May 152012

This map shows the variation between expected average rainfall (clear white) and actual rainfall for the first four months of 2012. 0% is dark brown, 200% is dark green. Clearly there's a huge divergence between average and actual rainfall.

We started off an earlier article about rainwater (see ‘An Overlooked Source of Water‘) by suggesting that a few 55 gallon drums of water taken from your downspouts would be a great source of emergency water in a Level 1 type, at-home, emergency.

If you’re planning for a short duration Level 1 situation, then you don’t need a lot of water, and even a single 55 gallon drum of rainwater would probably be enough – albeit on an uncomfortable hardship type basis – for a week or so, and larger quantities will allow you to enjoy successively more ‘creature comforts’ (such as flushing toilets).

But what about Level 2/3 situations – possibly a year or longer, when you need to be self-contained in everything you eat or drink?  A 55 gallon drum of water doesn’t go very far in that sort of case, does it!

Unless you’re in an area where it rains reliably every day, you’ll need to have some storage to give you water on the days when it doesn’t rain.  We talk about how much storage you might need in our article How Much Rain Water Can You/Should You Store.  This article concerns it more with appreciating how much water you can actually get from your roof collection system and matching it to your consumption level.

This and the other articles about rainwater storage might seem a bit complicated, and we deliberately go into quite a lot of detail.  But – what is more important than water in your life?  Sure, you don’t want to run out of food either, and shelter is important too, but if you don’t have a reliable supply of water, you’ve chosen the wrong place to shelter, and you’ll die of thirst long before you die of starvation.

Water is also a great comfort item.  Whether it be for enjoying a long soak in a tub of water, or singing in the shower, or just washing our clothing more regularly than arguably essential, a positive supply of water translates to a much improved quality of life.

So please do bear with us, and if you end up needing further advice or assistance, by all means contact us.

Water Consumption Rate

The first issue is the rate at which you will use water.  This is a very ‘elastic’ number, because in the worst case scenario, you can live on just a quart or two of water a day for some time.  But in a best case scenario, living a normal life such as most of us do at present, you’ll be going through as much as 100 or more gallons a day (true – look at your water bills the next few times you receive them and do the math yourself).

So somewhere between less than one and more than one hundred gallons of water a day is a number you can settle on as an appropriate compromise between cost and convenience.  Deciding on the exact number is outside the scope of this article – you need to decide what the number is, and then we’ll work forward from that.

For the sake of this example, let’s say you want 10 gallons of water for each of three people, and another 20 gallons of water for household things in general – 50 gallons a day for all of you, combined.

Agricultural Water

There’s another thing to consider as well.  While in a Level 2 situation you are basically surviving on your stored food supplies, in a Level 3 situation, you’re needing to grow your own food into the future.

And if you thought your personal and household needs for water were high, you ain’t seen nothing yet.  Here’s an interesting table of water requirements in terms of cubic meters of water per metric tonne of food yielded.

The numbers are very imprecise (even though they seem exact) because it is hard to know how much of the needed water can be supplied from the moisture in the ground to start with and how much needs to be added.  But just to seize some numbers off the site and convert them to US measures, you’re looking at almost 2,000 gallons of water per pound of steak you end up with after raising cattle, 700 gallons for a pound of pork meat, and ‘only’ 200 gallons per pound of wheat.

Our discussion that follows is primarily to do with domestic water for your residence.  But in choosing your retreat location, have an eye for what you’ll be growing there and what the water needs for that will be, too.

In most cases, it will be close to essential to have access to a free-flowing spring or a gravity fed water source to support your farming needs.  We can’t stress this too strongly.  Everything in an ongoing Level 3 situation revolves around convenient access to water.

Equating Consumption to Rainfall

You know – sort of – how many gallons of water you need per day.  But what does this translate to in terms of inches of rain?

