Drinking Water: Rain or City?

I’ve been trying to figure out how to get drinking water lately. I had the Alto Pass Water District come out to give me an estimate of what it would take to get water to the farm, and that’s not looking very promising. I’d have to have them bore under the road, then I’d have to do all sorts of paperwork to get an easement (this paperwork is actually the thing that I want to avoid the most), and then I’d have to dig a trench and lay plumbing all the way up to wherever I want the water, which means about 800 ft of piping.  So, it’s expensive, and it also has a lot of continuous costs, whereas harvesting rainwater is pretty much cheap all the time (except in a drought when I might have to haul in water, but I did some calculations, and I should have much more water stored than I could possibly use for drinking; note that I’ll also have water from the pond for some things, like watering plants).

So then, how do I make a rainwater harvesting system? Let me begin by saying that the cabin (or, if you prefer, shack) has an asphalt shingle roof that is roughly 13 ft by 17 ft. Alto Pass has an average yearly precipitation of 48 inches, and asphalt shingle roofs have a collection efficiency of roughly 85%. There are some problems with asphalt shingle roofs being used in water harvesting, namely, they have a tendency to leak petroleum-like chemicals and grit into the roof runoff. That being said, there are solutions: first-flush systems and filters.

A first-flush system discards the first few liters of water, because that is the water that is going to contain most of the bacteria and bird/animal feces from the roof, grit and petroleum-like chemicals from the asphalt shingles, and other pollutants from the air (this sounds kind of goofy, but the first rainfall will contain the most suspended airborne pollutants, with the air being dirtiest after a long dry spell: the rain effectively cleans the air; sorry for not including the original newscientist paper, but it’s behind a paywall). My first-flush system will likely be as in the following picture. tipping_gutter_first_flush The water comes from the downspout into a gutter attached to a pulley, with the other half of the pulley attached to a bucket with a very small hole in it.  As the water comes off this gutter, it is diverted into the bucket, but this extra weight eventually pulls the bucket down and consequently positions the gutter so that the water can empty into the tank. The reason for the hole in the bucket is that it will drain slowly and automatically reset for the next rain.

My filter charcoal_filteris going to be as in the picture. The charcoal layer is activated charcoal, which does a good job of clearing out organic compounds. There is one potential problem with that, namely, that the activated charcoal can become a host for bacteria, but I’m planning on remedying that in two ways: (1) changing the charcoal relatively frequently and (2) using chlorine if necessary. I suppose a third way might be to have a smaller, immediate-use-type filter, like a Brita pitcher, but I think that’s rather unlikely for the time being. The other filter layers are pretty much self-explanatory and don’t need any additional comment.

In writing a preliminary version of this to a friend, they asked if I was concerned about acid rain. Eh, not so much. Even if I were, I think that it’d also be a problem for my city water source, because acid rain frees heavy metals from the soil and Alto Pass water comes from a big pond. In any case, I’m going to include a little bit of limestone in the water to make it a little more basic, because acidic water tends to have more soluble heavy metals and pesticides. As mentioned above, I may also have to add a little bit of chlorine to my water to kill any bacteria in it, but I’m going to wait on that. I want to test the water first and not introduce chlorine if I don’t have to. Or I may just rely on the hygiene hypothesis


  1. Leonard Maltin said

    How about a Romanesque aqueduct system all the way to the Mississippi? Otherwise, the rain collection system seems pretty great – when are you building it?

    • Nathan said

      I think I’d have to have an aqueduct system that stretched all the way to north of Minneapolis, because I’m on high ground for Illinois (like 800 ft) and I’m pretty sure that aqueducts are gravity driven. I’ll start building it as soon as I get the cabin (do you see that Rev. Transit?) moved to it’s permanent location, which should be in a week or two.

  2. “the cabin (or, if you prefer, shack)”

    It’s a shed. It was built to store tools, not even livestock.

  3. Sam Guard said

    The house I lived in as a child (ie FDR’s first administration) had a rain water system. It collected water from only the steep slopes of the attic roof, but not the flatter porch and single story additions. the gutter downspouts (two, one at each end of the house) emptied into a large (24″x30″), covered title cylinder filurveled with charcoal brickette, pebble-sized (ie 1/2 to 2″, not cobble at 3 to 10″) gravel, and course “bank” sand (not fine “beach” sand). Water from both rain barrels was gravity piped to a buried concrete cistern where it was easy to hand pump into our first-floor kitchen spigot, or basement laundry. The water was always refreshingly cool and sweet tasting.
    I believe that if you do not allow the water in your tank to rise above 55-degrees F. you will reduce the bacteria level significantly. It is…SEE MORE

  4. Sam Guard said

    CONTINUED….a logarithmic curve, so a small change makes a big difference.
    Air Quality & First Flush: Last year on my back porch 17 feet above ground level in Hyde Parkn the “Particulate Matter” sampled at 15.6 micrograms per cubic meter, or almost exactly the EPA’s national “average.” of 15mg/cm. In the past, we have had twice as much here. Most of it, I think, is insoluble in water, and cause haze, smog, and global warning (to some extent).
    Enjoy your adventure to the fullest ?

    • Nathan said

      Hey Sam, thanks for the thoughts on the rain collection. I’m eventually going to be putting in a cistern, but that’s quite a ways off. I didn’t know about the water temperature in the tank. I don’t think I’ll be able to keep it that cold, because the ground temperatures here are a little warmer. Too bad… but yeah, I’m definitely enjoying this immensely. It feels like the proper pace of life.

  5. sam
    thank you about your details in rain water system now i never wonder about rain water system,,

    thanks sam

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