In light of the UK government’s recent advice to households to stock up on food and water in anticipation of potential interruption of supplies this winter, I wrote a Mastodon thread on water management without access to the mains which a few people asked me to tun into a blog post. I’m not claiming to be any sort of disaster sanitation expert here but am drawing on my experience of bushcraft and of fieldwork traipsing around the West African bush chasing a small silvery-grey fly. I have had a pretty unusual and frankly fucking weird career path and set of life experiences and hobbies that has probably left me more prepared to deal with interruptions of basic infrastructure than most people in Western Europe, and it turns out some of those skills may be transferable.
I want to start out by saying this feels like a complete delegation of responsibility on the part of the UK government to basically tell households to fend for themselves if the basic necessities of life are interrupted, rather than accepting that it’s the government’s job to ensure that they’re not. I’m going to talk about helpful things that require purchasing, which not everyone can afford to do. There are a lot of households in this country who can’t even afford the food they need today, let alone to stockpile in advance, and that is also a result of the government neglecting its role to look after the people of the country. In the end the best way to be prepared for disaster is not to have a society where most people are a lost job or sudden illness away from crisis in the daily course of events, and we have manifestly failed at doing that.
I also want to be very clear that this is not post about survivalism post civilisational collapse. There have been a few replies to the Mastodon thread in that vein, but this post is not aimed at helping you survive the zombie apocalypse, it’s more aimed at a scenario like the experience of parts of Cornwall that lost access to mains power and water for a couple of weeks after Storm Goretti last winter. All long term forecasts seem to be suggesting that we’re in for a difficult winter in Europe thanks to the most powerful El Nino event on record, supercharged by anthropogenic global warming, so it’s a good idea to be prepared for some interruptions to services. As a species I’d rather we had devoted more of our imaginative resources to preventing apocalypses than planning how to survive them, but here we are.

Water storage
You want to allow 2-4 litres of water per person per day for drinking (the UKgovernment recommendation is 2.5-3 litres). The variation is in terms of age, activity levels (are you cycling around and sweating or sitting at home?) and medical needs. If in doubt err on the higher end. Also remember to allow for pets. You want another litre of water per day per person for washing and cooking. I’ll discuss hygiene in a low water scenario in a subsequent post.
If at all possible you want to be storing water in a dark container, not a white or clear one, to prevent algae growing. We use 20L ex army Jerry Cans for this like https://www.militarykit.com/products/nato-plastic-water-container-20l-black for camps. You used to be able to pick them up for about twenty quid but a quick look today shows the price seems to have jumped to about £40, presumably as a result of everyone panic buying because of the government announcement which is another reason they shouldn’t really have gone “lol, fend for yourselves”. Keep in mind that a 20L can weighs 20kg, so if you don’t have anyone in your household or group capable of lifting that you’re going to need to find something smaller that is food safe, opaque and hasn’t been used to store anything that isn’t food. Someone on mastodon also pointed out that black containers this size are routinely used for storing diesel, so be careful if you’re decanting from them in low light conditions if you’re in a scenario where those could get mixed up.
It may also be helpful to invest in a funnel for filling them, making sure to have a separate one that isn’t used for transferring laundry liquid between containers or anything.
You want to label your water containers with the date you filled them, a pencil on masking tape works fine and won’t wash away if it gets wet. Pure clean water in a sealed dark food safe container shouldn’t grow anything nasty, but will still start tasting bad over time. I’d recommend storing it in the coldest place you have and rotating it out at least every month in cold winter garage temperatures, more frequently in hot weather, but I’ll be honest I haven’t found any conclusive figures on how long long drinking water can safely be stored for so I would appreciate any information anyone else might have.
Several people also pointed out that if you’re storing water as a one off emergency measure, rather than investing in refillable containers that can be taken to bushcraft camps, buying large supermarket bottle of water and storing them in a cool dark place might be a cheaper way to do it. Some people were concerned about microplastics or plasticisers seeping into water if stored in plastic containers. Everyone’s risk calculus is different, but personally I think that lack of water will kill you far faster than microplastics will and mains water is delivered to most households along plastic pipes anyway.
There was also an interesting discussion on Mastodon about the fact that many British houses may still have water storage tanks in the attic and how it might be worth checking and sealing yours against pigeon poo and bat droppings if you have one. The water will still need purifying following the steps below though.
Water purification
If you run out of stored water you’re going to need to start purifying it. This is where the recommendations to start buying a lot of stuff starts mounting up, so where it would be helpful to get together as an apartment block, your street Whatsapp Group, a local Transition Town group, a community kitchen, whatever. I would say that if you take nothing else from this post, the best disaster preparedness tip you can have is to get to know your neighbours. I have this stuff kicking around anyway because I like hiking and wild camping, so if you’re lucky someone in your group will already have it, but if that’s not something anyone’s into this is I’m afraid where it gets expensive.