The first thing you need to know is the collection area of your roof.  Don’t ask a roofer to do this for you, because he will probably tell you the number of ‘squares’ of tiles needed to lay your roof.  Because your roof is on an angle, the surface area of the roof is appreciably larger than the square feet of floor plan it covers.

So measure the exterior of your house, and add extra space for any roof extensions out over the sides of your house, and from these dimensions calculate the footprint on the ground of your roof.

You also should adjust for any areas of roof which don’t feed the rain into gutters.  Clearly if the water just runs off the side of the roof, it does you no good unless you add extra guttering.  If you have a separate garage and roof and plan to collect the water from that, include that in your calculation, too.

Let’s say you have 1400 sq ft of roof area, and the two sides which the roof slopes down to are each 40 ft long.  Maybe you have a couple of 5′ gaps where the water just runs off the side, but the other 70 ft in total are guttered.  So 70/80 * 1400 means you have 1225 net sq ft of collection area.

One inch of rain falling on 1000 sq ft of roof will deposit 623 gallons of water.  So each inch of rain on your roof will have 763 gallons of water going down your downspouts.

That is the theoretical best case outcome for this scenario.  We’ll fine tune it for the real world, but let’s first do a quick reality check before going any further.

In our example, you want 50 gallons of water a day, and you’ll collect 763 gallons of water from every inch of rain.  This means that in a year, you’ll consume 18,250 gallons of water, which will require 24 inches of rain (best case scenario).

Have a quick look at the average rainfall data for your region (see links below).  Just using the very basic annual rainfall average number, how much rainfall does your region get?  If the answer is less than 24″, you know that you’re either going to have to cut back on your water use, or you’re going to have to find additional sources of water.

Is Rainwater a Practical Partial or Complete Solution

Now for one further quick thought.  Maybe your region will give you 15″ or maybe even 30″ of water.  15″ is good – you could get 63% of your water needs from rainwater.  That’s great.  And obviously 30″ is brilliant.

But what say you can only expect 6″ of rain a year?  And what say none of that rain falls in June, July, August or September, and less than you’ll consume in May and October?  That means you’ll need to stockpile perhaps 7600 gallons of water in May to see you through to some time in October.  That’s a lot of storage, and a lot of cost.

Being as how you have already determined that you’ll need a well or some other water source, if you find a reasonable well (anything over a 2 gallon/hour well will be perfectly adequate – most wells will give you more than 2 gallons/minute!) is it really worth while also investing into a rainwater collection system?

Our recommendation would probably be to continue with your rainwater system, unless you were drawing water from a free-flowing spring or taking it via a gravity feed from a reliable clean year-round river.

There’s one interesting thing about rainwater.  It typically falls in months where solar and wind energy is the lowest – the winter months.  So maybe you use a solar/wind powered pump to draw up water from a well in the summer months, when you have plenty of energy but not much rainwater, and in the winter months, you use rainwater at a time when you have plenty of rain but not much energy.  The two sources balance each other out nicely.

In a Level 3 situation, you’ll be on your own for the foreseeable future with only the resources you have at hand.  Energy will be terribly scarce, as will spare parts for water pumps, and anything you can do to use as much low tech/energy free resources to  help extend the useful life you can get from energy powered and higher tech solutions is to be considered as compelling.  After all, once your high-tech gadgets are gone, they’re probably gone for good.

Furthermore, you know you can trust the water you collect from your roof. Well water is probably okay, as long as you know what else is happening to the water table, but river water depends on what is upstream of you – something you mightn’t be able to control.  That herd of deer that likes to go down to the river to drink?  Guess what else they do at the same time?  The camp set up by the less well prepared survivors of the city a mile up-river?  What do you think they do to their sewage?  Yup – you’re drinking it.

For all reasons, we urge you to keep a month or more’s emergency supply of water on hand – what say your well’s pump breaks, or the river dries up or ices over for the first time in 50 years?

So if you have some tankerage already in place for a reserve supply of water, why not use it to collect the rainwater you get as a supplementary source of water whenever possible, to save on your water pump and the energy needed to drive it.

