When we were researching the idea of sustainable living we discovered the world of rain water recycling. Essentially rainwater water can be used for flushing toilets, washing cars, watering the garden and washing machines.
It’s clear we would need a regular supply from the water board coming into the property to service all our domestic needs (drinking, hand washing, baths etc) but for all other needs we could utilise the abundance of rainwater in this country.
Next we needed to research what was available and the technology involved to make it happen and actually found it’s a relatively simple process to capture and store rainwater. We found local authority grants were available, subject to the installation being carried out by a certified professional.
At Fieldview we decided to get someone in to do the grunt work i.e. dig the hole and put the tank in and we’d sort the connections to the house ourselves. This would mean we’d lose out on the grant but would save considerably on any ‘specialised’ installation costs … pretty much balanced itself out in the end anyway.
Utilising rain water is nothing new, we’ve been doing it for centuries but our minds were brought into sharp focus when we were told by the water board we’d be subject to the installation of a water meter in the new house.
Wow … we’d have to pay based on the amount we consumed! … definitely not something we were used to. With the demands of the garden, Poly Tunnel and a four bedroom house with more than one toilet we knew we’d have to look seriously at how to collect and store sufficient rainwater to cover our needs.
How does a rainwater harvesting system work?
Basically all the water that falls on your roof and into your gutters makes its way to a large plastic tank buried somewhere in the garden via a basic filter system. (Piece of wire mesh inside a plastic housing sitting just inside the top of the tank)
Inside the rainwater tank is a large water pump capable of pumping the contents up to a regular black plastic storage tank usually housed in the loft. Connected to the pump is a 25mm water pipe running back to the controller in the utility room.
On our system we have the pump has a long length of rubber insulated cable which runs all the way back to a flow controller in the utility room.
The flow controller manages the source of the water supply into the loft tank. Essentially if the rainwater runs out, the main water supply into the house kicks in ensuring there is always adequate water supply to the storage tank.
Inside the controller are a couple of solenoids controlling the switching of the supply, simple technologies but extremely effective all the same.
Which system to go for?
There are several specialist companies out there offering systems and most can be found on the web. We spoke to the guys at www.rainwaterharvesting.co.uk who were extremely helpful and recommended we go for a ‘Stored System’. The other main option to go for is a standard direct pumped system where the water is pumped on demand from the storage tank to the controller.
With the ‘on demand’ system if you flush a loo or turn on a garden hose the pump in the rainwater tank kicks in and pumps to the appliances via the controller. Exactly what you would expect but the pump is on and off all the time which puts additional wear on the pump and makes constant demands on the electricity supply.
If you go for the stored water solution (slightly more expensive option) the pump will only kick in when the stored water in the loft is used up, so the pump is on less often and subsequently there is less demand on your electricity supply.
Doesn’t the stored water become stagnant and smell?
Initial fears were soon eliminated when we realised just how much water the average household uses on a day to day basis. The water wouldn’t get a chance to stagnate and the pump takes the water from the top half of the stored water anyway which is typically the cleanest.
Another great feature of the stored system is a built in refresh function. Basically if the stored water remains unused after 3 days the controller takes over and pumps water back into the rainwater tank stirring the contents discouraging bacteria from forming.
We couldn’t see a time when we wouldn’t use the water (other than if we were on holiday .. some chance) and so it wouldn’t have a chance to stagnate.
If there is too much rainfall the tank simply fills up and overflows into a large soak away in much the same was as conventional guttering system.
How much did it cost?
The complete package including everything we needed to store and deliver rainwater to all our appliances cost £2,500. The excavation and installation of the tank cost a further £200. We budgeted £2,500 for the complete system but as we already had the builders on site were installing the septic tank we bit the bullet on the extra £200 to save some time.