Water And Hygiene · Volume 3
Washing Water and the Shower — What Is Safe, and a System That Works
Introduction
Two questions: whether lake or river water can be used to wash in, and how to build a shower around it without heat for now.
⭐ The short answers are yes, with three specific exclusions — and the system that fits this truck is a $40 submersible pump, because the important design decision is not the pump at all.
⭐ THE DESIGN FINDING, revised: filter everything, including the shower water.
The instinct is to save the filter for drinking and shower on raw water. The arithmetic in vol 2 does not support it. Filtering everything for a two-person weekend costs perhaps 18–26 gallons — roughly forty minutes of unattended dripping, and between fifteen weekends and several thousand of cartridge life depending on which filter is bought. Filter life is not the constraint people assume it is.
🔴 And the strongest argument has nothing to do with cost: two water systems create a failure mode that one does not. Somebody eventually brushes their teeth from the shower bucket, rinses a cutting board in it, tops up a dog bowl, or refills a bottle from the wrong container in the dark. One standard for all water on the vehicle removes an entire category of mistake, and mistakes are what actually make people ill in camp — not the water source.
⚠ What remains true is the flow rate, and it is a hard constraint either way: a shower pump draws about 1.3 gal/min while a gravity filter makes about 0.46. The shower empties a container roughly three times faster than the filter fills it. A 3-gallon shower is about six and a half minutes of filtering for two and a half minutes of water. Pre-filling is mandatory, so a bucket sits in the loop regardless — which is exactly what makes filtering into it free.
3.1 Is untreated lake or river water safe to wash in?
For a healthy adult with intact skin, generally yes. The pathogens that dominate backcountry water — Giardia and Cryptosporidium — cause illness by being swallowed. Rinsing with water containing them is not how people get sick.
🔴 Three exclusions, and they are specific rather than general caution.
1. Do not let the water go up your nose.
Naegleria fowleri — the “brain-eating amoeba” — lives in warm fresh water and causes primary amoebic meningoencephalitis, which is rare and almost always fatal. ⭐ The route of infection is the nose, and only the nose. CDC guidance is explicit that swallowing contaminated water does not cause infection; the organism has to travel up the nasal passage to the brain.
Practically: keep your face out of the stream, do not tip your head back into the spray, and do not use untreated water for anything that flushes the nose. ⚠ This includes CPAP humidifier chambers and any nasal rinse — those get treated water only, and the CPAP is already a reason this build carries a medical-grade standard.
It is a warm-water organism, which makes a shallow, sun-warmed inland lake in August the higher-risk case and a cold Lake Superior stream the lower one.
2. Cover open wounds.
Leptospirosis is carried in the urine of infected animals and washed into fresh water, and it enters through broken skin, eyes, nose and mouth rather than by ingestion alone. It is a genuine risk anywhere animals and standing water meet, and the mud and silt along a shoreline hold it as well as the water does.
Practically: a waterproof dressing over any cut before washing, and let scrapes close before swimming.
3. Never wash in a visible algal bloom.
Skin contact with cyanobacteria causes rashes and irritation, inhaling the spray causes respiratory symptoms, and 🔴 it is dangerous to dogs, which will drink it and lick it off their coats. Scum, paint-like streaks, pea-soup colour, musty smell — do not put a pump in it, let alone stand under it.
⭐ Note that all three exclusions are decided at the source, before any equipment is involved. Choosing where to draw from is the safety system; the shower is just plumbing.
3.2 The shower system
Requirement: hot water later, no heat now, a shower tent eventually, and as little weight and complexity as the job allows.
3.2.1 The pump
Table 1 — The pump
| Option | Cost | How it works | Verdict |
|---|---|---|---|
| 12 V / USB submersible pump | ~$40 | Pump drops into a bucket or straight into the lake; rechargeable, roughly an hour of runtime, around 1.3 gal/min | ⭐ Recommended |
| Pressurised tank (NEMO Helio class) | ~$100–150 | 11 L soft tank, foot-pumped, 5–7 min of good spray | No power needed; another thing to fill and carry |
| Garden sprayer, 2 gal | ~$20 | Hand-pumped, surprisingly effective | Cheapest that works; small capacity |
| Solar/gravity bag | ~$20 | Hang it high, gravity feeds | Needs a hanging point and sun; slowest |
⭐ The submersible pump still wins, but for a different reason now: it will draw from anything. A bucket, a jerry can, or — when washing genuinely does not warrant filtering, such as rinsing muddy boots or gear — the lake itself. Every other option requires filling a dedicated pressure vessel first, which is one more thing to fill, carry and store. The bucket is already in the loop because of the flow-rate constraint, so the pump is the option that adds least.
