[Water] Rainwater / Rainfall Collection (merged)

[lowem]

I would've liked to see some snow over here. Instead it's been getting warmer and very dry.

Usually the RH is 80-90% for our "hot and humid" tropical climate, lately it's been hitting 60-70% only - which is kind of odd.

Let's see what the weather has got to show us next.

[BabyPeanut]

People seeing an increase.....maybe there is a lot of flooding..but is it like this.....dry,dry,dry,dry,dry, and then finally......FLOOD!!!! That seems to be whats happening...either drought..or drought then flood..nothing normal.

Not really; I'm in the Great Lakes region, and this past spring it was just rain, rain, rain.

Same in the mid-atlantic region.

Beside doesn't the song go "it never rains in California...it pours"?

[Cyrus]

Well chargrove's regional theory sounds most true....although i am in the great lakes region and am seeing a definite decrease...weird.

[PeakOiler]

I thought I would relate some information regarding rainwater collection for homeowners from my own experiences.

Assuming one doesn't have neighborhood residential restrictions for setting up some cisterns to collect rainwater off one's roof, then consider the following:
Each 1,550 gallon high-density polyethylene (HDPE) tank cost me about $439 from a "local" vendor--about 60 miles away. I bought three tanks. (I'm about to invest in three more 1,550 gallon tanks this year.) Shipping costs was about $120. The PVC pipes and fittings were about $200. The ballast pump was about $700. The $60 filter assembly included a 5 micron sediment filter and a 3 micron carbon filter and two pressure guages. The ultraviolet lamp (see http://www.ultraviolet.com )was about $700. Rain gutters should be considered part of the cost of a rainwater collection system, but rain gutters aren't always used for collecting rainwater, since people put them on houses anyway for some reason.
I spent about $450 for rain gutters so I will include that cost here in this analysis.
Total investment: Approximately $3550. I spread this out over two years.

One cannot plumb a rainwater (nor a wellwater system for that matter) to any city service public water line-- "T'd" to the house-- unless you get a special permit (more $$$) which requires additional equipment such as back flow preventors, and the additional equipment must be installed by a certified plumber (more $$$) and inspected annually (more $$$). Of course, one may not want to pay such permitting fees and annual inspection fees every year. Forget that. A stand-alone rainwater system is less expensive than to pay for annual permits and inspections.

Additional ongoing maintenance costs include new filters after about two months or after filtering about 5,000 gallons of water. Home Depot sells the twin filter pack for $45. The frequency of replacing filters can vary, depending on how clean your rainwater is coming off the roof and how much water one uses. Leaves from roof-overhanging trees are not good for rainwater collection systems. Screens in the gutter downspouts work pretty well for large debris, and there are a couple of other plumbing tricks that remove solids that I won't detail here, but will prolong the life of the micron filters.

As far as rainwater saving energy, this could be debated. I now use more electricity per month at my house for the UV lamp and the pump. The UV lamp I have draws 36 watts, 24/7. The pump comes on everytime you turn on the water. I estimate the rainwater system uses about 30 additional kilowatt-hrs per month, about $3/mo. at my electric rate. I wonder how much power (or other embedded costs) I save the city water company. ???

Since I don't have enough storage capacity yet to last me through the dry summer season, I still am paying the city water company their $25 /mo. minimum fee to maintain their service if needed. Once I get more capacity, I can quit the city water service and then the payback begins...

The benefits:

The rain here in Central Texas is only slightly acidic, about pH 6.8. There is no limestone (calcium carbonate) in the rainwater compared to the city water. The city water ruined both toilets after 30 years from lime buildup. The new toilets should last forever with soft rainwater. Likewise for shower heads, faucets, hot water heaters, etc.

The dishes come out spotless.

The rainwater does not leave lime in my solar water still.

Clothes are cleaner.

There's no arsenic or lead in rainwater.

See http://www.rainwatercollection.com for more information.

James

The edit corrected the price per 1,550 gallon tank (at that time of purchase) and the total estimate.

[pup55]

You and kpeavy are my two heroes.

How expensive is water in Central Texas?
Does the city still charge you for sewer?
What's your typical monthly water consumption?

[PeakOiler]

<<You and kpeavy are my two heroes.


How expensive is water in Central Texas?
Does the city still charge you for sewer?
What's your typical monthly water consumption?>>

Thanks for your reply.

How expensive is water in Texas? Well, that depends on if you buy all your drinking water at the local grocery in those designer plastic bottles, doesn't it?
':-D'

My typical household water consumption is less than 2000 gal/month.

