# Rainwater harvesting



## Advanced Driver (Jun 24, 2006)

I want to build a garage and I am looking at options for a water supply. One option is rainwater harvesting rather that running mains water. As space will be limited, I don't want a large number of water butts for filtering etc., so I was looking at a proper underground storage tank. eg. something like https://www.tanks-direct.co.uk/1500...e=2&fep=2836&gclid=CPugzu2H3NQCFc2d7QodhEUBEw

Is it feasible and is there any special equipment (eg. filters) that would be better? Does anybody know whether these tend to freeze in the Winter?


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## Forsh (Jun 13, 2014)

I'd be surprised if frost gets more than an inch down in Berkshire - no it wont freeze

My garden used to flood so I dug a soak-away but it was in clay and didn't work so I dug the gravel out and I buried a water butt, drilled 1" holes all round the base and back filled around the butt with gravel I'd dug out and dropped an aldi dirty water pump in it and piped it through a 3/4" strainer and to a brass hose lock connector. And built a patio over it, it sits below the water table and supplies water to water the plants and jet wash the flags

https://www.toolstation.com/shop/Plumbing/d20/Valves/sd2696/Inline+Y+Filter/p68822

400 microns filter is fine for a pressure washer according to the email response I got from Karcher


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## Bigpikle (May 21, 2007)

you can buy modular tanks designed to fit under a patio or similar - they dont require a big hole as they are fairly shallow, but cover a bigger area. Alternatively big a massive great hole for a single tank. They dont freeze under ground as it never gets cold enough in this country. There are loadsof pumps and kits available to supply all sorts of needs, but they arent cheap as they designed to a high quality since you dont want to keep digging up your garden every year to fix a cheapo pump.

Just do some googling on harvesting rain water and you'll find loads of options - not a very cost effective way to do it though if its just for the car and watering plants. You'd be better off doing a full house system and getting a proper return - assuming thats cost effective for your property..


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## Bulkhead (Oct 17, 2007)

I have a similar set up and can share some details. Firstly, it doesn't look like a pump is included. You'll need a fully submersible pump with a decent pressure and flow and these aren't cheap. I paid almost $800AU so I'd imagine these would be around 400 quid. I also have a solenoid switching mechanism that you may need. The tank has a run-off filter to stop stuff like leaves etc. from getting into the tank. The pump has a further filter that you need to clean now and then so make sure it's accessible. Then I have a canister filter (25 microns) after the pump (ours supplies the toilets so needs to be clear). We also have a primer that diverts the first bit of water down a drain - this is to prevent dirt that has collected on the roof from being washed into the tank. It's also worth raising the pump off the floor so it doesn't draw any settled dirt into it. Our first pump gave up after four years as it was placed on the bottom of the tank. Not quite the same conditions as the UK but a few things to consider.


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