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12-16-2018, 07:18 AM
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#1
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1 Rivet Member
2004 22' International CCD
Patuxent River
, Maryland
Join Date: Jan 2018
Posts: 17
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Grey water recycling idea
Hi all. Just moved into my 22’ International CCD and am slowly getting settled. My setup is 100% off grid – no hookups. I am located in MD, so it’s cold this time of year, but I have the propane heater working just fine. I am in the process of putting together a 400W solar system for electricity. Currently using a cheap generator until it’s complete. That leaves me with my water “problem”, and the reason for reaching out on the forums today.
I am located near a natural water source. Initial plan was to pull water from the source into the trailer with a 12v pump, after filtration via micron and carbon filters. Issue I ran into is the water source is brackish. I am estimating 5,000-10,000ppm, and would therefore require some sort of desalination process to make it potable. I built the pump and filtration system anyway, and it fits nicely into a pelican case. It is powered via an onboard (in the case) 20W panel and a 4Ah battery and is completely self-contained. After speaking with my friend about my dilemma, he recommended I explore the idea of using that system to purify grey water for re-use. I’m reaching out to the forums to get more ideas on this process, specifically related to the plumbing technicalities as well as the overall feasibility of purifying grey water.
I’d like you to poke holes in this plan. Grey and fresh water tanks would be full (21gal and 30gal, res.). My filtration system would be plumbed into bottom of grey tank and would feed city water connection (pump will maintain 20-60psi output, depending on setting). Fresh water tank would be used for refilling grey tank when it gets low. Every few weeks I would top off the fresh water tank with 5 gallons or so – essentially whatever amount is consumed for drinking, cooking, and other minor losses. This, in theory, would permit “unlimited” length showers, which would be a nice side-affect.
Open to suggestions. Cheers!
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12-16-2018, 08:20 AM
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#2
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3 Rivet Member
2019 22' Sport
Currently Looking...
Cohasset
, Massachusetts
Join Date: Dec 2016
Posts: 136
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Maybe reach out to NASA. On the space station I believe they recycle and use ‘all’ the water. I mean ALL the water. They could probably tell you what kind of technology and filtration that takes.
Rich
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12-16-2018, 08:56 AM
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#3
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Half a Rivet Short
2017 30' Classic
2022 Interstate 24X
Carlisle
, Pennsylvania
Join Date: May 2017
Posts: 15,674
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Hi
Any *safe* form of water re-use is going to be a very complex process. Rendering "natural" water safe is also a bit complex. There are a lot of things that can get into water. Often "canned" solutions cover the bases better than DIY setups. The yacht world run gear to go from saltwater to fresh water. Generally a gallon a day is a pretty good number. They *do* gobble up power doing it.
NASA plays games with distillation. They have a *lot* of solar to work with so that is a bit of an advantage.
Bob
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12-16-2018, 09:43 AM
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#4
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1 Rivet Member
2004 22' International CCD
Patuxent River
, Maryland
Join Date: Jan 2018
Posts: 17
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Thanks for the comments, gents. The gentleman that offered up the recycling idea happens to work at NASA and is quite familiar with the inner-workings of the ISS. He says they re-use a high percentage of the grey water, but still need to resupply occasionally due to unavoidable losses. I suppose my approach at this point will be to get a water sampling kit and run some tests on the recycled water to evaluate its quality.
I'm thinking of tapping into the low-point drain on the grey tank. I'm not currently at my Airstream at the moment. Does this drain have a fitting of sorts on it that, say, a garden hose could attach to?
Edit: I should add that I have toyed with the idea of reverse osmosis filtration as a means to access the local water source but as was mentioned previously, the electrical demand would be enormous - much too high for my simple battery bank.
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12-17-2018, 07:46 AM
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#5
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Half a Rivet Short
2017 30' Classic
2022 Interstate 24X
Carlisle
, Pennsylvania
Join Date: May 2017
Posts: 15,674
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Quote:
Originally Posted by Dashash
Thanks for the comments, gents. The gentleman that offered up the recycling idea happens to work at NASA and is quite familiar with the inner-workings of the ISS. He says they re-use a high percentage of the grey water, but still need to resupply occasionally due to unavoidable losses. I suppose my approach at this point will be to get a water sampling kit and run some tests on the recycled water to evaluate its quality.
I'm thinking of tapping into the low-point drain on the grey tank. I'm not currently at my Airstream at the moment. Does this drain have a fitting of sorts on it that, say, a garden hose could attach to?
Edit: I should add that I have toyed with the idea of reverse osmosis filtration as a means to access the local water source but as was mentioned previously, the electrical demand would be enormous - much too high for my simple battery bank.
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Hi
RO really does *not* have a high electrical demand. A normal filter based setup will get you a gallon a day and dump about 5 gallons a day. Your pump will need to "move" 6 gallons as a result. No more power than running the pump in your trailer to move the same amount of water. I've run RO setups like that for years and years.
