Household water storage / treatment facilities for cold climate

Hello everyone.

I live in a cold climate, zone 6, where ground can be frozen solid (but not very deep) for 1-2 months.
The local building codes dictate 80cm as frost line but it's actually not that deep.
If it freezes to 30cm deep it's a very hard winter.

So, what about the water ?
There are two sides to it.
1. Rainwater storage
2. Graywater treatment

1. Rainwater storage
This water could be very useful for washing so it does not need to be drinking quality.
Where to store it ?
Well, underground seems like a good idea, especially if a large volume is needed.
So, how to build IT ?
Plastic underground reservoirs are expensive and ... they're plastic.
Stainless steel is maybe even more expensive ?
A pit lined with EPDM ?
A pit lined with clay (my soil is very clayey) ?
What else ?
Something that's preferably reliable and long lasting, easy to do, cheap, in this order.
Reliable and ong lasting is mandatory.

2. Graywater treatment
A sand / gravel / reed / bulrush bed seems like the way to go.
Basically a trench filled with sand / gravel, with overflow, where reed / bulrush grow, in which graywater is poured via pipe.
Since i live in a cold climate, this will freeze if outdoors.
That's not an issue actually since in nature it freezes all the time.
But if it's frozen it can't accept any graywater anymore.
Since i want to build a lean-to greenhouse, i might place the treatment ditch inside.
But reed grows very tall, might shade everything.
I might cut it down each winter but the whole thing will take precious space.

Any experience / ideas for this scenario ?

We have a sister church in Romania and my understanding is recycled brick or cement block is readily available. Could you upscale that to build an underground rain water catchment system? I know a lot of Permie People dislike cement block and brick, but if it is recycled (or upcycled) then its rather okay in my book.

As for treating grey water, here in the USA and particularly Maine where we get frozen soil much longer, it is often treated by filtering the grey water through wood chips. Wood chips rob the water of nitrates especially. Since the open spaces allow the water to drain without freezing, you could drain your grey water into a pile pf wood chips and thus treatment would take place.

I agree with the wood chip suggestion rather than gravel. I think it's more long lasting and robust -- you can just add more wood chips when they rot down, instead of having to dig gravel out and clean it. Maybe you could consider an underground soak pit for winter and a surface treatment with a pit pit filled with wood chips for the other three seasons. Having your greywater as close to the surface as possible, or on the surface, is best for keeping the aerobic organisms thriving, which treat the greywater fastest and make its nutrients available to plant roots.

For the rainwater tank, if long lasting is a top priority and it's only to be used for washing, personally I'd go with the buried plastic tank idea. It sounds more robust and foolproof than epdm film or clay. Actually I'm planning to use a plastic tank for my drinking water too. I hope that whatever is currently allowed to be used in drinking water tanks doesn't turn out in the future to have been leaching toxins! Underground, the tank shouldn't be getting very warm, and leaching usually happens less at cool temperatures, so that's another excuse... Well, it also depends on your budget and how strongly you feel about/against plastic.

Wood chips wont freeze because:

The incoming grey water melts any ice
There will be little ice because the water peculates through the wood chips
The wood chips are decomposing and are producing heat, as long as the pile is of sufficient size, heat will be generated

Rebecca Norman wrote: I hope that whatever is currently allowed to be used in drinking water tanks doesn't turn out in the future to have been leaching toxins!

Bingo.
Besides, plastic tanks are not THAT cheap.

The thing with gravel/sand is that it's more readily available.
Plus, i want to plant reed / bulrush / cattail in it.
The sand bed was used successfully by romans and modern systems plant the above plants in it to avoid the cleaning you mentioned.

Travis,
How would you go about using wood chips ?
How and in what are they going to "reside" ?
I can imagine a box filled with woodchips, without bottom or with some mesh, and greywater is dispersed on top.
Underneath this box can be a long trench filled with gravel and the above plants could go here, of course, after the box.
Please give more details on how it's done so i have a better mental image.

My neighbors have a bed of cattails that they send their greywater to. Quite possibly the blackwater effluent from their septic passes through there... but I am not totally sure. Where I live it is best to assume none of the septic systems are up to code. The plumbing in my house relied on sending all sink water to a gravel pit and allowing it to run into ditches down slope. Often this means water runs through every yard in the neighborhood, and my well water is suspect. You might feel bad for me... but don't! I am seeing the possibility here of making the wet low-lying part of my yard into a wetland reclamation area, and since my own home is built on a hillside I have ideas now for how I can reduce the problem my neighborhood seems to be having, with their conventional but probably not well percolated systems.

