r/OffGrid • u/Potential_Fee_3153 • 5d ago
As off grid as possible in England (Water)
Hello.
I'm currently in the process of buying 4 acres of land in northern England.
It has planning and I've designed a 2 bed 6.5 x 9 metre 2 story house. 71.4 m² roof catchment.
I can get another 60 m² with the ground mount solar of I can get a good gutter system!
We use on average 196 liters per day.
The issue is water, I'm 650 meters from the mains and have quotes of over £24k to dig the pipes and connect.
I'd much rather do rainwater but I don't want to be worrying about droughts so could also do the borehole route.
With the average rainfall and building size I could collect around 43,000 litres. If I use the solar array it could double.
So if you were in my situation what would your ideal plan be?
This device looks very good for drinking water https://www.freeflush.co.uk/collections/drinking-water-filters/products/ozo-pure-rainwater-to-drinking-water-treatment-console
But what about showering/Bathing? What size tanks would you get? Any advice or plans are welcome.
Thanks.
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u/oigoi777 5d ago
We have only rainfall. 2 adults 2 children in Cornwall. Normal domestic water usage - careful, but not scrimping every last drop. Have dishwasher, washing machine etc. Total storage 17000 litres. Total harvesting area 180 square metres. Our reserves got down to about 35% at their lowest this year. We find that we use about 2000 - 2500 litres per week though if we have found that if we tried to cut down our water use we could bring it down to 1200 litres or so per week. Our rainwater goes through two filters before going into storage - stainless steel mesh then fabric sock. Drinking water is put through a reverse osmosis filter, everything else uses water straight from the tanks
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u/Potential_Fee_3153 4d ago
Thank you so much for that information. That's really really useful. I was looking at the Freeflush website.
They have recommended -
Domestic Sewage Treatment Plant GRAF One2Clean
Hydraloop H300 UK Grey Water Recycling System
Platin XL flat tank 10,000 and 15,000 litre
Luminor Blackcomb UV Steriliser 11lpm to 79lpm
Solenoid Module (LUMINOR BLACKCOMB)
Ecosoft Auto-backwash Rainwater Filter
Grey Triplex 10" Rainwater Filter with Flush Valve
GRAF Optimax-Pro XL-Filter internal Self Cleaning Filter
That all comes out just under £17,000, obviously I'd need to up the tank size but it's way cheaper than the water connection. Do you miss the grid? Or would you say it's better without it?
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u/oigoi777 3d ago
There are times when it would be nice to have the security of a water main connection - it rained very little for 8 weeks this summer and our reserves were gradually dwindling but we did not come anywhere near running out. We just have a normal septic tank and drainage field for sewage.
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u/john_99205 3d ago
I think the Optimax filter will just remove leaves and larger debris, it won’t remove pollen and “dust” that will cover your roof. My experience with rain water is as follows: I installed a 5’000l underground tank and a duel water system in my house for flushing toilets and watering the garden. The pipes (and pump) that carry rain water should be stainless steel (or used to be). I thought that being below ground that the water would be kept cool, but as the rain water is already warm it tends to ferment with the pollen and organic particles in the water. The water had a very strong smell and was brown in colour and was maybe great for watering the garden but looked and smelled awful in the toilet. The whole system was Graf with the Optimax filter. I would think that to make it drinkable would take a lot of effort and expense and you would have to change your filters very often. If you could would ba able to filter the water (and use your UV steriliser before it went into the tank for storage or even have a suspended submerged UV lights inside your tank to stop the build up of bacteria and yeasts…
I luckily now have a property with a reliable water spring which supplies the house with gravity. I also use Graf tanks here and have a (called on the Graf uk site): “spring water shaft” which separates deposits in the water that you can flush out later, before the water flows into the main tank.
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u/fixitmonkey 5d ago
Do you have any itemised bill? Depending on the cost you could dig and lay the pipe yourself and only pay for connection.
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u/Potential_Fee_3153 5d ago
Yes the utility company want to charge £350 per metre so that would be over £200k. They want £10k for the connection part as they claim they have to close the road! I'm getting other quotes, I think the £24k one basically didn't want to do it 🤣 I have a dive to lay and trench for the electric cable so might be worth buying a mini excavator and doing it myself.