RO does *not* get rid of all the "bad stuff" in a water supply. The testing required to be sure that a system is safe is pretty involved. It is not uncommon to find that your local water authority has a hard time keeping up with all of it.
This all assumes you will be drinking the water / using it for cooking / washing the dishes with it. If the water source is simply for the shower and the bathroom ... that's a totally different objective.
Bob
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12-17-2018, 09:01 AM
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#6
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Rivet Master
Churubusco
, Indiana
Join Date: Nov 2017
Posts: 2,007
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I happen to be an engineer that makes satellites for NASA, i don't have anything to do with the space station or water filtration though.
You're not in space though, copying the space station setup is probably extreme overkill.
Something that comes to mind is all the crud that develops in the grey tank. Beard trimmings, toothpaste, food bits, etc. I'd put the fitting an inch or so off the bottom.
If you're fully stationary, I'd think an external system would be easier than trying to fit it all internal to the Airstream.
Bury two containers (so they don't freeze, could also just heat them) and do a natural purification setup. Gravel/sand/charcoal/etc. in the first container, store this clean water in the second container. This minimizes rework to your existing plumbing, lets you "flush" the grey tank into it every now and then, and you can also collect rainwater into it, pump your brackish water source into it, etc.
Once you've got it filtered to your hearts content, I'd use a UV sanitizer for the water that gets used for drinking/cooking to take care of the last of the viruses.
There is a lot of information online about how to safely filter water, more than I know off the top of my head
Why the constraint of trying to fit it in a pellican case?
__________________
1983 Airstream 310 Class A Motorhome
-Rob
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12-17-2018, 11:36 AM
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#7
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3 Rivet Member
1971 27' Overlander
Kansas City
, Kansas
Join Date: Jul 2018
Posts: 235
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Quote:
Originally Posted by uncle_bob
Hi
Any *safe* form of water re-use is going to be a very complex process. Rendering "natural" water safe is also a bit complex. There are a lot of things that can get into water. Often "canned" solutions cover the bases better than DIY setups. The yacht world run gear to go from saltwater to fresh water. Generally a gallon a day is a pretty good number. They *do* gobble up power doing it.
NASA plays games with distillation. They have a *lot* of solar to work with so that is a bit of an advantage.
Bob
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A gallon a day for salt water filteration? The one I used gave 5 gallons an hour. It's normal to see systems that give 30gph.
Rendering natural water safe. It's actually pretty easy if you do your research. As always. Boiling it is the easiest method to come to mind. Many filters remove viruses. Uv, another great method. You see in many developing countries, piles of plastic pet bottles all over everyone's roof. This is the most simple form of UV purification that millions of people without access to clean water do on a daily basis.
Your experimentation and imagination are your limits!!
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12-17-2018, 09:04 PM
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#8
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1 Rivet Member
2004 22' International CCD
Patuxent River
, Maryland
Join Date: Jan 2018
Posts: 17
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Loving the conversation.
The pelican case came about as a design feature for my original project, which was to create a self-powered, contained, and portable water filtration system for car campers, overlanders, hunting/fishing cabins, etc. The idea was that you simply deploy the unit wherever you need fresh water and everything required for the operation is contained within the sturdy shell of the pelican. This idea, naturally expanded (as most of my ideas tend to), into creating a filtration system for my semi-permanently anchored Airstream that takes advantage of nearby water.
Regarding RO - my brief research has led me to the conclusion that pump output pressure required through the RO membrane is relative to the salinity of the water. Ocean water is around 35,000ppm, fresh water is <500ppm, and the water I have access to is 5,000-10,000ppm (based on salinity charts - haven't tested it myself). Ocean water requires ~800psi, brackish (~10,000ppm) requires ~200psi, and lightly brackish (<1,000ppm) requires even less psi. A pump that can deliver 200psi is going to be upwards of 10amp draw, which would be stretching my current setup.
I really do like the idea of the natural filtration with charcoal, sand, etc. This wouldn't remove salt, though, correct? I need to do more research in that area.
I think there's a middle ground here where I use brackish water from the local source for showering and flushing (maybe just carbon and micron filters), and haul in clean water for drinking, cooking, dishes, etc. Either way I'll keep everyone up to date with the progress. In the meantime, here are some pictures of the filtration design.
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12-17-2018, 09:07 PM
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#9
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1 Rivet Member
2004 22' International CCD
Patuxent River
, Maryland
Join Date: Jan 2018
Posts: 17
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Pictures:
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12-17-2018, 09:07 PM
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#10
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Rivet Master
2017 23' Flying Cloud
Parker
, Colorado
Join Date: Oct 2016
Posts: 1,772
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I do water for a living. To get water to potable can be done, you need physical filtration and then some form of disinfection (UV, OZONE, Chlorine) to be safe. I’m not sure you could miniaturize a system required to treat to potable standards that requires little energy use.