Real World Imperfections in Water Collection

Remember back to our theoretical collection of 623 gallons of water for every 1000 sq ft of collection area (ie roof)?  Well, now let’s start considering some of the imperfections that reduced the true net water you actually get in your tank from the rain that falls on your roof.

What say you have a very light drizzle on a warm windy day?  What say your roof is made of wood shakes?  Maybe the first bit of rain will soak into the wood, and maybe the warm wind will evaporate most of the light drizzle before it forms into sufficiently large droplets on the roof to start tumbling down and into the gutters.

Maybe you have some dirt, leaves, moss, or debris of any other sort on your roof (and in your gutters) that soaks up some of the water too.

Whatever the circumstance, it should be obvious that a very light drizzle, while possibly adding up to a measurable amount of rain over some hours, might actually be entirely uncollectable.

The steeper the pitch of your roof, the less rain you need to get the water started running down and into the gutters.  If you have a smooth impervious substance like tile or metal, the water will run more readily than if you have a textured or slightly absorbent material such as artificial or natural wood shakes.

For months when the amount of rain that falls is probably less than the minimum you need, these issues become relevant.  You need to analyze how the rain falls, on a daily basis (or even hourly but this is probably not readily available) to determine how much of the rain will end up being collected and how much will be lost.

Our own experimenting has suggested that the first 0.01″ (one hundredth of an inch) of rain is lost, and if the rain is falling very slowly, there will be appreciable ongoing losses.  A 1″ downpour, all within an hour, will give you close to 100% water recovery, but a fine drizzle totaling 1″ over two days might see you only collect half the water (this is a WAG on our part!).

Storage Losses

You know that water boils at 212°, and if you think about it for a moment, you also know that water evaporates, without boiling, at lower temperatures too.  Even a lump of ice loses some of its mass each day due to evaporation.

How much water will you lose out of your tanks due to evaporative losses?  This depends on the ratio of the surface area of the tank to the volume of water within it, the amount of open space above the water, the temperature of the water and of the air (the two might be very different), the ambient humidity, and if there are any winds blowing over the surface of the water.  It even depends on the altitude you are at.

That is enough variables to make it very difficult to offer up for sure always accurate rules of thumb for calculating evaporative water losses.  Suffice it to say that the cooler you keep your water, and the more enclosed you can keep the top of it, and the smaller the surface area as a proportion to water stored, the lower your water losses.  You can’t really control the outside temperature or humidity, but you can stop winds from blowing over your water (and over any openings) and you can perhaps insulate the tank some and maybe even bury some or all of it to take advantage of the natural tendency of the ground to be cooler in summer (and warmer in winter, too – you don’t want your water and pipes freezing up come winter-time).

If you’d like to see an excellent worked through formula, you can go to this webpage which concludes that a typical cup of water would take 44 days to evaporate in a still room at 72°.  In other words, it is sort of evaporating at a rate of 2.3% a day, at least for the first day.

Let’s use the same formula and basic data, but instead say we had the cup of water outside at 85°, and the humidity was 40% rather than 60%, and there was perhaps a light 3 mph breeze running across the top of the water.  This would give us a massively different result – the water would be gone in 11 1/4 days!  You’re losing almost 10% of the water every day.

Clearly, the rate of evaporative loss can be a huge factor and has to be carefully optimized.  Let’s say you can limit your evaporative losses to 1% a day with careful design.  But this does mean that if you need 1000 gallons at the end of 30 days, you’ll need to start off with 1300 gallons at the beginning of the month.  That’s a significant impact.  And if you’re storing 10,000 gallons to last you six months, if you’re experiencing even ‘only’ a 0.5% loss a day, that comes to 9,000 gallons.  Yup – you’ll lose 9,000 of your 10,000 gallons just to evaporation.

Okay, we are slightly simplifying things here, but you see the issue.  The most important thing to obsess over in designing your water storage system is the evaporative loss of your stored water.