These ideas with the wood chips sound great for graywater... I can imagine hiding them into a raised garden bed, with ornamentals on top, and the percolation chips down below, with a pipe that drains out into an open wetland down hill or built just below with reeds. I have a meadow-beside-the-house, wetland downslope, idea in mind. Where no effluence flows I plan to create a pond... this near my well and to include crushed stone filtration... that is going to be my catchment system for non-drinking water, but I will use it mainly in the garden. My well... has issues. I have to remedy them. Its not such great water, nor is it scarce, that I need to worry about conserving it. What I do need to worry about is protecting it from the pollution of the landscape.

I plan to use woodchips as a material for an extended driveway loop... this is going to be a meadow-forest edge inspired front, to serve to buffer noise and runoff pollution from road and create a place to park... since I dream of turning my home into a bed and breakfast in the future.

A friend of mine likes building with sandbags, he has an ordinary plastic tank and basically builds around it with these sandbags (old produce store bags sewn close) and at the end he renders it. Like that when there is no UV the plastic lasts very long. Metal tanks are much nicer and much more expensive. We use the rainwater for everything and we are still alive. The problem with the plastic tanks is that they only live that long.

Lawrence, great that you figured out your situation and possible solutions.

Angelika, that sounds like an above the ground system which i'll have problems with during winter, unless i place it in the greenhouse to double as thermal mass and hope it does not freeze..

My situation is similar to Britt Lawrence's neighbours. The ground here freezes for a long time, so I have what I call a "dam" inside on the pipe that the greywater (with a tiny amount of black water from the composting toilet -- don't tell) flows through. I close the dam at bedtime & open it back up in the morning. It took two seasons to get just the right size of pit so it doesn't overflow. The pipe goes to a small 'pond' that I dug at the bottom of the small hill closest to my house. I have willows growing in it & want to get some cattails going this year. This summer I'll make a short living willow fedge around it to keep dogs and their toys from getting into the pond.

I just have a couple of barrels attached to the eave downspouts for rain water. There's a very long hose going from one barrel to my real pond at the back of the property. In the winter, I disconnect the hose and turn the barrel upside down until spring.

Hi Jane.

Sounds like you got your system pretty well established.
My property is a postage stamp thing ... not much space so everything has to be placed optimally.
Definitely no place for large trees like willow, especially since only the southern side is free / available.
Placing anything big there will negate any solar gain i planned.
Much more so since willows shed they're leaves long time after frosts start and get green as soon as frosts are not permanent anymore.

I do get a lot of rains at around freezing weather, maybe one or two degrees above it.
If i were to store the rainwater in tanks/barrels in my greenhouse to also double as thermal mass, the cold outside water will not be very nice to be sent into the greenhouse.
And i might get a lot of rain this way so it can be a thermal problem.

If i just let the downspouts flow somewhere for the entire winter, that's going to be a lot of water.
Water that:
- i might not want to drown the remaining of the property with (unless i want to make a skating ring)
- i might want to use for other purposes like washing

My property is only a quarter acre going downhill from the road; tiny compared to most people here.

I have to turn the rain barrels over before freezing weather as the water in them would freeze otherwise and any new water would run off it into the basement. I don't have a greenhouse or I'd try to figure something out for that. A skating rink sounds wonderful!

My willows are basketry willows; most don't grow very big and I harvest them each Spring before they begin to bud. Some day I'll actually get around to making baskets, but for now I use some for my fedges, I give some away to whoever wants to grow some, and the rest are piled up in an outbuilding waiting for me to soak them and make useful things.

There are lots of things I'd love to do if I had the money and was 20 years younger (I'm 68).

For rainwater storage, can you find a used hot water tank?  Sometimes these show up on Craigslist here.

Have you looked into a "first flush diverter" for the rainwater?  They're supposed to keep leaves and other gunk out of the water.

If you set up a rainwater tank inside a greenhouse, I'm sure you could add a simple valve so that when the tank is full the rainwater is diverted to a different location.  That would keep you from losing all the warm water in the tank when cold rains come.

Jane, i have 2 thirds of what you have and people consider it large-ish.
I find it a little claustrophobic but it's better than living in a 4th level studio.

Steven, you'd be surprised how frugal we are around here.
No such thing as used tanks, those are too valuable.

The first flush diverter is something i'll use, mainly to get rid of the dust / dirt / bird droppings that will come down with the first drops of rain.
Diverting water when the tank is full is easy peasy but also not the issue.
The issue is that i want to divert the water if it's much colder than the greenhouse tank.
That requires a temperature sensor connected to a valve.
I would prefer something simpler, maybe a manual valve i switch depending on how cold i feel the rain is going to be.
This is simple but dependent on me being there ...

Anyway, all this is speculation until i settle on a solution.

PS
If i use 8 x 130 gallon barrels (HDPE) i'm at half the price as if i buy a 1000 gallon tank.
But 8 barrels will take a lot more space than a tank ...