Don’t forget the disinfection step.....
__________________
Thanks,
Troutboy
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12-18-2018, 04:40 AM
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#11
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1 Rivet Member
2004 22' International CCD
Patuxent River
, Maryland
Join Date: Jan 2018
Posts: 17
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Quote:
Originally Posted by Troutboy
I do water for a living. To get water to potable can be done, you need physical filtration and then some form of disinfection (UV, OZONE, Chlorine) to be safe. I’m not sure you could miniaturize a system required to treat to potable standards that requires little energy use.
Don’t forget the disinfection step.....
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Understood. I've always wondered how long (generally) water should be exposed to UV light to be "completely" disinfected. Do you have any information on UV light sizing requirements for a given volume of water? Could I, say, place a UV light on top of a 1/2" diameter section of plastic piping (flowing water) and disinfect flowing water as it is pumped?
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12-18-2018, 05:12 AM
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#12
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Rivet Master
2014 20' Flying Cloud
Sag Harbor
, New York
Join Date: Jun 2015
Posts: 17,523
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”Feel free to poke holes . . . ?”
Way overthinking this.
Labor costs far exceed rewards.
One deep freeze plus possible fuel re-supply issues, notably a week without sun, would torpedo the entire rig.
Sheer folly IMO.
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12-18-2018, 06:25 AM
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#13
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Rivet Master
1991 25' Excella
2011 19' Flying Cloud
Santa Ynez
, California
Join Date: Jan 2017
Posts: 1,185
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From a code, safety and health standpoint any connection between the grey or waste water and the fresh tank would be a serious no no.
__________________
Good judgment comes from experience, and a lot of that comes from bad judgment.
Will Rogers
Alan
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12-18-2018, 08:21 AM
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#14
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Rivet Master
2000 25' Safari
Davidson County
, NC Highlands County, FL
Join Date: Aug 2006
Posts: 4,493
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Quote:
Originally Posted by Dashash
<<snip>>
I think there's a middle ground here where I use brackish water from the local source for showering and flushing (maybe just carbon and micron filters), and haul in clean water for drinking, cooking, dishes, etc. Either way I'll keep everyone up to date with the progress. In the meantime, here are some pictures of the filtration design.
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I think you are onto the solution! I would add a touch of chlorine to the water tank each time it is filled.
This should work, if your solar/pump/filter system can produce enough water to meet your toiletry needs.
Each time if/when you move the trailer to somewhere you have hookups, do a complete sanitizing of the water system to enjoy full use.
When you sell the trailer make sure this "unusual use" is fully disclosed to the new owner.
ps: to make the pump work on your schedule (day or night), you might consider solar charging a battery to power the pump. Or, power the pump from the trailer's batteries.
ps2: Did you consider digging a shallow well or driving a well point? This will lessen the likelihood of getting critters in the FW tank. How are you disposing of sewerage (thinking of well contamination)?
__________________
Alan
2014 Silverado LTZ 1500 Crew Cab 5.3L maximum trailering package
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12-18-2018, 11:03 AM
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#15
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Half a Rivet Short
2017 30' Classic
2022 Interstate 24X
Carlisle
, Pennsylvania
Join Date: May 2017
Posts: 15,674
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Quote:
Originally Posted by Shermy1987
A gallon a day for salt water filteration? The one I used gave 5 gallons an hour. It's normal to see systems that give 30gph.
Rendering natural water safe. It's actually pretty easy if you do your research. As always. Boiling it is the easiest method to come to mind. Many filters remove viruses. Uv, another great method. You see in many developing countries, piles of plastic pet bottles all over everyone's roof. This is the most simple form of UV purification that millions of people without access to clean water do on a daily basis.
Your experimentation and imagination are your limits!!
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Hi
Do you *need* 5 gallons an hour on something that can run 24 hours a day? System size *does* scale with how much the setup puts out. If you need 5 gallons out continuously then yes, you will be pumping 25 or so gallons an hour 24 hours a day. You will use some power pumping 600 gallons of water to get your 120 gallons you (apparently) use each day.
As soon as you dig into all of the weird chemicals that *might* be in a water source, getting rid of them is not all that easy. In this day and age of long forgotten industrial sites (especially on the east coast) that is *not* an idle speculation. In this respect, mid ocean sea water is a better source than a local stream.
Bob
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12-18-2018, 02:30 PM
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#16
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1 Rivet Member
2004 22' International CCD
Patuxent River
, Maryland
Join Date: Jan 2018
Posts: 17
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Quote:
Originally Posted by OTRA15
”Feel free to poke holes . . . ?”
Way overthinking this.
Labor costs far exceed rewards.
