How to Harvest and Store Rainwater: Our Off-Grid Water Supply
When we first bought our current property and decided to live off the grid, we had only two water-storage tanks. We knew it would be important to harvest and store rainwater as part of our strategy for sustainable living. Rain fell on our roof, ran into the gutters, and was diverted into the tanks. One caught water from the house. The other was positioned near a small shed.
The house storage tank was larger, yet it was quickly overflowing during days of heavy rain. We watched a lot of water being wasted as it spilled from the overflow outlet and spread across the grass.
With no connection to town water, we are entirely dependent on harvesting and storing rainwater. Because our plans included orchards and vegetable gardens, we had to improve and increase our water storing capacity to have any hope of surviving periods of drought.
Another concern was how we would cope in the event of a bush fire. Fire fighting requires water. Until we successfully harvested and stored more rainwater, we certainly wouldn't have enough water to save our home in an emergency.
One of Our First Rainwater Storage Tanks
Off-Grid Water Supply
If you live off-grid as I do, and rely entirely on the water supply you manage to harvest and store during the rainy season, you'll need to be able to move your water around during a lengthy dry period.
There's lots of things you need to learn if you want to live off the grid. One of them is that water doesn't run up hill. It often surprises me how many former city-dwellers don't know that.
Preparing for Drought and Long Dry Spells
It wasn't long before we were setting money aside to purchase a much larger storage tank (25,000 litres). It made no sense to waste rainwater when it was abundant. We would need every drop we could save once the long dry season began.
By positioning the new big tank downhill from the house tank, we were able to transfer water to it using gravity.
Turn on the hose, wait until the water reaches the end of it. Then quickly shove the hose through the hole in the top of the big tank and push it down until its end reaches near the bottom of the tank. (In other words, the water comes out at a level lower than the water level in the smaller tank higher up the hill.)
Whenever we were confident there was more rain on the way, we transferred water from our house tank. (Sometimes waiting until it actually began raining before connecting the hoses.) We would drain about 50% of the stored water into our new storage tank.
Water Without a Pump
Water Transfer Pumps
Gravity feeding worked well until the level of water in the big tank reached the height of the water in the upper tank. That's when we knew we needed a water transfer pump to continue our 'top up' system.
The greatest benefit of water transfer pumps is during the inconvenience of long dry spells. Additional water in a big storage tank is of little benefit if you can only access it with a bucket.
With a transfer pump, we were also able to position a small tank above the level of the house roof, into which we pump water for gravity feeding into the toilet.
Unlike the standard water pump we use for pressure to operate the shower, kitchen taps etc, the Water Transfer Pump takes a larger hose fitting and gets the job done in a much shorter time.
Note: Before buying yourself a water transfer pump, please look at the photo so there is no confusion. This is not the kind of little transfer pump used in a fish pond. If you want to harvest and store rainwater, you'll need a real pump.
Water Transfer Pump in Action
Do you collect and store rainwater for your own use?
My Mobile Water Tank
Shortly after we bought this property, we planted rows of trees and bushes to act as a windbreak on two of our boundary fences, thinking it would only be necessary to bucket water them for a short while before the rainy season arrived and nature took care of them.
The rains however proved unpredictable. Instead of evenly spaced showers, we had months of no rain.
Every day throughout summer I made the time to walk buckets of water from the dam to a few of the trees. Regretting that they were positioned beyond the reach of hoses and wishing I had a mobile water tank. It could take a week to water the last of them, and then I began at the first tree again.
As regular readers would know, I am a great believer in finding - and following - an easier option to complete any task whenever possible. I have also been known to be slightly eccentric in my approach to some things. lol. I suspect my solution to watering the distant trees is a combination of both those traits.
No longer registered for use on the roads, a small box trailer sat beneath a gum tree. My husband was storing some cement blocks in it. I noticed the trailer as we were discussing where to position our latest acquisition of another 1,000-litre storage tank. It was one of those light bulb moments.
Hey presto. Suddenly we have a mobile water tank. We can tow the trailer to the dam, pump the tank full of water and, having adapted its outlet to accommodate a hose, can drive to individual trees and water them.
If you plan to harvest and store rainwater for an off-grid water supply, a mobile water tank could also work well for you.
How We Water Distant Trees :)
Increasing the Size of Your Water Storage System
For most of us, budget is the deciding factor when purchasing rainwater storage tanks. It makes sense to begin with a tank you can afford and then build on your system when you have cash to spare.
