rainwater collecting

February 11, 2005 9:59 AM

rainwater harvestingAs posted on metaefficient Aaron up in the northeast has his own home based business producing rain harvesting barrels It seems like an idea we all should consider doing. A rain barrel is a rainwater harvesting system that is connected to a down spout tube from a house or building. We make quality rain barrels that collect, store and divert rooftop runoff during a rain shower.
posted by halekon (22 comments total)

I don't know if I'd want to drink the rainwater that falls in most major metropolitan areas...
posted by mullingitover at 10:10 AM on February 11, 2005

My dad waters his half-acre garden with collected rainwater. (Their municipal water supply is full of salt and chlorine.) It's really cool.
posted by mudpuppie at 10:24 AM on February 11, 2005

These are very common here in Santa Fe. All my downspouts have them. I can hook a powerwasher up to the rainbarrel and wash my car with rainwater. Other people have them piped to undergrand storage tanks and filtering systems.
posted by Qubit at 10:53 AM on February 11, 2005

Depending on the use to which you will put the water, you'd also want to consider a stable (i.e. non-leaching, non-reactive) surface to your roof, otherwise you'd be collecting all the chemical crap of the shingles/tiles. There are enamalized crinkly-tin rooves for this purpose, but I think they're quite expensive. I had friends who recycled roof water for gray water (washing, garden/vegetables), and they had to install the expensive roof.
posted by carter at 10:57 AM on February 11, 2005

I am a US citizen that now lives in Bermuda (married to one). Every house here collects rainwater off of the roof into a tank built into the house (usually a concrete/limestone basin underneath the house). It is key in your roof design to make it so that it isn't too steep so that water overruns the system's ability to collect water in a hard rain.

Many houses here these days either use a Brita filter for the water, or they have in-house filtration systems in place which usually reside in a closet somewhere and filter the water on an as-needed basis.

Toilet water is generally a waste of drinking water, so if your house is near well water, then it is best to pull from that for your toilet in order to conserve water. You can't filter (at least not easily/cheaply) that water since it is full of silt and more importantly is brackish.

If the power goes out (common in hurricanes), then we can't pump the water out of the tanks, so it has to be done one bucketful at a time by hand unless you have a generator to run your pump.
So if the power is out, you may have a gas stove and some battery powered lights, but no water. No showers, no drinking, and to some degree no toilet. (if you know the storm is coming, then you plug up your bathtub and fill it with drinking water, and then when your toilet is at its worst, you fill a bucket with water and use that to flush)

All of the fun stuff that I never had to think about living in Boston.
posted by MrFancypants at 10:57 AM on February 11, 2005

I don't know if I'd want to drink the rainwater that falls in most major metropolitan areas...

You can use it for flushing toilets, water the garden, washing your car etc.

The average North American uses about 350 litres per person per day. That's a lot of water, and only a small part of that is actually used for consumption. If you substitute recycled rainwater for uses that don't need purified, chlorinated water you save a lot of water from the aquifiers. Because they will dry up some time and then ther will be draught.

Ah well, of course then the US will invade Canada, with it large resources of fresh water.
posted by kika at 10:59 AM on February 11, 2005

Cool idea. I wonder how this can be used in conjunction with green rooftops.
posted by DakotaPaul at 11:12 AM on February 11, 2005

Wow - 31 words of your own, and 5 of them misspelled (nosted, metaefficeinet, Arron, harvesing, barrell). Is it too much to ask that you might run "Spell Check" before posting an FPP?

BTW, almost every dwelling on Bermuda employs rainwater harvesting because, I believe, Bermuda's geology does not lend itself to the formation of an aquifer. This may be common with small & volcanic islands, although I know Hawaii (the big island) has an aquifer but it is very deep, requiring wells that are thousands of feet deep.
posted by kcds at 11:15 AM on February 11, 2005

kcds, already on MeTa.
posted by knave at 11:19 AM on February 11, 2005

When Maryland faced a drought a few years back, we weren't allowed to use water to wash cars, water gardens, etc. We were encouraged to use water sparingly in our homes, too.

I got in the habit of keeping a bucket in the bathroom. When running the water for my shower, I stuck the bucket under the faucet to catch the cooler water while the shower was warming up. I used that water to flush the toilet, water my indoor plants, fill the kitty water bowls, and any number of other things.

I have always thought that there should be an attractive way to capture rainwater. I've sent this linkie to my bro-in-law; he builds homes in Texas.
posted by Corky at 11:34 AM on February 11, 2005

Corky, here's an attractive one outside of Austin.
posted by mudpuppie at 11:51 AM on February 11, 2005

It's a wonderful idea of course, especially for those of us that live in drier areas, but the water laws here in Colorado preclude the use of them. Not that there aren't people that have them, it's just something that isn't strictly enforced... yet.

