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Rainwater collection, anyone?
Last Post 08 Nov 2012 01:26 PM by MSG79. 108 Replies. |
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ICFHybrid
Veteran Member
Posts:2126
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| 27 Sep 2011 10:14 PM |
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Is anyone collecting rainwater from their roof? I'm thinking about more than just a "rainbarrel", because I'm interested in how you piped the downspouts to the cistern and how it is working for you.
And, I guess the question sorta assumes buried cistern.
Type and size of pipe? Burial depth and slope? Cleanouts? Fittings? Any problems over time with buildup of anything or clogging?
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Lee Dodge
Advanced Member
Posts:550
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| 27 Sep 2011 11:02 PM |
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I was interested in considering one here until I found out that it was against the law in this town. Colorado has some strict water laws, the basis of which I do not understand.
I had a friend in another city who was on a very tight budget, but put an above-ground system together for her house. It consisted of a large black plastic tank (black to keep out light and avoid algae growth) that I think was 5,000 gallon capacity. Being tight on funds, she used women's hose to filter the water. She used the water only for watering plants, so water quality was not critical. Her system might have used 4" PVC pipe to go from the downspout into the tank. Being above ground might have made the tank easier to clean out, but also not practical for esthetic reasons for most folks.
Some more sophisticated systems use a diverter for the first amount of water, assuming that it will contain more debris from the roof and gutters.
I think you have a neat idea, and sorry that I do not have more info to share. |
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| Lee Dodge,
Residential Energy Laboratory,
in a net-zero source energy modified production house
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bpnkrtn
New Member
Posts:54
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| 28 Sep 2011 02:40 PM |
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I lived with rainwater as my only water for 10 years. It was a homemade system that was a sterling example of how to do things wrong .... but it worked for us (3, then 2 people.) I had 2 1500 gal tanks beside the house with 4 inch PVC pipes deliverying water from the 'Lowes' plastic gutters. Right at 1700 sq. ft. of roof surface (you get 624 gallons/1000 sq. ft./1 inch of rain minus losses such as leaks, overflow in intense events, and the first flush diverter.) Tanks were above ground and we never had freezing problems with a few 10 to 15 degree nights ... but not often that low. We used a Big Berkey to filter our drinking water and did not drink from the tap ... but did brush teeth, etc. from the tap. Since we were off grid I placed a 1250 gallon tank on a ridge, about 100 feet higher than the house and used gravity feed. We pumped when it was sunny :). The bottom tanks did get a layer of "stuff' in them and you had to be careful not to stir it up. We never had odor problems until a rat went up my overflow pipe and committed suicide in the tank. There was little information available when we put our system in, in 1999. There is a lot of information and data available now, especially at ARCSA.org .... American Rainwater Catchment Systems Association. This was in upstate SC with an average annual precipitation of 60 inches. But it is common in Texas in areas that get as low as 20 inches. NOTE: I would use paragraphs if this editor would let me!! |
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bpnkrtn
New Member
Posts:54
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| 28 Sep 2011 02:43 PM |
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I will add that some of the best equipment, as in first flush diverters and trash filers come from Germany or Australia ... they are worlds ahead of us in the technology. Of course you don't need a lot of technology for a baseline, functional system as I described above. Good luck. |
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Springtime
New Member
Posts:20
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| 28 Sep 2011 06:41 PM |
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Ive built two simple ones for about 500$ including my time for labor. A local farm and container shop has 275g tanks for 120$. First flush diverter is a 24" long wye leg with a 2" ball valve. Not buried but very ideal lots with gutters and tank location above everything else on the lot and it only serves for garden and landscape. Actually just blogged about it w a pic: http://www.springtimehomes.com/asheville-builders-blog/?p=10
I recently got a bid for a buried 2500g system to supply bibbs, toilets and washing machine for 6000$.
Lee, Ive never heard of rainwater catchment being illegal. Do you mean for use indoors? |
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Lee Dodge
Advanced Member
Posts:550
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| 28 Sep 2011 07:27 PM |
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Brian-
Concerning Colorado water laws, from http://www.groovygreen.com/groove/?p=3850:
"If you live in the city, don’t install a barrel under your gutter spout just yet. The legislation lets residents on wells collect rain and establishes 10 pilot projects for new developments. Residents on municipal water still can’t legally collect rain, and water suppliers are leery of legislation that would let them. 'All the water was spoken for here in the Arkansas Basin 100 years ago or more,” said Kevin Lusk, water supply engineer for Colorado Springs Utilities. “If the water falls as rain, that’s water that was going to get to the stream system, and somebody already has dibs on it, and if somebody intercepts that, it’s the same as stealing.' ”
I am in the Arkansas River Basin, and I have been told that it is illegal to collect rainwater here. I neither understand nor try to defend Colorado water laws.