Available space is also a factor. If you cannot fit that huge water tank in your backyard, there's no point buying it. Time to get creative.
A friend of mine has a whole series of smaller water tanks jammed into the space alongside one side of her house, and the nicest garden in her area. Rainwater runs from her roof into one tank but because they are all interconnected, when the first one is full the overflow starts filling the next one. She has a tap installed at the base of each tank, and moves her garden hose from one to another throughout the long summer.
Even if you are on the grid and connected to your town's water supply, you can save rainwater in tanks for using in your garden.
Big Shed, Big Water Tank
Nature's Water Storage Tank
Water is essential to support life. We bought our small farm with the intention of living off the grid, growing fruit and vegetables, raising a limited number of animals, harvesting and storing our own water, and living as sustainably and self-sufficiently as possible.
It was clear that success on the farm would be influenced by our ability to collect and store rainwater, so our first major expense was the construction of a dam.
Fortunately, part of our property is largely clay - providing the ideal location to dig a large hole for water storage. We chose to dig there because the clay itself could be worked to make it watertight without needing to purchase any external liner to stop the water from leaking away.
The dam is very deep with steep sides, designed to reduce evaporation and provide us with a nice place to swim. We did not design it for animals to drink directly from the dam. (If they fell in when it is full, they'd definitely drown.)
My husband built a shed alongside the dam, added a gutter and diverted rainfall into the dam. Every time it rains, nature's water storage tank is automatically topped up. The disadvantage of its location is that our main vegetable gardens and orchards are uphill from the dam.
Dirty Water Pump
It took nearly a full year to collect enough rain to effectively fill the dam, at which time we bought a submersible 'dirty water pump' to enable us to pump water directly to the gardens and orchards using a generator when required.
Dirty water pumps are designed to allow dirt, mud, clay and other small particles to pass through the pump without breaking it. This type of pump requires an external power supply. I cannot run power from my house to my dam (the distance is too great) so I use a generator to run it - but because we live off the grid, we intend to set up a solar option to power it within the next year.
My first choice is to use water from uphill storage tanks (allowing gravity feed to the gardens, so no need for a generator). So we tend to only pump water from the dam when it is becoming too full. It is very reassuring, however, to know that even in a drought we should have enough water to continue growing our own food for years.
Pumping Dirty Water from the Dam
Dirty Water - Better Safe Than Sorry
Using Stored Rainwater in an Emergency
In the event of a bushfire, our plan is to evacuate safely and head for the nearest town. However, living in the bush has an inherent risk of being caught in an unexpected fire. On an extremely hot, windy day a fire that starts within the vicinity of our home could put us in danger faster than we could escape.
Hopefully we will never have to try to extinguish a fire but we are determined to keep sufficient rainwater stored to be available for fighting fires if needed.
- A Water Transfer Pump is not technically a fire-fighting pump, but in an emergency it would be a great help. The Water Transfer Pump has its own fuel tank and engine.
- In a fire situation, we could also use our Dirty Water Pump and pump a strong flow of water from our dam, but it requires connection to a generator. An extra complication.
- We have a tap and hose connected outdoors to our internal water system so we can also access water from our house tank if necessary. Again, a pump would have to be running.
- If all else fails or if we wake in the middle of the night to the thunderous sound of a bushfire close by with no time for escape, we will take refuge in our home-made underground fire bunker. Alongside the bunker is a thick plastic water tank holding about 5,000 litres of rainwater easily gravity fed into and over the fire bunker. In the event the plastic tank melts in the heat of a wildfire, the escaping water should drench the earth and grass on the lower (most vulnerable) side of the fire bunker.
Where Our Water Storage Tanks Are Currently Located
Alongside north side of house.
Rainwater run off from (half) house roof.
Gravity-feeds into the house including kitchen when more than half full, plus pumped as needed into hot water service, shower etc.
Near north tank.
Overflow from main tank falls into this smaller tank.
Water nearby herb and vegetable gardens.
Alongside south side of house.
Rainwater run off from other half of house roof.
Drinking water. Kept full throughout summer as this tank is also close to our fire bunker. Ready to fill water storage containers within fire bunker (and wet bunker vicinity) if needed.
Downhill from house/alongside carport. (Standard tap outlet plus fire fighting connector ready for large fire hoses.)