Water Collection Rate

So you need (in the case of our worked example) 50 gallons of water a day, right.  Let’s run the risk of stating the obvious, and make two assumptions.

First, if you are getting more than 50 gallons coming down your downspouts each day, you’re free of problems.

Second, it doesn’t rain every day.  Even if you average 50 gallons a day of water collected, you’ll probably be getting less in the summer and more in the winter, and you’ll have occasional unseasonably dry spells that you’ll need to plan for.  Sure, you might get some unseasonably wet spells too, but they are not so relevant.

You need a buffer of stored water to carry you over the dry days with no rain or insufficient rain.  How big a buffer should that be?

It all depends on the rainfall pattern in your local area.  You’ll need to go off and do some research to get not just monthly average rainfall numbers, but hopefully daily rainfall data and averages for many years.

How do you do this?  Well, we’re glad you asked that question!  Please now visit our article How Much Rainwater Can You/Should You Store for a detailed working through of how this can be analyzed and calculated.

May 142012

A simple but impressive rainwater collection system.

A person can survive on much less than a gallon of water a day in an emergency (the actual amount depends on things like the type of food you might be eating, the work you are doing, the temperature and humidity of your environment, and your height, weight and age).

But a common rule of thumb is that in an adverse situation, you should plan on about 1 gallon of water, per person, per day.  This keeps you from being dehydrated, and gives you extra water to cook in, and even some to brush your teeth with, too.

But you don’t get any to flush with.  Even modern low flow toilets use 1.6 gallons every time you flush.

The real-world amount of water we actually use in our comfortable lives every day is much greater than the essential need for several pints to keep dehydration at bay.  In addition to toilet flushing, there is dish washing, clothes washing, showers and baths, car washing, garden watering, and who knows what else.  Estimates vary enormously, and there are doubtless regional variations, but it seems the average American uses between 50 – 100 gallons of fresh water every day.

In a Level 1 event, you are going to want to ‘hunker down’ at home for as much as a week (much more than that and you’re moving into Level 2 territory).  The chances are high that you’ll have water, the same as always.  But that is far from guaranteed.  Maybe you have experienced an earthquake that has broken the water mains, for example.  Or a major power outage that means no electricity to drive the water pumps that send the water to your faucets.

Part of the hope in a Level 1 event is that you can continue to live a reasonably normal life during the short-term nature of the event, and due to the event’s anticipated short-term, you choose to stock enough essentials to ensure as much of your comfort as you wish.

So what should you do about water?  And, if you’re going to store some, how should you do so?

It seems to be prudent to keep at least enough water to allow for the essential ingredients of life to continue – maybe a gallon per person per day for essential uses, and some more for not quite so essential uses such as toilet flushing and at least sponge baths.  (Do we need to remind you of the old saying ‘If its yellow, let it mellow; if its brown, flush it down’?)

So maybe you decide you want to have 10 gallons, per person, per day, and maybe you want to be sure to have a ten day supply for three people.  That’s quite a lot of water – 300 gallons.  To look at it another way, that’s over a ton of water, and with the weight of the containers that hold it, you’re probably up to a ton and a half.  (Water weighs 8.35lb per US gallon.)

One more perspective on this 300 gallon supply.  If you’ve been saving up 2 liter drink bottles to keep water in, you’ll need 568 bottles to hold 300 gallons (there are 3.785 liters in a US gallon of water).

Well, don’t let us stop you from buying plenty of 2 liter bottles of Coke, and some industrial grade shelving to stack and stock your water supplies on.  But there’s one source of water, and one easy way of storing it, that most people overlook.


If you live in a dwelling with a roof (ie not in an apartment complex) your house or condo’s roof can be a great rainwater collector.  Best of all, most of what you need is already there; you don’t need to make many modifications at all to be able to get the rain from the roof and into storage.