Also, those tanks that are used for collecting the rainwater? They're known as "cisterns".
posted by Eekacat at 12:06 PM on February 11, 2005

Mmmm... Just think of all the birdshit on your roof right now.
posted by delmoi at 12:11 PM on February 11, 2005

Rainwater collection was pretty common practice where I grew up in Hawaii (the Big Island). Rural areas generally didn't have county water so most folks living out in the sticks on the east side had a water tank fed from their roof. Tanks would range from 5,000 to 10,000 gallons for a single family dwelling. A school I went to had a 20,000 gallon tank. They fill up pretty quickly during the rainy season and typically last the year. We had filters and a purifier on taps used for drinking, or just bought bottled water. We weren't worried about bird shit, so much as mercury or other gases in the air from the volcano. Once in a while there was a drought and we had to hire a water hauler to fill the tank, but normally it worked out fine. One problem, volcanic islands are prone to earthquakes. The first tank we had collapsed during a 6.5 tremblor.
posted by MetalDog at 2:17 PM on February 11, 2005

We just used 55 gallon trash cans.
Granted, that doesn't sound as cool as a "rain harvesting barrel" but it did the same job.
Even satisfied this requirement:
We do not know of any other rain barrel that connects directly to a gutters down spout yielding 100% of the water from your rooftop like ours do.
A lot cheaper too.

Eekacat - Why would they be illegal in CO?
posted by madajb at 2:31 PM on February 11, 2005

An interesting explanation of Bermudian architecture designed to catch rainwater, with more on the island's underground water sources, called lenses, as well. Some photos here.
posted by beagle at 2:32 PM on February 11, 2005

madajb, if you're asking for a logical reason, I have no idea. Apparently we don't own the rights to the water that falls from the skies onto our property. Something about collecting "runoff" I suppose.
posted by Eekacat at 4:08 PM on February 11, 2005

Strange cultural effects going on here - here in Australia, there's probably as many homes with rainwater tanks (what we call those fancy "barrel" things) than without, even in cities. It's just what you do. Yet there seem to be a lot of people here saying "wow, what a novel idea!". It's kind of a strange cognitive dissonance!

In regards to the safety of stored rainwater for drinking, though, it's perfectly fine. One simple thing that can be done to improve it though, especially in dusty or polluted areas, is to install a "first-flush diverter". When it starts to rain, for the first few minutes, the water from the roof is diverted to wastewater because it's basically washing all the dust and grime from the roof. After that, the pure water is stored in the tank.

As for not owning the rights to the rain that falls from the skies onto your property - I find that an amazing concept. If you don't own it, who does?
posted by Jimbob at 4:46 PM on February 11, 2005

There are tons of resources on the web if you're interested in making your own. I'm not unhandy but I don't make things that often, and I was able to put together a nice rain barrel out of a big plastic trash can and a bit of hardware. It filled up with the first major rainstorm and I never came close to emptying it when watering our modest vegetable garden. Here are the directions I used.
posted by sudama at 6:21 PM on February 11, 2005

Jimbob: Yep, it's pretty amazing. Eekacat is right. I moved to Colorado a few years ago from California (where I took 2 quarters of water politics courses at my university), and I still still shake my head at water law here.

Basically all water, aquifers, surface water, and rainwater/runoff belongs to the state. You can use it only if you own a water right. These are essentially property deeds that allow you access to a specific amount of water from a specific location. They are ranked by seniority, so in a drought, if your deed was drawn up first, you get to claim all of your water before any of the less senior water rights do. Also, NO water can be left 'unclaimed'... (that would be 'wasteful'), so all water ends up being owned by *someone*. Technically, even directing your gutter downspout toward your garden is illegal here.

Ick. Honestly, just thinking about it makes me want to get my own rain harvesting barrel, as an act of civil disobedience.
posted by zeypher at 9:41 PM on February 11, 2005

Jimbob: when I installed my 5000 litre kitchen tank, I looked at commercial first-flush diverters and was amazed that such a simple idea seemed to need balls, seals, springs, stainless steel and expensive engineering.

What I use now is very simple and was very cheap to make.


     ////////////////////////////////////////////
    /////////////////roof///////////////////////
   ////////////////////////////////////////////
  ______________________   ___________________
       gutter           | |    ________
                        \ \   /  ______--> to tank inlet
                         \ \  | |
                          \ \ | |
                           \ \| |
                            \   |45 degree junction
                             \  |
                              | |
                              | |
                     downpipe | |
                    2700x90mm | |
                              | |
                              ~ ~
                              ~ ~
  collector 6000x100mm        | |
 _____________________________| |
[_______________________________/
^
| end cap with weep hole


The water can't go uphill from the junction to the tank until the collector and downpipe have backed up, so the first-flush gunk settles on the bottom of the collector pipe instead of the bottom of my tank. Together, the collector and downpipe hold about 70 litres. The weep hole empties the whole arrangement in about four hours. Nice and simple, no moving parts, and the water that weeps out the end is gunk-enriched for the garden. I remove the end cap on the collector pipe every couple of years and hose it out.
posted by flabdablet at 5:32 AM on February 12, 2005

These things are bsolutely Ubiquitous in the Uk too, where, despite popular misconceptions, we do sometimes have inadequate rainfall. In fact, I heard the other day that some areas of London and the South East recieve so little rainfall that they are technically desert. As I live in London, perhaps it is time I bought a camel as stylish, green alternative to an SUV.
posted by rhymer at 4:38 PM on February 13, 2005