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Davpmars
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# Posted: 4 Jul 2023 18:30
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My Buddy is building a little cabin in northern Utah. We are at a point to consider what to do about a water supply. Digging a well is extremely expensive. We are looking at an underground water tank that we can have filled in the fall time to last through the winter.
The purpose of this post is to get ideas on how to protect it from freezing. From what I have read, we need to bury the tank, a minimum of 8 feet deep to get below the frost line. However, the ground is very rocky so that may not be a possibility. We definitely want to bury the tank but if we cannot get it below the frost line, how would you go about keeping it from freezing through the winter? What would you do?
We do have electricity at the property. We want to have the property usable year round. Even if we have to access it by snowmobile.
I was thinking we could insulate the tank, sides and top, and place a circulating pump inside the tank, which would run constantly throughout the winter. However, this does not solve the problem of the pipes between the tank and the little cabin freezing. We could possibly run heat tape Along the entire distance between the tank and the cabin but that would be about 20 yards.
We are open to ideas.
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travellerw
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# Posted: 4 Jul 2023 18:54 - Edited by: travellerw
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First.. Is the cabin heated? Otherwise you will need to worry about lines inside too.
What you are asking for is done on mobile buildings in the oilfield all the time. Insulation and heat tape is the solution. Not only the water lines, but the sewer as well. Any liquid carrying line exposed to freezing will need that treatment. (chiseling frozen poo paste out of a frozen sewer line is not something you will want to do)
As to a tank. You could insulate and use heat tape, but you would need a fair amount of power to keep it above freezing in really cold weather.
And.. You would have to worry about losing power when you are not there. Especially if something went wrong that required human intervention (i.e. mouse chews heat tape, breaker trips). Whole lotta expense to fix (the tank could split).
We are in a similar position. Instead we are insulating and taping just the sewer lines. The heat tape will only be powered when we are there. We will bring water with us during the winter months. This means no showers, but we can still use the toilet. Much simpler and cheaper.
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Davpmars
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# Posted: 4 Jul 2023 20:35
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The plan is to heat the cabin but only while they are there.
I got a good laugh at the mental image of someone trying to chisel frozen poop out of the sewer line!
Have you considered a water circulation pump inside the tank to keep the water moving through the winter?
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ICC
Member
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# Posted: 4 Jul 2023 21:48 - Edited by: ICC
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I built the water system in my cabin (northern NM mtns about 8800 ft) like an RV. 12 gallon rv fresh water tank under kitchen counter. RV water heater. RV water pressure pump. Shower and sink. No indoor toilet. I have a nice state approved privy. That means 1 less thing in the cabin that could freeze. My choice and I know it is not everyone's cup of tea. All indoor plumbing is easily drained and blown out with a small air compressor.
There is a underground 325 gal spherical cistern. XPS insulation sheets are laid horizontal about 2 feet under ground level with the sphere under it. Vertical panels of XPS form a ring around the cistern from the horizontal sheets down 32". Joints are can foam sealed.
The sphere has a 4 foot tall manhole extension that protrudes above ground level a foot or so. A 4 ft square box covers the manhole extension. It has 6" thick XPS wall and top insulation. The top is removable and has a closed cell foam air seal. I wanted to be able to access the cistern without digging just in case,
A submerged Rule Inline bilge pump is in the cistern and is used to transfer water to the inside tank.. 12 vdc power from the cabin thru conduit powers the pump. Switch inside cabin. 5/8" hose for the water. Water from the inside tank can be drained back to the cistern with a turn of a valve. Those pumps have no foot valve, so water drains back to the cistern and nothing freezes up. Cistern water runs about 45 to 50 F in the coldest part of winter.
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travellerw
Member
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# Posted: 4 Jul 2023 21:55
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I have considered many options (including a circulation pump down to geo holes). Unfortunately, you are in an better position as me since I don't have grid power. I'm all solar, so limited in the power I can use. I'm also in a much colder area than Utah (it gets to -35C here pretty much every winter).
So, now that I think about it.. You might be a good candidate for a good insulation and heat tape application. It seems the coldest Utah really gets is about -15 to -20C (about 0F).
However, the whole leaving heat tape running with no human around would sketch me out. I wouldn't be ok with that.
Maybe someone who lives in a similar climate will chime in with some better knowledge than me.