To encourage you some more, here’s an interesting statistic.  For every 1,000 sq ft of roof area, your roof will collect 623 gallons of water from each inch of rainfall.  Or, to put it another way, with three people each wishing for 10 gallons of water a day, you need a daily average of only 1/20th of an inch of rain.  Well, actually, that wouldn’t work, because 1/20th of an inch of rain would just wet the roof rather than run off it to be collected, but you get the point, I’m sure.

Better to say that if you had 1/2 an inch of rain fall once every ten days, each 300 sq ft of roof would supply enough water for one person.

Okay, point taken.  If you live somewhere wet (like Seattle!) then here’s one of the good sides to this – even the driest month of July still sees 0.79″ of rain, and apart from August at 0.97″, all the other months are way over an inch of rainfall.  But you probably know that, ‘unscientifically’, just from living here, don’t you!

How to Collect Rainwater

This is dead simple.  Although you can do more complicated things, all you need to do is put a rainwater barrel in your downspouts.  There are a couple of things you can do to make this more useful, however.

The first thing is that you want to have your barrels up as high as possible, so you can gravity feed the water on from the barrel to where you’ll be using it, and the more the height differential, the more the pressure from the water in the barrel down to wherever the water eventually comes out of a tap.

From the point of view of the rain coming off the roof, it makes no difference at all if the barrel is immediately under the eaves, or sunk into the ground.

Don’t put the barrel ridiculously high up, though, because you’re going to need some way to get water out of the barrel as and when needed.  The simplest consideration involves two things.  First, you want to be able to reach a tap on the bottom of the barrel.  Second, you want to be able to run a hose from the tap, through a window, and into your house, with hopefully the hose able to run downhill all the way, even if only on a gentle slope.

You also don’t want to get too carried away with scaffolding to support barrels way up the side of your house, and maybe some of the people in your family won’t think they’re the most appealing of ornaments either.

So work out whatever you can as best you can.  Chances are you have several downspouts around the perimeter of your house, you’ll want to do this at as many of them as you feel motivated to tackle.

This water is also great for the garden too, and if you have a fair amount of collection capacity, it might be useful to use it for gardening, in dry months, especially if your local water authority adds any sort of restrictions or surcharges on ‘excessive’ water use.

Water Barrels

You can collect water in anything you like that is reasonably big, which doesn’t leak too much, and which doesn’t add nasty flavors or chemicals to the water.

Most people will choose plastic food grade type barrels.  These can be purchased new (of course) and sometimes used – they are recycled barrels that held some sort of food product or chemical, and which the supplier may or may not promise to have fully cleaned, although often you’ll see that in one point they talk about ‘triple cleaning’ the barrels, and at another point, they also recommend against using them for storing drinking water.

For non-drinking water purposes, used barrels are fine.  But for drinking water, and unless you want to have to either accept some strange flavors or treat/purify the water, it is probably best to get brand new barrels.

Some people will quite rightly avoid plastic entirely, and have the budget to spring for stainless steel.  Others might use galvanized iron, or even wood (probably not a good idea – don’t let wood dry out too much or else it will shrink and the barrel becomes less water-tight).  Fiberglass works.  Glass is great, but sadly impractical.  You can even make water barrels (more like tanks, really) from concrete if you’re wanting something huge in size.

Whatever type of container you get, it is wise to thoroughly rinse and sanitize it (them) before putting water in them.

Choose an opaque color.  Sunlight is as bad for water storage as it is for anything/everything else, so try and keep the water dark (and ideally cool, too, but that might be asking for a bit much).

As for the size of the barrel, there’s no right or wrong answer to that.  Well, clearly there are upper and lower limits – below a certain size and it isn’t worth the bother, and above a certain size and you’ll never fill it.  If you’re looking at typical sized 30 – 55 gallon drum, you will probably end up with close on your target 300 gallons of water, all stored ‘automatically’ for you outside.

A 55 gallon plastic drum, full of water, will probably weigh about 470 lbs – plus the weight of the structure it is mounted on, of course. A 30 gallon drum would be more like 260 lbs.  Both are way too heavy to ever carry, but the 30 gal drum has the benefit of not needing quite as strong a support structure.