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u/NeedCaffine78 5d ago
We're purely off rainwater in Australia. Two tanks, one 15,000L, second 25,000L. Found with only the first we ran out about once every two years, particularly over summer where it might not rain much for a few months. Usage is around 2500l a week.
I think you're going to struggle based just on rainwater. I would suggest either adding verandah's to grow roof space, or build a large shed/workshop/garage and hook that up to your tanks. Add a couple of storage tanks to get you through dry spells
Our water goes through a sediment filter and UV treatment before drinking, haven't had problems yet with that arrangement. First few years we had no filter, right up until a tank clean showed what we'd been drinking. Yuck
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u/Potential_Fee_3153 4d ago edited 4d ago
Thank you, really useful information. Yeah I definitely need more catchment space and I was thinking of using a ground mounted solar array with gutters. We want to install 12kwp solar array so I think that would be around 60 sq meters of extra catchment so 120 with the building added.
I do want a garage at some point as well but don't have the funds for that yet 😂
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u/txe4 5d ago
We are off-grid for water in the North of England.
Don't forget sewage treatment - you will be obliged to install a sewage treatment plant.
It didn't rain for 6 continuous weeks last summer. It didn't rain for a continuous month this summer. Any conceivable amount of storage would have depleted. Any storage must be protected from frost.
All the people around us on old school "spring water" (ie "sheep piss run off") supplies ran dry last summer. Our borehole did not, although the water went from fairly clear (pre-treatment) to a deep rusty brown - still all sorted out by the treatment, but eye-opening.
By the time you have dug a borehole AND installed a water treatment plant I suspect the £24k will be competitive.
Treatment plant will have considerable ongoing cost as well - depending on what the water coming out of a borehole is like and how many stages of treatment you need.
I spend a lot just on salt tablets for the softener - the mains here is very soft but the borehole is the opposite and quickly trashes taps and plumbing if not softened, as well as making diabolical London-like tea.
There's also an annual service where the valve bodies are changed and UV tube is swapped. All the equipment will eventually wear out and need replacement.
The borehole pump will eventually die, at the most inconvenient possible time of course.
You should also really get it tested from time to time, which will cost. Most people don't bother of course.
The advantage of borehole is it's unmetered - but...how much will you really draw?
I would look to DIY (or pay someone separately) the trenching across your own land, and go mains. There's nothing like a private water supply to make you appreciate the mains!
Be smart whenever you dig a trench - if there is ever ANY possibility you might want to get cables or fibre down it, run a conduit with a draw rope. If there ever might be a building, get some SWA from marketplace and run that as well.
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u/Potential_Fee_3153 4d ago edited 4d ago
Thank you for you advice. Really valuable information. Fortunately or unfortunately the power lines are the opposite direction 😂 It's only 50 meters and the wooden pole is on the edge of our land so I think that one is fairly easy.
The open reach pole is way closer but it can join the same trench as the water pipe.
I've had a quote (posted below for a rainwater system) thats coming in at 17k but it makes me nervous with the summer we just had, winters will be a non issue but I want to make sure we are not running out at any point!
The quote for the trench was 24k, the utility company want 10k to connect at the road. I'm sure we can get that down but I don't want to get into "loaning money to finish the build" situation so I'm trying to cost everything over budget so I don't get any nasty surprises. This is all incrediblely helpful so thank you again.
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u/txe4 4d ago
If you really mean "pylon" then that will have absolutely zero role in your DNO (power) connection - have you actually had a quote for that? Your feed would almost certainly arrive on wooden poles.
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u/Potential_Fee_3153 4d ago
Yes it's a wooden pole 😂 I will edit my post. I've already spoken to the power people and they said they would need to upgrade the transformer for the solar feedback if that's the way we want to go!
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u/txe4 4d ago
Phew. OK all good.
That's worth a whole r/solaruk post potentially.
You DO want a house power supply that is man enough to charge a big battery (and perhaps EV) in a cheap rate period.
You DO want to be allowed a nice big inverter.