On another note, did you ever work at UTRC? |
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| Lee Dodge,
Residential Energy Laboratory,
in a net-zero source energy modified production house
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Springtime
New Member
Posts:20
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| 29 Sep 2011 11:25 AM |
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Incredible!!!
I knew western water politics was screwy but WOW!
I did not. |
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bpnkrtn
New Member
Posts:54
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| 29 Sep 2011 11:32 AM |
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The US has two areas that differ in state water laws. East vs. West, Wet vs. Dry, Abundant vs. Scarce. As a broad generalization it's Spanish vs. English water law. As water resources become more scare, and the price goes up accordingly, it gonna' get stranger ... IMO. |
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ICFHybrid
Veteran Member
Posts:2126
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| 30 Sep 2011 10:04 AM |
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The bottom tanks did get a layer of "stuff' in them and you had to be careful not to stir it up. I am interested in the layer of "stuff". Earlier, you mentioned "first flow diverter". Did you have one and what was it like, i.e. how was it constructed and what portion of the flow did it divert before collection? Did you clean it religiously, just when it was full or what? Sounds like the layer of "stuff" was at the bottom, or was there a floating layer, too? Was the bottom layer fluffy and essentially suspended, or was it more silty and compact? What kind of a roof did you collect from? |
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ICFHybrid
Veteran Member
Posts:2126
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| 30 Sep 2011 10:38 AM |
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I recently got a bid for a buried 2500g system to supply bibbs, toilets and washing machine for 6000$ You may have already discovered this, but sizing the tank is a bit of an adventure in itself. I initially spec'ed the 2500 gallon underground tank because it was the largest you could get that was suitable for burial and potable water. The problem is that it is a fairly rare beast. Because of it's size and shape, it is difficult to freight and costs are high. I was prepared to pay the higher tank price, but when I went to order, I discovered that the additional freight was, in fact, substantial. The total costs ended up being something on the order of 3X-4X the next largest (regularly stocked) size of 1750 USG. At that point, we needed a pause to re-evaluate. I worked over my need calculations based on expected rainfall and historical data showing the longest time between substantial rain and decided that 1700 gallons would just be sufficient. I didn't want to have to mess with a refill system should the tank approach dry. Of course, the first thing the very knowledgeable salesperson told me when I went to order the 1750 USG tank was "You are aware that only 1500 gallons is usable, right"? Heh heh. Back to the drawing board. One of the options was now to buy two of the 1750 gallon tanks and pipe them together. That would have made a mighty storage capacity of 3000 gal (usable). The smaller tank was so much cheaper than the original 2500 gallon tank planned, that doubling the price wouldn't have busted the budget (much), so that started a re-consideration of the original tank. ALong the way, I found that the 2500 gallon tank also had a more limited usable capacity, and the idea of paying so much more for only a few hundred gallons began to rankle...... Ultimately, I got just a single tank rated at 1750 USG. This particular type of tank didn't seem well-suited to piping together with another tank, so I just decided to put a little extra work and thought into a system to refill the tank using other available water. We have the luxury of both Ag and PUD water on site. So, in summary, I am very pleased with the quality of the tank we purchased, and the price of the single, smaller tank certainly took some pressure off the project budget. It is a Norwesco poly tank (white) of 1750 USG capacity, suitable for potable water, that can be buried up to 30", IIRC. If I absolutely had to have a larger capacity, there are tank (systems) that are much more suited to connecting in series and I would look into them. Each tank in such a system is smaller, but that makes for easier handling and transport. Of course, more materials and labor in connecting the series...... |
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ICFHybrid
Veteran Member
Posts:2126
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| 30 Sep 2011 10:45 AM |
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Out here, (in WA State), as many western states, you don't own the rain that falls on your property. Just like you don't "own" the air.
http://www.ecy.wa.gov/programs/wr/hq/rwh.html |
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bpnkrtn
New Member
Posts:54
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| 30 Sep 2011 11:21 AM |
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Posted By ICFHybrid on 30 Sep 2011 10:04 AM
I am interested in the layer of "stuff". Earlier, you mentioned "first flow diverter". Did you have one and what was it like, i.e. how was it constructed and what portion of the flow did it divert before collection? Did you clean it religiously, just when it was full or what? Sounds like the layer of "stuff" was at the bottom, or was there a floating layer, too? Was the bottom layer fluffy and essentially suspended, or was it more silty and compact?