Water purification is a two step process:
1. Filtration to remove large dirt particles
2. Sterilisation to remove pathogens from the visibly clean looking water produced by filtration.
You can’t skip the first step. Particles of dirt aren’t just unpleasant to drink, they can also make the sterilisation step less effective by enclosing pathogens so the sterilisation agent can’t reach them.
Water filtration
If you’re in a dire emergency you can use lots of layers of cotton cloth or other natural fibres for the filtration step, but if you have the option I’d recommend buying one of these: http://millbankbags.co.uk/ which is a dense fabric bag that filters water under gravity. There are suggestions for other ways of making a water filter here.
You want to keep careful track of which container has dirty water in and which has filtered water in – it sounds obvious but it’s surprising how many highly intelligent people you have to yell at in fieldwork situations for using the same container for the dirty and filtered water.
Water sterilisation
Once you’ve filtered your water it may still be a browny or reddy colour but should be clear not cloudy. This will have removed all the macroscopic particles of dirt but it may still contain microscopic bacteria or protozoa which you now have to kill. Diarrheal diseases are no fun at the best of times, but particularly dire in a situation where you don’t have much water available for personal hygiene and where transmission to other people in close quarters is going to make the situation a lot worse.
For water sterilisation you have three options available to you, and the best one will depend on the situation:
1. Boiling the water
2. Using chemicals eg. water purification drops or tablets
3. Fine filtration.
If you’re going to boil the water you need to be able to do it for at least one minute at a rolling boil to make sure everything is dead. This doesn’t just mean little bubbles forming on the side of the pan, this is big bubbles forming, everything turning over and boiling aggressively for the full minute. Some pathogens like giardia form very tough spore cases that take a long time to penetrate to kill the organism inside. This is also why it’s important to make sure the water is thoroughly filtered, it could take a while for heat to penetrate all the way through a mud particle to a pathogen in the centre say, so if the surface gets a minute at boiling temperature the pathogen itself may only get ten seconds.
This is probably the simplest way of doing it that involves buying the least, but if the power’s out and you’re using a camp stove you’re going to get through fuel very fast this way.
More information on boiling water here.
You can also get water purification tablets that you drop in a litre of water and swirl around occasionally for half an hour. https://www.cotswoldoutdoor.com/p/lifesystems-chlorine-dioxide-water-purification-tablets-E7134007.html?colour=180 These too only work with properly pre-filtered water so the chlorine can reach all the pathogens, none are sheltered inside particles.
Personally I’m not a huge fan because of the taste but that’s because I’ve drunk so much of it over the years. If I was in charge the government would have given some of these to every household alongside suitable water storage and a general emergency kit, but people like me who actually give a shit about solving problems for people don’t tend to end up in charge.
More information about chemical sterilisation here.
Your third option is fine filtration, putting things through a second filter with holes so small microbes can’t pass through them. I know I sound like a broken record here, but even if you use one of these the initial crude filtration step is still very important because it removes big particles that can clog your finer filter and reduce its lifespan.
I’m going to give three options at different price points here, the first two of which work for wild camping too if that’s something you’re interested in exploring.
£30, Lifestraw, a filter you suck water through and it takes the germs out as it goes up https://www.cotswoldoutdoor.com/p/lifestraw-peak-series-personal-water-filter-straw-B4KJ390027.html?colour=108
£100-£200 Katadyn hiking water hand pump filters like https://ultralightoutdoorgear.co.uk/hiker-pro-transparent-water-filter/ I’m biased here, I have an older model of these and I love it. There are warnings about it that the ceramic filter can crack on planes or if knocked and then if you don’t see that it can allow things through, but I’ve never had a problem with mine. It’s also much more convenient than a life straw for filling containers with clean water, and has a little floating mesh bobble you can put at the end of the intake tube to do the initial crude filtration instead of the Millbank bag.
The option we used as a camp, and the option if there are a lot of you coming together as a community kitchen or something, is one of the gravity fed candle style filters that can do litres and litres. You just fill it up, wander off and clean water drips into the bottom tank without you having to do anything. The Rolls Royce of camp kitchen water purification, with a price point to match.
Hygiene in low water situations.
First of all hand washing is still very important. It can be tempting to think you can save a bit of water by slacking off here but that is very much a false economy because the absolutely last thing you want in this scenario is for everyone to get diarrhea. Just trust me here.Hand sanitiser is a way to extend the time between handwashings, not a full replacement. It sterilises the surface of everything it touches, but does not remove dirt particles from your skin which can harbour germs and then come off on food. I was always taught the rule of three – you can use hand sanitiser twice, but the third handwash should always involve soap, water and a nailbrush. And you should always wash your hands with soap and water after poo.
