Never syringe water into a cat’s mouth.
Fluid can go into the lungs. Offer it. Do not force it.
When it stops being a home problem.
Vomiting or diarrhea that will not stop, no food or water for a day, pale gums, an animal that seems wobbly or absent — or a cat straining in the litter box and producing little or nothing. That last one is a blocked urethra until proven otherwise, the most common emergency in male cats, and it kills. That is a phone call, not a website.
09
Finding 09
Where it actually comes from
Wherever you are reading this, you are likely standing in a watershed — an area of land where every drop of rain runs to the same low place. Yours has a name. It ends in a river, a lake, a reservoir, or an aquifer, and somewhere downstream of you, it is somebody’s drinking water.
Remember, in most of the country the storm drain at the end of your street isn’t connected to a treatment plant. Most people assume it is. It discharges untreated to a local stream, carrying whatever the rain picked up along the way — oil, sediment, fertilizer, road salt, and trash. This can have an outsized impact on the local environment and strain downstream treatment facilities.
There is a reason we don’t wash our cars in the driveway anymore. We like the ducks and fish in our local pond.
Fig. 09a — How a watershed works, anywhere
Rain lands on roofs, driveways, and open ground. Every drop runs downhill, picking up whatever it crosses on the way. The water eventually finds and fills a reservoir, which feeds an intake, a treatment plant, a tower, and a tap.
Where water hangs out.
Hydrologists measure how long a water molecule stays in one part of the cycle before moving to the next. It is called residence time, and it is simply the volume of the reservoir divided by the rate water moves through it.
Almost nowhere is it short. The glass in front of you is holding water that has been somewhere else, for a very long time, immediately before this.
Fig. 09b — How long water stays put. Logarithmic.
The sky
About 9 days
You
7 to 14 days
A river
12 to 20 days
Moisture in soil
Under a year
A freshwater lake
1 to 100 years
Groundwater
≈ 300 years
The ocean
≈ 3,200 years
A glacier
≈ 16,000 years
Deep Antarctic ice
Over 1,000,000 years
Ranges and dots are estimates.
You are the second-shortest stop on this chart. Water spends about nine days in the sky and about ten in you, and then it leaves and goes back to work.
Nothing you drink belongs to you. You are borrowing it, briefly, from a system that will still be running the same loop long after your fancy water and electrolyte subscription lapses.
Fig. 09c — Ours: the Chesapeake Bay watershed, 64,000 square miles
Credit: P. Haggerty, USGS — public domain
The simplest health advice on earth depends entirely on something almost nobody thinks about, and the few who do assume it is someone else’s problem. Nobody wonders whether the creeks and rivers around where you live are in good enough shape to keep bringing you a glass of water.
The Clean Water Project, a 501(c)(3), has been working to correct this since 2003 — a group of conservation scientists and volunteers doing stream restoration, water quality monitoring, conservation easements, plantings, and cleanups across Virginia and Florida. There are countless organizations like them out there — we are simply familiar with them because we live in Northern Virginia.
We are not asking you for anything. We just think you should know whose work is standing between the rain on your driveway and the water in your glass.
Stream restoration, water quality monitoring, conservation easements, plantings, and cleanup.
thecleanwaterproject.org →
Fig. 09d — The route. Our runoff becomes somebody else’s drinking water. Ours arrives from the Potomac, the other direction.
10
Finding 10
Why we made this
Jess spent ten years in veterinary medicine, a lot of it in emergency and intensive care. A striking number of the animals that came through the door were there because of something small that nobody caught early. Chris spent nineteen years in intelligence and cybersecurity, working on problems that were seemingly complicated on purpose.
Between the two of us, we got fairly tired of complicated. So we started a small company that hand-pours soy candles and carries provisions from other makers we can name, while telling you exactly what is in them (Clear Mountain Provisions). One day over lunch, while chatting about the company’s future, we bought this domain as a joke.
But just like when we started our candle company, the joke turned out to have a real purpose. The easiest advice in the world is the advice we all ignore, and the free thing coming out of the wall isn’t actually free — somebody upstream is keeping it clean, and dozens of others are trying to sell us something we don’t need. We owe it to ourselves to watch for the traps of marketing and to preserve our waterways and watersheds.
That is the whole website. There is nothing to buy here. We are just happy you stopped by.
Now. Go drink
some water.