It is about a pound, it costs less than the fuel to get to the Keweenaw, and it runs off the 12 V system already being built.
3.2.2 The rest of it
A bucket or collapsible container, 3–5 gallon, as the reservoir when drawing from the lake directly is impractical. A collapsible one stores flat.
A shower enclosure. A pop-up privacy tent, typically 7–12 lb. ⭐ Specify it to double as the toilet enclosure — the Water and Hygiene brief covers both, and carrying two tents for two jobs that are never done simultaneously is exactly the kind of weight this build cannot afford.
A mat or pallet to stand on, so you are not standing in the mud you are trying to wash off.
3.2.3 Adding heat later
⭐ Start with the simplest thing that works: heat water on the stove and mix it into the bucket. A gallon of boiling water into three gallons of cold lands close to comfortable, costs nothing, and adds no hardware.
Only then consider the alternatives, in ascending order of commitment: a black solar bag pre-warmed on the roof; a propane on-demand heater; or an engine-coolant hydronic loop of the kind the Overland Expo build used, which is elegant and is a five-figure camper’s plumbing rather than a bolt-on.
⚠ A propane on-demand heater is the usual next step and it has a real hazard: they must run outdoors or in a genuinely ventilated space. A shower tent is not a ventilated space. Carbon monoxide in an enclosure is how people are killed by camp showers, and it is worth stating plainly before the option is attractive.
3.3 Greywater, which is the part that gets done badly
🔴 “Biodegradable” soap biodegrades in soil, not in water. It is still a pollutant in a lake, and the label misleads people into thinking otherwise. Soap in water feeds algae and harms aquatic life regardless of what the bottle says.
The rules that follow:
- Wash at least 200 feet — about 70 paces — from any water source. This applies to the shower, to dishes, and to teeth.
- Use the smallest amount of soap that works, and prefer a plain unscented biodegradable one.
- Scatter greywater over a broad area of soil, or dig a shallow sump, so it filters through ground rather than running back into the source.
- Strain food solids out of dish water and pack them out with the rubbish.
- ⚠ Wet ground and shorelines count as “near water.” The 200 feet is from where the water actually is, not from where the map says it is.
⭐ The 200-foot rule is another argument for the bucket-and-pump arrangement: fill the bucket at the water, then carry the whole shower operation two hundred feet away from it before a drop of soap is opened.
3.4 The system, assembled
Table 2 — The system, assembled
| Item | Approx. weight | Approx. cost |
|---|---|---|
| 12 V submersible shower pump | ~1 lb | ~$40 |
| Collapsible bucket, 5 gal | ~1–2 lb | ~$20 |
| Pop-up shower / toilet enclosure | 7–12 lb | ~$60–120 |
| Stand-on mat | ~1 lb | ~$15 |
| Total | ~10–16 lb | ~$135–195 |
Against the drinking-water system in the previous volume, this is cheap in both currencies — and it consumes no filtered water at all.
3.5 What this volume settles
Raw source water is fine to wash in, subject to three rules that are decided at the source: nothing up the nose, cover open wounds, and never in a bloom.
⭐ Filter everything, including the shower water. Filter life is not the constraint it is assumed to be — a two-person weekend is forty minutes of unattended dripping — and running one water standard for the whole vehicle removes the cross-contamination mistakes that actually make people ill in camp. ⚠ Silt is the real constraint on a membrane, so use a coarse pre-filter and let turbid water settle before it goes near the good cartridge.
Start with a 12 V submersible pump, a bucket and an enclosure. Add heat by boiling a kettle. 🔴 If a propane heater ever enters the plan, it does not go in the tent.
References
- CDC — Naegleria fowleri: infection occurs when contaminated water goes up the nose; swallowing does not cause infection; guidance to keep water out of the nose when bathing, showering or washing the face.
- CDC — Leptospirosis: transmission via animal urine in fresh water, entering through broken skin, eyes, nose and mouth; guidance to cover cuts with waterproof dressings.
- Michigan EGLE / MDHHS — harmful algal bloom guidance: avoid contact, keep pets out, report at
Michigan.gov/HABs. - Leave No Trace practice — wash and dispose of greywater at least 200 feet from water sources; biodegradable soap requires soil to break down.
- Camp shower equipment survey — battery submersible pumps around $40 and roughly 1.3 gal/min; NEMO Helio-class pressurised tanks at 11.4 L.
- Water and Hygiene vols 1–2, this project — the payload case and the drinking-water system.
- Vehicle Power, this project — the 12 V system this pump runs from.
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