Plastic water barrels will cost you anywhere from less than 50c to more than $2 per gallon of storage capacity, depending on the type, their fittings, and where you source them from.

Multiple Barrels Per Downspout

If you wanted to, you could also put multiple barrels, side by side, at each collection point.  Simply run a pipe between the bottom/lower side of one barrel to the same place on the other barrel.  The two barrels will fill evenly and subsequently empty evenly, too.

Alternatively, you could stack one above the other.  If the bottom barrel can be sealed, you simply run a pipe from the bottom of the top barrel to the top of the second barrel, and you take your water out of the double barrel from a pipe at the bottom of the lower barrel.

If the second barrel is not watertight, you’d want the connector to go from the overflow point on the top barrel down to anywhere on the bottom barrel, and you’d then need two points to take the water out from – the bottom of the top barrel and the bottom of the second barrel.  Maybe the lower barrel is below the window or whatever, and you designate this as your ’emergency spare’ and also for garden water, whereas the top barrel with the more convenient water flow is for your main indoor needs.

Connecting Your Barrel to Your Downspouting

This is easy.  Cut and divert your downspouting so that the water pours into the top of your barrel.  Arrange a generous sized overflow tube, also at the top of the barrel to allow overflow water, after the barrel is full, to then go back into the rest of your downspouting.

Be careful that the water coming into the barrel doesn’t just go straight into the overflow exit pipe.

At the bottom of the barrel, you’ll want to fit (or have fitted for you) a regular outdoor tap with a thread for regular hose, so you can then take the water from the barrel, probably via a regular hose, and into the house (or wherever else you want to use it).

Modify as needed if you are having two or more barrels linked together.

Linking Your Barrels Together

This is a great idea.  Maybe you have four downspouts, and a barrel at each one.  Rather than have four hoses all leading into your house, you could instead link the four barrels together and just have one hose, from whichever is the most convenient barrel, to feed into your house.

Simply run a hose from the bottom of each barrel to the bottom of each other barrel.  The hose can even go down to ground level before going up again to the next barrel, it doesn’t really matter, because the rate of water flow through these balancing/transfer hoses can be reasonably low.

For this to work it is important that the barrels be at close to the same height off the ground.  You are making use of the magical property of water to settle at the same level, even if in multiple barrels in multiple locations.  You can easily test the relative heights just by filling all the barrels with about an inch or two of water (so they don’t get too heavy).  You should see the same amount of water in each barrel.  If one has more water in it than the others, you need to raise it however many inches to balance it to the others.

Is Rainwater from the Roof Safe to Drink

Many people enjoy long and healthy lives drinking untreated rainwater from their roofs.

Indeed, when the writer was a child, he lived for some years in a town where his parent’s house relied exclusively on rainwater.  The roof was made from painted corrugated iron, and the water tanks were of galvanized iron.  He remembers as a little boy playing with the tanks, and never thinking to question the dirt in the gutters that the rainwater passed through, or all the slime and sludge in the bottom of the tanks.

Birds would fly overhead and do what they do, and who knows what else happened to the water as well.  It was not treated in any way; it just went straight from the roof to the holding tanks, and from them to the taps inside (this was well before people started drinking bottled water – 100% of all our water came from the tanks).

There are some common sense issues to consider, however.  Try and keep your water away from zinc (such as sometimes used to reduce moss growth), from lead (in paint or flashings), and from treated timbers.  Any sort of new roof should be treated warily before it has had plenty of rain rinse it off.  You don’t want any overflow or discharge pipes from hot water tanks or a/c units to drain onto the roof and potentially into your water tanks.

Screening the tanks can help prevent large (and small) insects and animals get into your tanks.

If you’re in a polluted area, you have a bit more reason to be validly concerned.  All that pollution up in the air slowly settles down, and some of it lands on your roof.  Rain then washes it into your water tanks.

