Generating Daily-use Water Without Tap Supply — 6 Alternative Sources and a 3-Step Purification Method (Part 5 of 5)

12 June, 2025

When a water outage lasts longer than expected—
If water supply stations run dry or water trucks don’t arrive, even in such worst-case scenarios, there are still small amounts of usable water sources around you.

This article provides:
1. Six unexpected but accessible water sources around the home
2. A three-step method to purify water for daily use
presented in table format. We’ve summarized the necessary items, steps, and precautions so that you can act decisively when it matters most.

Top-fill water purifiers can also be used to generate drinking water during emergencies.

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Three Basic Principles to Keep in Mind

Collect the cleanest water possible.
The less contaminated the water, the easier and safer it is to treat.
Chlorine (household bleach) is essential—but do not overuse it.
Just 2 drops per 10–15 L bucket is sufficient. Excess chlorine causes strong odors and skin irritation.
Use primarily as daily-use water (bathing, laundry).
Secure drinking water from bottled or distributed sources whenever possible. Use treated water for drinking only as a last resort.

“Water Treatment Kit” to Keep at Home

Category	Essential	Nice to Have
Chemicals	Chlorine bleach	PAC coagulant (for settling pond or river water) Only available in large quantities on Amazon. We’ll prepare smaller packages if there’s demand.
Water Containers	Buckets / 10L collapsible tanks	Funnels (100-yen shop ones are fine) Rain gutter diverters
Basic Filtration	Colander + towel/gauze/handkerchief	Brita-type water purifier
Premium Option	—	Portable membrane filters for disaster use

When it comes to chlorine bleach, go with simple laundry-use types only!
Avoid “EX” or “Pro” types—they contain additives not suitable for disinfection.
If nothing else is available, kitchen bleach (e.g., Kitchen Haiter) is acceptable.

Simple Water Treatment Methods

These are basic water treatment methods. Combine them as needed based on the water source.

Step	Purpose	Procedure
① Chlorination	Disinfection Iron precipitation	Add 2 drops of bleach to 10–15 L of water (Less than 1/5 tsp)
② Boil for 3 minutes	Disinfection Chlorine removal	Boil water for 3 minutes on a stove
③ Settling	Separation of cloudy particles by sedimentation	Transfer collected water to a bucket and leave it still for several hours. Use the clearer water on top.
④ Towel/Handkerchief Filtration	Separation of cloudy particles by filtration	Strain water using a colander and towel

Six Nearby Water Sources and How to Treat Them

Legend: ★★★ = Drinkable with disinfection, ★★☆ = Suitable for bathing, ★☆☆ = Suitable for laundry

No.	Source	Collection Tips	Safety	Water Quality & Notes	Treatment Method	Usage
①	Rainwater	Discard first 5 minutes of rainfall before collection	★★★	Drinkable with chlorine disinfection after discarding initial rain	Chlorination	Drinking, cooking, washing hands, bathing, laundry
②	AC Condensate / Dehumidifier Water	Place a bucket at the end of the drain hose	★★★	Keep hose/tank clean	Chlorination	Drinking, cooking, washing hands, bathing, laundry
③	Well Water	Use hand pump	★★☆	Quality varies by surface seepage	Chlorination If cloudy: settling or towel filtration	Washing hands, bathing, laundry
④	Firefighting Water Tanks	Follow administrator instructions	★★☆	Quality depends on tank condition	Chlorination If cloudy: settling or towel filtration	Washing hands, bathing, laundry
⑤	Rivers / Ponds	Collect only clear water	★☆☆	Quality varies by location	Clear water: chlorination or boiling Cloudy water: settling → towel filtration → chlorination	Washing hands, bathing, laundry
⑥	Pools	Good in summer Low priority in cold seasons	★☆☆	Quality changes by season	Clear water: chlorination or boiling Cloudy water: settling → towel filtration → chlorination	Washing hands, bathing, laundry

Shakujii River — surprisingly clear urban stream — Shakujii River near home. While classified as an urban stream, the water is surprisingly clear—suitable for laundry at least.

Understanding Water Treatment

No.	Substance	Potential Sources	Risk Level	Treatment Method
①	E. coli and other bacteria	All sources	★★★	Chlorination, boiling
②	Cloudy particles	Rivers, ponds	★☆☆	Settling → collect clear water Colander + towel Portable filter
③	Iron	Groundwater, fire tanks	★☆☆	Oxidize with chlorine → filter
④	Chemicals	Urban rivers	★★★	Use water purifiers
⑤	Organic matter	Rivers, ponds, shallow wells	★★☆	Cannot be treated at home OK for laundry use
⑥	Nitrogen & nitrogen oxides	Rivers, ponds, shallow wells	★★☆	Cannot be treated at home OK for laundry use

Water Treatment Q&A

Are Brita-style water filter pitchers useful during a water outage?: They can reduce chlorine odor and minor cloudiness, but do not eliminate bacteria. Always combine with chlorination or boiling.
How about portable outdoor water purifiers?: Yes, they can be used. However, depending on the initial water quality, their filters may clog or degrade much faster than expected.
Can faucet-mounted purifiers be used during disasters?: No, they require water pressure and cannot function without a tap connection.
Can I use oxygen-based bleach?: Oxygen-based bleaches do not have disinfectant or sterilizing effects.
Please use chlorine-based bleach (e.g., Haiter).
Is it okay to use kitchen bleach (chlorine-based) instead of laundry bleach?: Kitchen bleach (e.g., Kitchen Haiter) also has sterilizing properties, but it contains surfactants.
However, since the required amount for disinfection is only 2–3 drops per 10–15 L of water, the surfactant level is negligible. If laundry bleach (Haiter) is unavailable, kitchen bleach is acceptable.

Conclusion

This article explained how to treat water using household items to make it suitable for daily non-drinking use. There are a few essential materials and tools, so it is advisable to prepare them in advance before a disaster strikes.

We hope this article proves useful in times when water access becomes critically limited.