Watering my small orchard and garden from rainwater requires about another 1000-2000 gal/mo during the growing season, (and that keeps expanding,) but doesn't require any additional electricity, since that irrigation is all gravity flow. I hope they don't start charging me for using gravity.
I still need to learn more about water requirements for specific trees and plants, and water conservation in other respects, to maintain a growing environment in this agricultural community that I live in.

Since I have a house in the country, but still connected to the local city water system, (for a little while longer), the house uses a septic tank. No sewer service other than to pay the septic service about $120 every 3 years.
Interesting that the drain field of the septic system is always green even in the summer months.

[Frank]

thanks for the link

[gg3]

Very useful info.

How many people in your household?

Something else to consider: Graywater recycling. Store the used water from the washing machine in an attic tank that feeds down to the toilet tanks. This will get you the equivalent of "free" toilet flushes. I'm building a system presently (more details later in a separate topic).

How far are you from the nearest main roads? Reason I ask, I'm in a city a few blocks from main roads, and judging from the amount of black soot that routinely collects on the window ledges, there's no way the rainwater here is drinkable (i.e. the soot is only the most visible component of localized air pollution that probably contains other nasties).

[Frank]

I'm planning a cistern-like system now to use rainwater to flush toilets, wash clothes, etc. It'll use a 24 VDC pump that draws less energy than my deep well pump and is nicer to our PV system.

[PeakOiler]

<<How many people in your household?>>
Just me.

<<Something else to consider: Graywater recycling. Store the used water from the washing machine in an attic tank that feeds down to the toilet tanks. This will get you the equivalent of "free" toilet flushes. I'm building a system presently (more details later in a separate topic).>>

Wouldn't installing an attic tank require another pump to raise the graywater to a greater height? If the electricity goes down, I can always just use gravity flow to fill buckets and manually pour the water into the toilet tanks, the sink, bathtub, or the washing machine. Without electricity, however, I wouldn't be able to pump the water up to the solar water heater on the roof.

<<How far are you from the nearest main roads? Reason I ask, I'm in a city a few blocks from main roads, and judging from the amount of black soot that routinely collects on the window ledges, there's no way the rainwater here is drinkable (i.e. the soot is only the most visible component of localized air pollution that probably contains other nasties).>>

My house is 1/3 mile from the nearest road. Yes, collecting rainwater in an urban environment would probably require a water softener and reverse osmosis (RO) in addition to pre-filtration and UV purification. The problem with softeners and RO is that they need a lot of salt. A water softener/RO system wastes 2/3 of the water. One would not want to use salt water as graywater for gardens or trees.

Even though I have the rainwater system plumbed to the house, I use a solar still for drinking and cooking water. See www.solaqua.com for solar water stills. Yesterday was a blue sky day and it distilled about 4 liters of water. In the summer, the still will produce about 6 liters/day.

Now this is amusing: I haven't used any city water since the week before Christmas and my last water bill from the city said I used 0 gallons. (The bill before that said I used about 200 gallons, but I think that was due to "rounding".) I noticed they replaced the meter last week. Apparently they thought the meter had broken!

[PeakOiler]

<<I'm planning a cistern-like system now to use rainwater to flush toilets, wash clothes, etc. It'll use a 24 VDC pump that draws less energy than my deep well pump and is nicer to our PV system.>>

I considered using solar PV for the UV lamp and the ballast pump.
According to my calculations, a 36 watt UV lamp operating 24/7 would require the following if I got 5.5 hrs of sun/day:
Three 100 watt panels @ $450/panel.
Six 100 amp-hr batteries @ $250/battery (12 V).
Inverter: $250
Charge controller: $75
Wire, hardware: $30
Total: $3205
And that's just for the UV lamp and not the ballast pump.

[PeakOiler]

<< Each 1,550 gallon high-density polyethylene (HDPE) tank cost me about $239 from a "local" vendor--about 60 miles away.>>

Correction: Each 1,550 gallon tank cost $439.
My apologies, I did not mean to mislead anyone. Add another $600 to the cost estimate in the original post.

[PeakOiler]

[How expensive is water in Central Texas?]

My city utility water rate is about $0.01 per gallon, but as I pointed out, it is very hard water. Remember that an advantage of rainwater is that it has never touched the ground. So immediately, one has purer water assuming good air quality.

Basically, my home rainwater system is a water softener without buying the salt and putting salt into the water table.