What kind of a roof did you collect from?
Roof was metal. The stuff was at the bottom of the tank. Some silt, dust, small particulate matter. I occasionally used a little 'chlorox' (few ounces in tank) to keep microbial growth controlled. The diverter was simplicity at work. I put a 'T' in the 4" PVC pipe going to the tank, facing down. Then ran pipe to the ground to an 'L' and then pipe along the ground for for 10 ft. ... because it came in a 10 ft. length. Then capped it. The first roof runoff would go into the diverter pipe and fill it up, then flow on into the tank ... assuming I had remembered to empty the diverter after the last rain. Various gizmos are available for sale now to accomplish this. I never calculated a diverted amount ... I always intended to do that and change/improve the system but time and money were short and it WAS working just fine. I never cleaned the diverter past opening it up after a rain and letting it empty/flush out. I did forget to replace the cap one time and lost a good rain's collection before I remembered it. The water stayed amazingly clear as long as I did not disturb the layer of stuff in the bottom and remembered the chlorox. I used the bottom outlet of the tank for the house supply line. It was just above where the sludge layer accumulated ... there are much better ways! I had a bank of three filters in the house, large whole house filters, a coarse one then a fine one and then an activated charcoal filter. I changed out the coarse filter cartridge about every 2 months based on need. In a few dry periods when we had to draw the tanks to a very low level I would have to change the filters more often. Once, I let one tank almost empty then when the next rain hit it was an intense thunderstorm that dumped a lot of water, very fast, into the tank and really stirred up the sludge. For the next month I had to change the coarse filter weekly ... my fault, not the systems. Holler if you have other questions. A last note: When your water is from rain and your power is from the sun, you come to really dislike cloudy, overcast days (if it doesn't rain.) |
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Alton
Veteran Member
Posts:1758
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| 30 Sep 2011 12:35 PM |
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I may have missed this in an earlier posting, but did you filter the rain water before it entered the collection tank? |
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| Residential Designer &
Construction Technology Consultant -- E-mail: Alton at Auburn dot Edu, 334 826-3979 |
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bpnkrtn
New Member
Posts:54
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| 30 Sep 2011 01:26 PM |
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Posted By Alton on 30 Sep 2011 12:35 PM
I may have missed this in an earlier posting, but did you filter the rain water before it entered the collection tank?
Not unless you count the gutter screens :) |
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ICFHybrid
Veteran Member
Posts:2126
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| 01 Oct 2011 11:35 PM |
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I never calculated a diverted amount That's 12 or 13 gallons in the diverter you described. That's right down at the bottom end of what is recommended for 1700 ft2 of roof. If you kept cleaning it out, you must have felt your diverter was doing a job for you. I assume you found a lot of stuff in it each time. What did your water taste like, (particularly if you didn't get to the activated charcoal filter regularly)? Did you have any plastic or metal tastes? Did it ever taste like Clorox? Were your tanks black poly? I will collect from three downspouts with a diverter at each one. Each one covers between 1500 -2800 sf of roof area. Then, they pipe together before running into the cistern. I decided not to put a single coarse filter inline before it goes into the cistern. I'd like to get as much pre-filtration as possible, but I don't want to be tied to cleaning out a filter all the time and I certainly don't want it to clog up creating a backup. I'm going to try to let the diverters do the job. I just installed the inlet today with a calming fitting. The standpipe goes all the way to the bottom of the tank with the fitting on the bottom and allows the incoming water to well up without disturbing the bottom layer. We will see how that works over time. |
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ICFHybrid
Veteran Member
Posts:2126
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| 01 Oct 2011 11:44 PM |
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Ive built two simple ones for about 500$ including my time for labor. Sounds like your diverter was the only filtration on your systems. Did you ever get a chance to look at what kind of sediment the tanks had accumulated? |
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bpnkrtn
New Member
Posts:54
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| 02 Oct 2011 10:27 AM |
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Posted By ICFHybrid on 01 Oct 2011 11:35 PM
I never calculated a diverted amount That's 12 or 13 gallons in the diverter you described. That's right down at the bottom end of what is recommended for 1700 ft2 of roof. If you kept cleaning it out, you must have felt your diverter was doing a job for you. I assume you found a lot of stuff in it each time.