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travellerw
Member
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# Posted: 4 Jul 2023 21:59
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P.S. word of advice.. If you do find yourself in the poop chiseling business. Its best to make sure you keep your mouth closed (and please don't ask how I know)
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darz5150
Member
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# Posted: 4 Jul 2023 22:24
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Also, that's why you don't see many plumbers that bite their finger nails! Lol
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Nobadays
Member
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# Posted: 5 Jul 2023 08:16
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ICC ... just what was going to suggest! Small tank in the cabin, drain back to the underground tank when not in use. Great set up!
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mj1angier
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# Posted: 5 Jul 2023 08:49 - Edited by: mj1angier
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Yeah I would set it up so that you can drain the system easily each time you leave. That way you only have to worry about keeping tank from freezing. I think that some form of an immersion heater/ heat element would work to keep it thawed. Doesn't have to keep it hot, just above 38-40F. It's not to hard of a problem with grid power.
Something like this Inkbird (good company, use these a lot in home brewing)
https://www.amazon.com/Inkbird-Max-1200W-Temperature-Controller-Greenhouse/dp/B01HXM5 UAC/ref=sr_1_2_sspa?keywords=water+heater+controller&qid=1688561467&sr=8-2-spons&sp_c sd=d2lkZ2V0TmFtZT1zcF9hdGY&psc=1
Just put sensor in tank and plug in immersion heater and set it to come on around 38F and off at 45F
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gcrank1
Member
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# Posted: 5 Jul 2023 09:53
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We built our 1st cabin in '83-'84 and are on our 2nd since Aug. 2020.
Both have been 'dry', utility water from a roof fed rain barrel (top filtered on input) in season and we bring potable.
One learns how to minimize water use, especially when you carry in, but not an issue if you can 'motor in'.
It has been the two of us with occasional guests.
So, maybe dont make this more complicated than it has to be for a small cabin and starting out? You can figure it out over some time and add in if/when it seems appropriate.
Btw, we have a diy compost privy. It works just fine with no wasteful use of water; LOTs of info online.
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Brettny
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# Posted: 5 Jul 2023 15:45
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Quoting: Davpmars We want to have the property usable year round
Drill a well. To have reliable water in a winter setting and your going to be useing it only on weekends I would expect to need a 1,000gal+ tank. Tank cost plus the price to burry it 8' deep..how much does a well cost?
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travellerw
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# Posted: 5 Jul 2023 16:00
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Quoting: Brettny how much does a well cost?
Its pretty much $10K CAD here (100-125ft, 6 inch casing, pump/screening included). $45 per feet for anything beyond that. Expensive, but not terrible if you are living full time. I couldn't swallow that for a weekend cabin.
Of course you could always do a DIY shallow well for less. Probably not potable, but fine for washing and toilet flushing.
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NorthRick
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# Posted: 5 Jul 2023 16:44
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Quoting: Davpmars The purpose of this post is to get ideas on how to protect it from freezing. From what I have read, we need to bury the tank, a minimum of 8 feet deep to get below the frost line. However, the ground is very rocky so that may not be a possibility. We definitely want to bury the tank but if we cannot get it below the frost line, how would you go about keeping it from freezing through the winter? What would you do?
Foam board insulation. Rule of thumb up here is 1 to 2 inches of foam board thickness equals 1 foot of frost protection. Assuming your frost depth is really 8 feet, and you buried the tank such that the top was 3 feet below the ground surface, lay 5 to 10 inches of foam board over the top before burying it. Extend the foam board horizontally several feet beyond the sides and the ends of the tank. You don't need to add it to the sides of the tank.
As everyone else has said, make sure the whole plumbing system is easy to drain. The piping between the tank and the cabin should be designed to drain back automatically. Heat trace on the line between the tank and the cabin shouldn't be needed but wouldn't be a bad idea to install it just in case.
You do not need a circulation pump in the tank.
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NorthRick
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# Posted: 5 Jul 2023 16:48
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Quoting: travellerw Drill a well. To have reliable water in a winter setting and your going to be useing it only on weekends I would expect to need a 1,000gal+ tank. Tank cost plus the price to burry it 8' deep..how much does a well cost?
We get by on about 7 gallons of water on a weekend. Mostly for doing dishes.
A cabin neighbor up here had a well drilled this winter. Final tab for just the well was $22,000. Buying and burying a tank is a whole lot less than that.
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