One deep freeze plus possible fuel re-supply issues, notably a week without sun, would torpedo the entire rig.
Sheer folly IMO.
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I really can't argue with you regarding your over-thinking point. The simplest solution, if "labor costs" were a concern, would be to haul in fresh water or drive the trailer to a spigot each week for resupply. I don't consider this project "labor", but instead, consider it more of a science project. I've learned an incredible amount about the water purification process as a result of the project, and that's really the point. I'm fortunate enough to have the time and resources to experiment with this stuff, despite humans having figured this out, mostly, WELL before me!
Regarding your point about the no-sun-torpedo attack on the rig - that's not a concern. If that happened, I would just tow the trailer to the spigot and fill with city water . No, but honestly, I would charge the tiny battery with my trailer batteries, generator, or tow vehicle (as a last resort). If there was a deep freeze, I would conserve the water I had stored.
And back to my original post, the portable solar-powered filtration system was intended for use in my 4x4 on camping trips. I'm simply trying to adapt it for use in my airstream - again, just for fun.
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12-18-2018, 02:32 PM
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#17
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1 Rivet Member
2004 22' International CCD
Patuxent River
, Maryland
Join Date: Jan 2018
Posts: 17
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Quote:
Originally Posted by uncle_bob
Hi
Do you *need* 5 gallons an hour on something that can run 24 hours a day? System size *does* scale with how much the setup puts out. If you need 5 gallons out continuously then yes, you will be pumping 25 or so gallons an hour 24 hours a day. You will use some power pumping 600 gallons of water to get your 120 gallons you (apparently) use each day.
As soon as you dig into all of the weird chemicals that *might* be in a water source, getting rid of them is not all that easy. In this day and age of long forgotten industrial sites (especially on the east coast) that is *not* an idle speculation. In this respect, mid ocean sea water is a better source than a local stream.
Bob
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Great point. I have every intention of testing my natural water source prior to use.
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12-18-2018, 02:38 PM
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#18
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1 Rivet Member
2004 22' International CCD
Patuxent River
, Maryland
Join Date: Jan 2018
Posts: 17
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Quote:
Originally Posted by A W Warn
I think you are onto the solution! I would add a touch of chlorine to the water tank each time it is filled.
This should work, if your solar/pump/filter system can produce enough water to meet your toiletry needs.
Each time if/when you move the trailer to somewhere you have hookups, do a complete sanitizing of the water system to enjoy full use.
When you sell the trailer make sure this "unusual use" is fully disclosed to the new owner.
ps: to make the pump work on your schedule (day or night), you might consider solar charging a battery to power the pump. Or, power the pump from the trailer's batteries.
ps2: Did you consider digging a shallow well or driving a well point? This will lessen the likelihood of getting critters in the FW tank. How are you disposing of sewerage (thinking of well contamination)?
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Excellent points. Thank you.
As it is now, the pump is powered via a small battery which is topped off with a small solar panel. Daily operation will be limited to only 40 minutes with a full battery, and 60 minutes with a constant charge from the panel. It is a 33% duty cycle pump and not intended for continuous use.
I cannot dig a well at my location unfortunately.
For sewage, I must haul this out via tote to the local dump RV dump site like everyone else. I try to limit my "business" to the gym at work as much as possible .
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12-18-2018, 03:09 PM
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#19
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Rivet Master
2014 20' Flying Cloud
Sag Harbor
, New York
Join Date: Jun 2015
Posts: 17,523
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Quote:
Originally Posted by Dashash
. . .
If that happened, I would just tow the trailer to the spigot and fill with city water . No, but honestly, I would charge the tiny battery with my trailer batteries, generator, or tow vehicle (as a last resort). If there was a deep freeze, I would conserve the water I had stored.
. . .
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All in the middle of a blizzard with the temp below zero Fahrenheit?
How much propane will you burn to keep the stored water liquid?
There are plenty of posts here about other dreamers who tried to make it through Colorado winters full time. No fun and very expensive!
Good luck,
Peter
PS will search for CO posts later. Very eye opening!
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12-18-2018, 03:19 PM
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#20
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1 Rivet Member
2004 22' International CCD
Patuxent River
, Maryland
Join Date: Jan 2018
Posts: 17
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Quote:
Originally Posted by OTRA15
All in the middle of a blizzard with the temp below zero Fahrenheit?
How much propane will you burn to keep the stored water liquid?
There are plenty of posts here about other dreamers who tried to make it through Colorado winters full time. No fun and very expensive!
Good luck,
Peter
PS will search for CO posts later. Very eye opening!
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Propane usage: ~40lbs/week in dead of winter (living space heater only). Tanks heated electrically (12V). Thankfully, MD does not regularly see single digit (F) temperatures, let alone sub-zero. I will survive the winter, but thanks for your concern!
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