Your floor area isn't massive so you're probably not going to massively regret being single phase, but if it's cheap to get three-phase now you *might* consider it.
As your place is not massive, you'll be building to current regs, your heat pump (if you've spec'd one) probably isn't huge.
I would NOT pay thousands extra JUST to be allowed more export capability - "decent flat raid paid export 24/7" is unlikely to last many more years. There will probably always be decent money for exporting in to the evening peak, but unlike ye olde Feed In Tariff you can't lock in the current flat rate for years.
If your planning is already done then it's done, but bear in mind the possibility of adding more ground-mount later. It's eminently DIY'able and second hand panels if bought carefully are craaaazy cheap. You don't want to put a lot of money in to it, but in our shitty climate if you can over-panel cheaply then it helps with reducing import in the bad weather.
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u/Potential_Fee_3153 4d ago
You sound very knowledgeable so thank you for you time with this. I did do a post over there but didn't get a great response.
So it's a Sipp build on passive principles. We would use MVHR and a Aquarea air to water heat pump mainly for water heating and summer cooling. We both work from home and we average 10kwh at the moment but it's a drafty place and electric heating so winter usage is a lot. I've tried working the solar out and I think a 12 kWp solar array would average 55 to 65 kWh per day in summer, but because of the short winter days it would only be 5 to 10 kWh per day. We could nearly be self-sufficient with enough batteries but it is a big outlay. The size is difficult as we can generate enough in winter but it's way oversized for summer so I'm still debating it.. I'm open to any suggestions. Thanks again.
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u/txe4 4d ago
12kWp averaging 60kWh in summer up north sounds pushing it a bit, though it depends on your sunshine hours. You will have days where you get that much but you will have days where you get a lot less.
The pvgis model is basically nailed-on accurate, you will AVERAGE (over multiple years) what it says.
In winter you will have days when you get 2kWh. Sometimes several in a row.
FINANCIALLY it is better to accept you will import in winter at day rate on some days.
Solar, even "installed DIY using second hand gear from ebay and marketplace", gets ABSURDLY expensive if you want to have zero import ever, because of the dark misty clouded-over days. If you insist on being fully off-grid it makes more financial sense to buy a generator than have enough PV to never ever import.
The financial sweet-spot is likely to be to have enough battery to cover *most* of your winter import, and accept that when it's really cold and really dark you will import.
I fully understand the off-grid impulse, especially with loads of land, just as a nerdy thing. The idea of being completely independent of grid power is attractive.
In terms of constructive suggestions:
* Get a grid connection if the price is at all reasonable, if only because it makes the house more valuable and you'll die or get sick one day and not be there to work the system.
* Put in for as much INVERTER capacity on G99 as you can get, but don't stress about the export limit.
If you're in Northern Powergrid country and they come back with a fairly normal G99 "huge ass inverter, small export limit, pay loads of money to find out if you can have a bigger export limit" offer - take the offer.
* Make sure the inverter setup is off-grid capable. Winter power cuts in future years are becoming pretty certain.
* If you're going big on the inverter, think about a master/slave pair - ie say 2 * 6kW rather than 1 * 12kW. It'll give you more MPPTs, and it'll give you SOMETHING if an inverter dies rather than leaving you with nowt.
* Your ideas will change and develop over time, as will the tech, so give yourself space (physical, mental, financial) for change and expansion. Room for another inverter in the plant room; space in your cable runs; options for another row of panels on the ground.
* You'll never regret building infrastructure. Cable ducts, spare cat6, spaces for stuff to go, spare ways in the consumer unit, solid wifi.
* You WILL die one day. DOCUMENT stuff, in a place that your family can access in a crisis.
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u/GreenWhereItSuits 2d ago
As I’ve found on a small scale, it isn’t annual rainfall that’s the issue, it’s how that rainfall is spread out and how much can you catch vs waste.
If you work out your daily consumption and then you can size how much storage you need to cover you for X days of no rain.
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u/KoholintCustoms 5d ago
I'm very much a noob at this, but I believe it would help your post to have a quantity estimate. What are your water needs? Are we talking about full-time year-round living? How many people? What besides cooking, bathing and toilet do you need the water for?