If you want to know what is in your rainwater, collect some samples and take them to a water testing lab. Water tests are not that expensive. (But that depends on what analytes and/or on how many analytes one tests for.)
The best tests for rainwater are total dissolved solids, (TDS), turbidity, and/or total organic carbon, (TOC).

[Frank]

<< Each 1,550 gallon high-density polyethylene (HDPE) tank cost me about $239 from a "local" vendor--about 60 miles away.>>

Correction: Each 1,550 gallon tank cost $439.
My apologies, I did not mean to mislead anyone. Add another $600 to the cost estimate in the original post.

Can you post a link to your tank supplier? Seems like a good price.

[OldSprocket]

I considered using solar PV for the UV lamp and the ballast pump.
According to my calculations, a 36 watt UV lamp operating 24/7 would require the following if I got 5.5 hrs of sun/day:
Three 100 watt panels @ $450/panel.
Six 100 amp-hr batteries @ $250/battery (12 V).
Inverter: $250
Charge controller: $75
Wire, hardware: $30
Total: $3205
And that's just for the UV lamp and not the ballast pump.

This is exactly why my UV lamp is on only when I run water (plus a little extra time before and after to make sure no little beasties sneak through). It means that I use a 6-gallon reservoir inside to hold treated water. All the water here is rooftop water collected in a cistern.

It's not the most convenient system (understatement alert), but it works with my very small solar-electric system. I plan to re-design the system for the future house here. I don't plan to run a UV tube 24/7.

Ultraviolet LEDs are now down to 350 nm wavelength, but they need to emit 250 to 265 nm to effectively disinfect anything. You can believe I'm keeping track.

[Papey]

Why don't you use solar distillation instead of UV purification ? It seems to me it would be more sustainable in the long term.

[OldSprocket]

Why don't you use solar distillation instead of UV purification ? It seems to me it would be more sustainable in the long term.

Do you know of a solar still that runs continuously? Most solar distillation systems are "batch" systems and are fairly large for the amount of water produced. Solar variation leaves questions about how well water has been disinfected. Batch systems often have a melting-wax indicator.

UV is continuous and will purify water all day and night. The electricity is worthwhile if it is doing work; it's wasted if no water is running. The amount of radiation is nearly constant allowing a known flow-rate to reliably disinfect water.

Neither solar nor UV has any "residual" action. I don't want to store a lot of "clean" water in hopes that it remains clean.

Right now I'm concentrating on building a house. Some of the finer points of sustainability fall lower on my to-do list.

[PeakOiler]

[<<Can you post a link to your tank supplier? Seems like a good price.>>]

Sorry, they don't have a website, but the company is
290 Fence & Ranch Supply Co.
Hwy 290 West
P.O. Box 241
Dripping Springs, TX 78620
512-858-7876

The approx $430 per 1550 gal tank was the price in May, 2003.

[gg3]

Tanks:

http://tank-depot.com/


Pumps:

http://www.go2marine.com/frameset.jsp?servletPath= (line break added here, paste these together)
/g2m&action=ViewSimilarItems&id=86244F&preview=false

(or www.go2marine.com and put "bilge pumps" into their search box)


Peakoiler:

Attic tank graywater design does require pumps. The system I'm building is the "apartment version" where the tanks are on the main floor and visible. That still requires pumps. In any case, a hand pump such as a diaphram-type bilge pump, will get the water up to the attic nicely.

For your washing machine's graywater output: have a surge tub or tank into which the washer can discharge water normally. Then pump the water from that tank up to the attic tank or whatever.

It appears that the diaphram pumps are the best hand-powered pumps in terms of gallons per minute. However they would have to be permanently mounted to a surface, e.g. a wall (into the studs with heavy screws).

Note also, you need a separate pump for each grade of water you're handling. Can't count on sterilizing one pump while switching it back and forth between uses (e.g. clean water to tank A, graywater to tank B, etc.).


---

The big water-consumer for laundry is rinsing. Getting all the detergent out. The key to reducing rinse water consumption is to be able to judge the minimum amount of detergent you need to get a load clean. A good long soak will help, and will also reduce the amount of time you need to run the agitator (additional incremental energy savings).

---

Cisterns are iffy at best in Northern California; we get all of our precipitation in the winter, so we'd have to store a year's worth of water, which could be impractical (or I might be wrong; I should sit down and do the arithmetic). However the public water supplies here are pretty sound and I don't expect serious trouble in that department (or, if there is, it's time to evacuate before the epidemics set in...)

---

UV LEDs: Very interesting; keep us posted!

---

[Frank]

thanks for the info