You don’t need running water to wash your hands, a bowl is fine. The low water way is a bit splashy, easiest out doors but you could do it over a bath if you had to. Cup both hands, pick up a handful of water with the hand you didn’t wipe with, pour it into the cupped hand you did, pick up the soap with the cleaner hand, lather up and use the nail brush then scoop more water out of the bowl. With practice you should be able to get clean and rinsed with three handfuls of water and minimal contamination of the bowl. Recommendations for handwashing from Mastodon also included buying something like this or making a hole in a bottle top with a hot needle to make something you could squirt water over your hands with.
You want to be buying medical grade hand sanitiser too, which is 65% ethanol, rather than the regular stuff which is 35%. And it’s better to buy a pack of lots of little bottles than one big bottle, because once you open them the alcohol starts evaporating out and the sterilising power decreases. This stuff is flammable, so keep that in mind when planning storage.
I would also recommend toilet paper gel like https://try.wypeuk.com/ (using the referral code FRIEND-KLEQBZJ2495V might get you a discount on this) or wetwipes as a cheaper but less sustainable alternative if you’re in a situation without enough water to shower for a long time. In terms of general body washing you can do fine in the short term with a flannel and a bowl, if water is very tight focus on pits, bit, face and feet and use a separate cloth for the face part!
Menstruation-wise I used a menstrual cup, but I know a lot of people don’t get on with those so I’d recommend stockpiling disposables over washable period pants just because it takes so much water to wash them.
Sanitation
I don’t really feel like my expertise extends to sanitation in an urban situation which has lost water, all of my experience has been in camp situations where you can dig pit latrines, so much of the following is taken from Dr Merilee Karr’s presentations on disaster sanitation.
As I read it you have three levels of disaster for managing human waste:
- Brief interruption of water supply, plumbing intact.
Continue using the household toilet as normal. If it’s yellow let it mellow, if it’s brown flush it down by pouring undrinkable water down the toilet after it from greywater from handwashing, water butts, flood water, overspill from handwashing etc. Pee smells bad but doesn’t actually transmit germs, it’s poo you have to worry about in that regard.
2. Multi-day interruption of water supply, plumbing intact.
Continue using the toilet for pee, but put paper in a separate sealed bag as it won’t flush away. Pooping in bags. You can buy and stockpile special camping poo bags or commode liners that contain absorbent deodorising gels and pads, but dog poo bags or bin bags work too. Tie them up and seal them well, and store them well away from the house where they won’t be trodden on or broken apart by rodents.
3. Sewage system damaged by flooding or landslide.
This is where you want to get into the construction of separate latrine infrastructure away from the house, one per 20 people. I would recommend checking out the presentations at the above link for far more authoritative instructions than I could provide here.
In all of the above cases, good hand hygiene and washing with water is absolutely vital.
Food and cooking
Although it might be tempting to stockpile cheap bulk dried foods like pasta, beans and rice, these take a lot of water and fuel to cook so I would recommend prioritising the sort of canned or long life pouch food that can be eaten with no or minimal heating. If cooking fuel is scarce, and you’re in a suitable situation to try it, insulation cookery involves bringing food up to temperature for ten minutes or so then wrapping it in some insulating material like a duvet or sleeping bag for long slow cooking. I have a blog post about the technique here.
In conclusion
In a more sensible world the government would be issuing this sort of comprehensive advice, rather than some bonkers woman on the internet who usually talks about bikepacking and growing windowsill sprouts. In a sensible world it would come with answers to questions about how long water could be stored for example, maybe in a handy leaflet delivered to every household alongside water purication tablets, hand santiser, a first aid kit, wind up torch and radio. But the response to covid showed us we don’t live in that world, so we have to look after one another. I sincerely hope no one reading this post has to use the advice in it in earnest this winter, but if you do I hope it’s helpful.
@tangledbankforaging.co.uk is there some text gone missing after the 1, 2, 3, eg before "minute at a rolling boil"?
(Some copy/paste formatting thing perhaps?)
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Yes there was thank you! Fixed now
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@tangledbankforaging.co.uk soz, also before "holes so small microbes can’t pass through them"
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@rooftopjaxx @tangledbankforaging.co.uk thanks, fixed now
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@afewbugs @tangledbankforaging.co.uk
Some sort of M$ list formatting thing?
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@rooftopjaxx @tangledbankforaging.co.uk I'm not sure but I've had a quick look through and I think that's got them all now. Thanks again
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@tangledbankforaging.co.uk
Water storage time:
In the US the conventional advice is to empty and refill containers every 6 months
I just did mine after 5 years
Of 20 containers (reused juice jars), 2 had a bit of mold on the inside of the lid so I threw them out
The rest were all fine, so I rinsed them and refilled them
Unopened bottles of water from the store probably keep even longer
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@tangledbankforaging.co.uk
Food: A friend in my church preparedness group sampled Mountain House freeze dried meals, sold for hiking. She said they were delicious. She was really impressed. They are kind of expensive, though
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