One rule of thumb is that if the water looks clean, smells clean and tastes clean, it is probably fine to drink, especially for a limited period of time.  But if you are concerned about pollution being washed into the water, or just don’t like the thought of drinking water from your dirty roof, by all means filter and treat the water before drinking it.  Or use your outdoor water for non-drinking purposes (cleaning and toilet flushing) and supplement it with the gallon per day of water you feel to be better for drinking purposes.

One plus about rainwater.  Depending on how you might choose to treat/purify it (sometime it would be great to understand how adding chemicals to water is considered to be purification!), you’ll be getting water with no fluoride added to it, no chlorine, and no other nasty chemicals that may or may not have harmful side effects.

Rainwater is generally ‘soft’ rather than ‘hard’.

How Much Water Should You Store

This very essential aspect to do with planning a rainwater system deserves its own page.  And so it now has one – please see How to Calculate How Much Rainwater You Should Store for a mind-numbingly thorough discussion on this point.

 How Long Can You Store Water?

This might seem like a strange question.  Water is just water, right?  H2O.  What can go ‘stale’ with water?

Well, yes, in a perfect world, that is true.  But inevitably, you get biological contamination, and also some other contamination that might become food for the biological contamination.  Add some sun and some nice warm conditions, and even clean pure water will eventually end up with algae and other types of biological contamination.

As the water falls through the air, it picks up contaminants.  It picks up more as it runs over the roof and into your storage.  So rainwater can be somewhat biologically active to start with.

Furthermore, there is always the danger of chemicals leaching out of plastic storage containers and into the water.  This happens slowly over time, so the longer water stays in the same plastic container (and the warmer the temperature and the more the sun) the more leaching will occur.  Smaller containers have a greater surface area to volume ratio, and so need to be emptied and refilled more frequently than larger containers.

Some people recommend changing any stored water once a year.  Others say they’ve had no problems with ‘old’ water many years old.

For ourselves, the nice thing about rainwater is that (depending on your rainfall, storage capacity, and usage patterns) you’re probably turning over the water in your tanks more than once a year anyway.  We definitely renew the plastic bottled water we have indoors every year or so, but the outside water, as long as it is being sort of renewed – either just by surplus rainwater overflowing out of the barrels, or from garden watering and refilling – we don’t worry about, especially if it is water that isn’t our prime drinking water to start with.

Maintaining the Barrels

There’s not a lot that you need to do to maintain the barrels.  Check for leaks, especially around the taps.  Maybe once every five or so years, if you see visible accumulations of algae and sludge in the barrels, clean them out.

An easy way of cleaning the barrels is to use a siphon and just move the end of the siphon tube that is in the tank around to suck up the stuff from the bottom of the barrel.  You won’t need to completely empty the barrel that way.

Needless to say, such activities are best done at a time when rain is forecast in the foreseeable future so as to be able to replenish your water stocks (but there’s no need to do it in the middle of the downpour!).

Legal Issues

Alas, in some jurisdictions, the water that falls on your roof of your house, on your property, may not belong to you!  Anxious environmentalists may be concerned that you are diverting the water from its ‘normal’ path to wherever it would otherwise go (let’s ignore than a house and roof creates an un-normal water collecting/concentrating point to start with, shall we….).

In other states with water shortages and complex water rights, it has been argued that by collecting the rainwater, you are stopping it from mysteriously migrating on to the state’s water supply, and therefore, you are depriving the owners of the water rights of their water (this is definitely the case in Colorado).

The simple act of building structures to hold water barrels may require building permits too.


Adding a water collection facility to your roof’s downspouting can be an easy project you can do yourself, and will provide you with a store of extra water, either for personal use in a Level 1 emergency, or simply to water your garden with and place less stress on the town water system.

There is one difficult paradox – the months when you most need water are the months when it rains the least.  This means that you’ll need to have somewhat larger storage capacity (from the wet months) to carry you through the dry months.