Off Grid Water Supply! Rainwater Collection & Water Pumps!
Over the next few weeks I’m going to talk about all the things that power and run my Tiny House! I’m going to tell you about the off grid, self sufficient components of how my farm and house is run such as the off grid water supply, off grid solar and the septic system. I’ll talk about rubbish collection in a rural area. I’ll let you know all about the plumbing and electrics in my Tiny House as well as the TV and internet connection!
Today let’s talk about off grid rainwater living!
Living with off grid water is easy to do if you can get your design right and have the ability to catch as much rainwater as possible! It tastes better to drink and it’s much nicer to shower with! And once your system is set up there’s no more cost…no water bills!
I am completely off grid with the water supply to my Tiny House and the farm. This means that I am relying on my rainwater tanks and dams for all my household water and for water for all the animals to drink…no mains water connection as a back up! Water can be trucked in when I need it, and I have had water trucked in more than a couple of times!
Rainwater catchment…the way to calculate your potential rainwater catchment is quite easy! As a guide to collection capacity, consider that each 1mm of rainfall = 1 litre of water per square metre of roof area, then allow 15% wastage factor.
My Tiny House is approximately 30sqm so each time I get 1mm of rain I will catch approximately 30 litres of water – 15% wastage so approximately 25 litres of water.
My Shed is approximately 90sqm so each time I get 1mm of rain I will catch approximately 90 litres of water – 15% wastage so approximately 75 litres of water.
So my total rainwater catchment potential from both my roofs (120 sqm) is approximately 100 litres of water per 1mm of rain!
Then you’ll need to find out the annual rainfall in your area to make sure you’ll be able to catch every drop of precious water that rains down! Take into account that you’ll be using the water while it’s collecting but as a guide…if your area has 500mm average annual rainfall and your roof can catch a potential 100 litres of rain per 1mm of rainfall you’d not need more a 50,000 litre rainwater tank capacity!
I’ve got in total 60,000 litres of rainwater tanks, two @ 22,500 and three @ 5,000.
The two larger tanks sit by the sheds, there’s one of the smaller tanks behind my Tiny House and the other two smaller tanks are in the paddocks to fill stock troughs.
Do I get the best rainwater collection possible with how my system is currently set up? No! I’ll tell you why and what I could have done better and how I’m going to change it!
The rainfall in my area is approximately 700mm annually so I can catch roughly 52,500 litres per year from my sheds alone and although my shed tanks are only at 45,000 litre capacity because I’m using the water while it’s collecting the tanks are big enough to collect all the water! These tanks are the main water supply to the house and sheds. There is a water pump on the ground by the tanks that turns on to pump the water through every time you turn on a tap, shower, washing machine etc. If you are installing off grid water and rainwater tanks you’ll need a water pump installed by your plumber and I’d definitely recommend some distance from the house as they are a little noisy!
So where I got it really wrong was my house rainwater tank! The potential annual rainfall catchment from my Tiny House roof is approximately 17,500 litres and I’ve only got a 5,000 litre tank behind my Tiny House! To put anything bigger would have looked too big and I was only thinking aesthetics at the time!
Silly mistake on my part as I’m watching the tank overflow at winter time! And to make it worse is the plumbing design…the tank behind my Tiny House was never hooked up into the house nor is it connected to the main tanks so it’s used solely to fill the horses troughs and I am wasting so much water!
Although I’ve lived solely from rainwater tanks for many years I didn’t think to design this system any differently and I definitely could have done it better! Couple of options I’d recommend…get onto a plumber who is experienced in designing and installing off grid water catchment systems, it’d be a fantastic service for a plumber to offer advice on how to maximise your rainwater catchment and set up the rainwater tanks to work efficiently, each property would need to be individually designed with the occupants needs considered too! Or take the time and do the research yourself to make sure you can maximise your catchment potential! I’ve found great advice and help from a couple of local irrigation shops so check them out too!
Can I fix up what I didn’t do right? Yep, of course I can and I will! I could put a pump next to the tank behind the house and connect it directly to the house to use as a first option tank but the cons are the pump is noisy, it’s costly to buy another pump and then there’s mucking around switching from the tank behind the house to the current larger tanks! Instead I’m going to connect the tank behind the house to the larger tanks via underground pipe so the extra catchment will go straight into the larger tanks! This is still a costly process but will run more efficiently and quietly!
The two 5,000 tanks that are used to pump water from the dams for stock use is a system that runs fantastically! The tanks are connected to self filling stock troughs so the animals can drink from them. When we designed our sheep and horse paddocks part of the design was ensuring drinking water was available in every paddock. We have two large spring fed dams, each of them is set up with a petrol pump that when turned on will pump water into it’s corresponding tank and those tanks gravity feed water into all the troughs on the property. I will go into much more detail about the stock troughs and dam pumps when I post about the paddock design!
Something to also consider when designing your off grid rainwater system is how much water you’ll need! You can check your current water bill to give you an idea of what you currently use. Also don’t forget to take into account the water needed for your animals…you can research the average amounts each animal will drink per day. And if you’re intending to plant trees or a veggie patch allow for the water needed for them too!
Enjoy living with an off grid rainwater system 💦 🚿!
If you have any questions you’d like to ask me please send me an email via the “Contact Me” page on this blog, I’m happy to answer and help as best I can.
Thanks for reading!
Jen 🏡