Our biggest storage tank (25,000 litres). We initially fed this one with water from house tanks when they were full and more rain was expected, but we recently connected it to catch water directly from a roof area. This tank is generally kept full.
Gravity feed to orchard and western vege gardens. Pump into other tanks when their levels are low. Kept at least half-full at all times, ready for fire fighting.
(Raised tank) alongside bathroom's external wall.
Water pumped into it once a month from other tanks.
Gravity feeds into toilet cistern.
Rainwater from greenhouse roof.
Water seedlings and plants in and around greenhouse.
Both sides of garden shed.
Rainwater from garden shed roof.
Water vegetable gardens.
Alongside chook house.
Rainwater from the hen house roof.
Water for the chickens.
Alongside pig pen.
Gravity-fed via hose from north-side house tank.
Drinking water for pigs. Nipple attachment lets pigs drink directly.
Mobile water tank (on old trailer).
Water pumped from our dam (using a 'dirty water pump).
Tow it to water new trees being established along boundary fences.
The Dam. Not techically a tank, but it collects and stores lots of rainwater.
Rainfall. Run off from a large garden shed.
We have a 'dirty water pump' that allows us to pump water out of the dam, then hose it directly onto our vegetable gardens, orchards etc with a 60 metre hose length.
Where Collecting Rainwater Is Illegal
In some states in the USA including Utah, Washington and Colorado, collecting rainwater is illegal.
I can understand the reason for laws prohibiting people from blocking the flow of a river because others downstream have a right to expect the river follow its natural course, but preventing people from harvesting water that falls over their own land is ridiculous.
Rain is a gift from nature, as is the breeze that blows gently through the trees. Raging wildfires, cyclones, hurricanes etc are not so much a gift, but just like the sunshine that warms the earth, nature chooses when and where they fall.
If a government takes 'ownership' of rainfall in a particular region and makes harvesting and storing rainwater illegal, residents should object.
The owner of a dog is expected to control it. The owner of weather - including rain - should similarly be expected to 'control' it.
Here's a few ideas for demonstrating the idiocy of such a law ...
- Threaten to sue the government every time a roof leaks.
- Hold the government responsible for any and all flood damage within the State.
- Urge the government to take similar responsibility for all wind damage, sun damage, fire damage etc if they deem themselves the 'owners' of what you always considered to be the responsibility of nature.
If I lived in such a region I'd enjoy the fun of contacting the government during every heavy downpour. "Control your rain! It's ruining my harvest of chia seeds!"
Every few weeks I'd call to say, "I don't want any rain over my house on Saturday. I'm planning a garden party."
"You say you own the rain," I'd be reminding them, "but I own my house. I don't want your rain over my house. If you want your rain to touch my roof, you're going to have to compensate me."
And if any puddles remained, even after a light shower of rain, I'd be calling to insist, "You'd better get around here and clean up the mess. Your rain has made crossing the road slippery and dangerous!"
If enough residents could be encouraged to participate in this type of campaign, I suspect any law against harvesting and storing rainwater would quickly be revised.
Start to Harvest and Store Rainwater
Whether you live in the city or the country, off-grid or connected to your local water supply, it makes sense to harvest and store rainwater. Especially if you enjoy gardening.
Watch out for specials throughout the year, but try to have your first water storage tanks installed before your next rainy season. As you experience the benefits of harvesting your own water, I suspect you'll be eager to add more tanks.
There will be an initial cash outlay, but this is an investment in your future self-sufficiency and sustainability. As water becomes more costly and scarce in your region during future drought periods, you'll be glad you're a rainwater harvester. :)
Top Tanks: Not Discreet But Very Effective
Water Storage Tank for Your Garden
This article is accurate and true to the best of the author’s knowledge. Content is for informational or entertainment purposes only and does not substitute for personal counsel or professional advice in business, financial, legal, or technical matters.
Questions & Answers
We need to feed water into a permanently located camper. Do we have to put a pump in the water tank to get pressure inside the camper?
You’ll need some kind of pump connected to your water tank, yes. Unless you’re catching water from the roof of a nearby building and can locate your water tank high enough to make use of gravity feed. But I think that’s unlikely so you should look for a little water pump.Helpful 2
What brand of water tanks for off-grid water supply do you use?
I have a diverse range of water tanks. I suggest you approach a local supplier. Show them my photos and they’ll tell you what they have that’s similar.Helpful 2
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