Chapter 2
Water Sources and the Treatment Each One Needs
Know your water before an emergency decides for you. Walk your own situation: what is in the house, what falls on the roof, what is under the ground, and what is within walking distance. Each source has a characteristic risk profile and a matching treatment chain.
Municipal Tap and Stored Water
The easiest water you will ever have is the water already in your house. Fill food-grade barrels and jugs before a storm, and remember the water heater (often 40–50 gallons) and the toilet tanks — not the bowls. A tub bladder turns a bathtub into a hundred gallons of clean storage without contaminating it. Stored municipal water usually needs nothing but a sealed, dark, food-grade container and rotation; a small chlorine dose extends it. Never store water in containers that held anything but food, and keep barrels off bare concrete on wood or foam.
Main risks: Low while pressurized. Boil-water notices, main breaks, and loss of pressure change that instantly.
Treatment chain: Store it clean → rotate or re-dose with chlorine → carbon for taste
Rainwater and Roof Catchment
Rain is the highest-volume renewable source most households have. An inch of rain on 1,000 square feet of roof is around 600 gallons. Discard the first several gallons off the roof — that first flush carries most of the contamination — and screen the inlet against mosquitoes and leaves. Rainwater is naturally low in dissolved solids, so it is soft, pleasant, and easy on filters and membranes. Check your local rules; collection is encouraged in many places and restricted in a few. Even if you only use it for the garden and livestock, it takes that load off your drinking supply.
Main risks: Bird and rodent droppings, roof debris, and whatever the roofing material sheds — asphalt shingle runoff and any lead flashing or old painted metal are drinking-water concerns.
Treatment chain: First-flush diversion → sediment pre-filter → filter or boil → carbon → storage
Wells: Drilled, Dug, and Driven
A well is the strongest water position in preparedness — but only if you can lift the water without the grid. A deep-well hand pump installed alongside your electric pitless adapter, or a solar-driven DC pump, is what converts a well from a utility into an asset. Shallow dug and driven wells and sandpoints reach water quickly and cheaply and suit high water tables, but shallow water is exactly the water most exposed to surface contamination, especially nitrate. Get a certified lab test — nitrate, coliform, arsenic, and metals — because well problems are invisible and dose-dependent. Shock-chlorinate after flooding or any work on the well, and retest.
Main risks: Coliform bacteria after flooding or casing damage; nitrate near septic systems, feedlots, and fertilized fields; arsenic, iron, manganese, and hardness depending on geology.
Treatment chain: Lab test first → treat what the test finds → hand pump or solar pump for when the power is out
Springs and Mountain Streams
Clear, cold, and moving water is the best-case wild source, and the one the classic hiking filter was designed for. Collect upstream of trails, camps, roads, and grazing, and draw from flowing water rather than a stagnant edge pool. Do not trust clarity: Giardia is invisible and common in beautiful water. Glacial melt and desert washes carry fine silt that clogs elements fast — settle it out first. In old mining country, filters and boiling do nothing for dissolved metals; that calls for reverse osmosis or distillation, or a different source.
Main risks: Giardia and Cryptosporidium are the headline threats — livestock and wildlife upstream, always. Mine drainage and abandoned mining districts add metals and acidity in some regions.
Treatment chain: Settle if silty → 0.1–0.2 micron filter (or boil) → carbon if taste is off
Ponds, Lakes, and Fish Ponds
Standing water is the hardest common source and the one people most often underestimate. Warm, still, biologically productive water is loaded with organisms and organic matter, which both threatens you directly and consumes chemical disinfectant before it works. A stocked fish pond, a duck pond, or a stock tank in a fertilized pasture also carries a dissolved nitrogen load. Fish waste and manure become ammonia, then nitrite, then nitrate — and no filter, no carbon, no bleach, and no amount of boiling touches any of it. Boiling makes it worse by concentration. If you expect to drink from a pond long term, plan on reverse osmosis or distillation, and never use nitrate-suspect water for infant formula. Avoid drawing water during a visible algae bloom or scum at all: cyanotoxins survive boiling and most filters.
Main risks: Everything biological, plus algae and cyanobacteria toxins, and — critically — nitrate and nitrite where there is a heavy natural fertilizer load from fish, waterfowl, livestock, or manure runoff.
Treatment chain: Settle → pre-filter → filter or boil → carbon → reverse osmosis or distillation if nitrate is present
Snow, Ice, and Glacier Melt
Snow is a water source and a fuel problem. It takes a lot of energy to melt, so start the pot with a little liquid water to avoid scorching, and never eat snow for hydration — the caloric cost of warming it is a real cold-injury risk. Melted snow is not automatically clean, especially at low elevation, near roads, or where animals travel. Dirty ice from a frozen pond is dirty water when it melts. Do keep your filters from freezing: ice ruptures hollow fibers and ceramic elements without any visible sign.
Main risks: Same pathogens as the surface water it becomes, plus hypothermia and dehydration if you eat it directly.
Treatment chain: Melt with heat (never eat it) → treat exactly as surface water
Salt Water and Brackish Water
Sea water is the one case where filtration is not a partial answer, it is no answer at all. Carbon, ceramic, and hollow-fiber elements pass salt straight through, and drinking it dehydrates you faster than drinking nothing because your kidneys need more water than the salt brings to excrete it. Only phase change or membrane rejection works. A stovetop or improvised still with a condensing surface will produce small volumes anywhere fuel exists. A seawater-rated reverse osmosis unit — hand-pumped or motorized, at very high pressure — is the practical answer on a boat or a coastline. Brackish estuary and coastal well water is easier than open ocean but still requires RO or distillation. Do not mix seawater into fresh to 'stretch' it; that ruins both.
Main risks: Salinity around 35,000 ppm dissolved solids — roughly seventy times the 500 ppm drinking-water guideline — on top of ordinary biological risk.
Treatment chain: Desalinate first: distillation or seawater-rated reverse osmosis → then disinfect and polish
Map Your Own Water
- Count what is already in the house: stored jugs, barrels, water heater, plumbing, canned goods.
- Measure your roof area and figure out what one inch of rain would give you.
- Know whether you are on a well or a municipal main, and how you would lift well water with no power.
- Identify the nearest surface water and walk the route. Note distance, elevation, and how you would carry it — eight pounds per gallon adds up fast.
- Match one treatment method to each source, then add a second, different method as backup.
Frequently Asked Questions
- Is well water safe to drink without treatment?
- Sometimes, but only a certified lab test can tell you. Private wells are not regulated like municipal supplies. Test at minimum for coliform bacteria, nitrate, and arsenic, and retest after flooding, after any work on the well, or if taste, smell, or clarity changes. Treat according to what the test finds rather than treating blindly.
- Can you drink pond water if you filter it?
- A 0.1–0.2 micron filter makes pond water biologically much safer, and boiling or a purifier closes the virus gap. But filtration does not remove nitrate, nitrite, pesticides, or algal toxins. Ponds with fish, waterfowl, or livestock runoff often carry high dissolved nitrogen, which needs reverse osmosis or distillation, and water with a visible algae bloom should be avoided entirely.
- Is rainwater safe to drink?
- Rain itself is clean; the roof and gutters are the problem. Divert the first flush, screen out debris and insects, then filter or boil and polish with carbon. Avoid drinking runoff from asphalt shingles, treated wood, or old painted or lead-flashed metal roofing, and check local collection rules.
- How do you get drinking water from a well without electricity?
- Install a deep-well hand pump alongside your electric pump, use a solar-powered DC pump, or drop a slim stainless well bucket down the casing on a cord. Shallow water tables can also be reached with a pitcher pump or a driven sandpoint well.