Modern technology helps loads. But just as water from ponds and rivers must be filtered and purified, so must precipitation be treated. And collecting it is just as risky for city survivors as hauling water.
To catch and funnel falling water we have large sets of plastic tarps strung in almost tent-like fashion. It doesn’t take a Phi Beta Kappa to realize that someone is around maintaining and using the device.
Collecting water from rooftops that would normally gush down a drainpipe into a storm sewer is also possible. Use plastic sheets and pipe to direct this water into your holding tanks. No precipitation in a city is particularly sanitary. Catching from rooftops that people may walk on and that may also catch dirt and debris is especially unsanitary. Clean collected precipitation similarly to the way you would treat water from ponds, swamps, rivers, and lakes by using a sand filter rack and bleach.
Except in some particularly sodden parts of the world, rain falls infrequently. Bountiful quantities must be stored when it arrives from the heavens. Plastic barrels weighing about 450 pounds when full are ideal. Do most readers realize how absolutely awful water stored over the long term can become? Thank God few people have to drink out of cisterns these days.
There’s a lot of work to be done here. Try to filter and purify precipitation stored in the blue plastic barrels as soon as possible. Let’s not even talk about water stored 3 or 4 weeks in hot climates that hasn’t already been filtered and chlorinated.
At the first sign of trouble, purchase twice as many large plastic tarps, plastic barrels, and plastic pipes and gutters as you expect to need. All of this is very inexpensive, so there’s no need to skimp or cut corners.
Been there, done that people report that out-in-the-open, obvious water collection systems on roofs, in parks, or in parking lots are virtually as much of a threat to survivor security as sending the young men out with buckets. These collection devices are easily spotted by members of the enemy forces, who quickly learn what this is all about. Many really don’t like it.
Expect them to respond by posting sentries or by tearing up the collection system, if they can reach it. The end result is often predictable, especially when no backup collection supplies are available. You die from lack of water.
Ice and snow are sometimes sources of water for city survivors. Just hope you also have an excellent energy supply. Ice and snow as sources of drinking water are not as effective as we might wish. Very few examples of using ice and snow are on record as sources of supply for city survivors. Once melted, snow and ice water should be treated the same as any other scrounged surface water. Great quantities of often scarce energy are required to melt ice. Humans cannot normally pack in enough calories to continually exist on ice water thawed in the mouth. Ice has to be melted first or users sucking on it for hydration will risk hypothermia. Cold-weather native survivors can only use solid ice when they are on an extremely high-calorie diet of mostly animal fat.
PURIFYING WATER
At the retreat, allow any surface water to stand and settle quietly in covered containers for at least 12 hours. This isn’t always possible, but it is recommended. Is it necessary to mention that water should be brought from an area of as little pollution and contamination as possible?
When the storm sewer discharge is south and north is just as safe, go north. Yet don’t be surprised when this isn’t practical. Even though this may be a time of great exposure, fill each container in as sanitary and chunk-free a manner as possible. Our practical objective is a supply of drinking water. It is nice if it has as few big brown lumps and stringy green things as possible, but the objective is life-giving water. Obviously not much water ends up hauled by the fellow who tarries overlong and is shot.
Great numbers of really slick little water purification gizmos are available, mostly from stores selling to recreational survivors, backpackers, skiers, and cyclists. All work nicely, but are expensive and not really designed for long-term city survival requiring purification of hundreds of gallons.
Using a Sand Filter
For practical survival use, we’ll need a sand filter rack. After the water has settled for 12 hours, carefully pour the top 90 percent of the water through a sturdy fine-weave cloth and then into the sand filter rack. Discard any really scummy settlings. Thoroughly clean the cloth and bucket, setting them out in the wind and sun for a day or two to purify.
Construct sand filter racks by building a box out of 2-x-10 lumber or something equivalent. Fill with coarse or fine sand. Either will work, but of course they will have much different speeds of filtration. Place the sand-filled rack directly over a seamless plastic sheet. Fastening a piece of screen from an old-fashioned screen door makes the process a bit easier and more convenient. This screen must be replaced every 60 days or so. Let’s hope the trouble doesn’t last that long.
The sand-filled rack, which could weigh almost 300 pounds, is placed on a slight angle. The plastic collection sheet slopes down into a clean collection bucket. Water poured through the 10-inch-deep sand gradually seeps through to the sheet and runs into the clean storage bucket.
Several additional maintenance chores are in sight here. Unless survivors have an endless supply of clean, new sand with which to replace that in the rack, they will have to empty the filter once a week to spread the sand in a thin layer out in the sun to purify. Sand in heavily used filters will get disgustingly grody very quickly, especially in humid, warm climates or where first settling is rushed or not done at all. Placing very many green and brown chunks in the filter degrades it faster. Carefully clean and dry the underlying plastic sheet.
There is great discussion about specific water purification methods and chemicals. True enough, most survival stores have material that can kill more little water critters than bleach. If you are so inclined, lay in a large to huge supply of this chemical now Most people, however, are going to have to use common household bleach because that is what is available and what they can afford and find.
Using Bleach
Common chlorine bleach is in a category with pickling salt for city survivors. At the first sign of trouble, clean out your local store of all you can afford, carry home, and store. It is an essential material. Any excess easily becomes trading stock.
Calcium hypochlorite, available in powder form from most plumbing and hot-tub suppliers, is also a valuable chemical for water treatment. Makers of homemade explosives are already familiar with this stuff. You need add only 1 ounce of calcium hypochlorite per 325 gallons of filtered water to purify it. The cost is about $5 per pound or 31 cents per ounce. But, cost aside, it doesn’t keep as well as the laundry bleach. The only way I know to store calcium hypochlorite is to seal it in a heavy plastic bag and then again in a wide-mouth plastic bottle. The best storage life I can get is about 18 months; after that, it swells and is neutralized as a result of sucking humidity out of the air.