What did your water taste like, (particularly if you didn't get to the activated charcoal filter regularly)? Did you have any plastic or metal tastes? Did it ever taste like Clorox? Were your tanks black poly?
I will collect from three downspouts with a diverter at each one. Each one covers between 1500 -2800 sf of roof area. Then, they pipe together before running into the cistern. I decided not to put a single coarse filter inline before it goes into the cistern. I'd like to get as much pre-filtration as possible, but I don't want to be tied to cleaning out a filter all the time and I certainly don't want it to clog up creating a backup. I'm going to try to let the diverters do the job.
I just installed the inlet today with a calming fitting. The standpipe goes all the way to the bottom of the tank with the fitting on the bottom and allows the incoming water to well up without disturbing the bottom layer. We will see how that works over time.
When I said I cleaned it out I just meant that I unscrewed the cap/plug and let it flush out or drain, then replaced the plug. Nothing more. The amount of debris in the diverter varied greatly from event to event depending on how long since the last rain, the amount of blown dust, season, etc. The house was in the middle of a hardwood forest It always amazed me at just how much dust was blowing around in a forest with near 100% ground cover.
The water had a near 'distilled water' taste, or lack of taste. I took water in to work occasionally and conducted noon time taste panels comparing it to distilled water and tap water there at the University. No one ever noted an off taste or odor. A couple of times I caught rain in a pitcher so I could compare it to the 'stored' water ... I never thought there was any difference in taste or odor. That was with the activated charcoal filter changed at 6 month intervals. The clorox taste/odor was the most noticeable if I let the charcoal filter go too long and basically became my trigger to change the filter. Strangely enough, I would get the 'clorox' odor in a hot shower before I would detect a taste in the drinking water.
The lower tanks were white poly and the upper tank was a dark green. The white tanks were the typical inexpensive "Tractor Supply" water tanks. The upper green tank was a home water supply tank made up in North Carolina (It cost more than the 2 lower tanks combined.)
If you have 4500+ sf of collection surface you are sure going to overflow/back-up one supply line in an intense rain event, unless it's really large diameter! The germans make an in-line filter that is self cleaning and it comes in different capacities (sizes). I'll try to find a link to information.
You did the inlet right. Initially I just had an inlet pipe go about 4 inches into the top of the tank ... not the way to do it, although I lived with that for several years.
If I may ask, where are you located and what is the average annual precip? |
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ICFHybrid
Veteran Member
Posts:2126
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| 02 Oct 2011 01:11 PM |
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you are sure going to overflow/back-up one supply line in an intense rain event, unless it's really large diameter! They are 4" pipes. I hoped each of the three would be fine on it's own, but where they come together; that one is going to be roaring. Hope the single 4" overflow outlet can handle it......... I put a skimmer on it so it continually cleans itself of floating debris, anyway. These last few years we seem to be getting more and heavier events, but they still don't last too long compared to other places. More often, it's light rain for days.... I'm in Western Washington. We used to get 30"-32" a year, but it has been wetter as of late..... I'm really trying to keep the maintenance items - filters and whatnot - more accessible (up by the downspouts) so I am encouraged to take care of them as opposed to having to open the riser and hang two feet below ground. Unfortunately, that means three of everything instead of just one..... Thank you for the water quality info. Really appreciate it. |
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rainwatergeek
New Member
Posts:1
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| 07 Oct 2011 03:39 PM |
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You can see a video of a house in Houston that uses rain for all the water in the home at: http://www.sparkletap-rain.com
There is an e-book available on the website that helps DIYs build a system from start to finish.
It is also available for the Kindle at: http://www.amazon.com/dp/B005HJRBWE
New laws are being passed in Colorado that allows homeowners to collect rain for use on their own property. California has a bill on the governor's deck right now to allow it there. Only Utah and Washington still have laws prohibiting it. It is the best bathing and clothes washing water because it is soft. Plants love it because it isn't chlorinated. I have a system on my home near Galveston and after Ike, I had the only water on the island to clean up with since the city had shut off the water. I love it.
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ICFHybrid
Veteran Member
Posts:2126
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| 07 Oct 2011 11:03 PM |
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Only Utah and Washington still have laws prohibiting it. Previously, it wasn't prohibited in WA as much as it wasn't specifically allowed. In any case, all that has changed as of a couple of years ago. You are now expressly allowed to collect rooftop water in WA. |
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