Your own rooftop rainwater harvesting system: the essentials
Whether you’re a keen gardener looking for chlorine-free water for your plants or want to reduce your water bill, a rainwater harvesting system can be a great way to reduce your environmental footprint and potentially save you money. Here’s the Plumberparts quick guide on how to do it!
What you need for a rooftop rainwater harvesting system
The five components of a rooftop rainwater harvesting system are:
1. Catchment area
2. Gutters and pipes to carry the water away
3. Mesh (to filter debris)
4. One or more water tanks
5. Delivery to your destination (this one’s optional)
You typically harvest the rainwater from your roof. It’s already got a large surface and guttering, plus it’s out of the way. Bonus!
For the most basic set-up, you just need to add mesh to filter out the leaves, sticks and other debris from mother nature, a water butt or storage tank and pipework between your guttering and butt/tank and you’re ready to give your garden some extra watery love.
Using rainwater inside your home
You can use rainwater in your home anywhere that it won’t come into human contact. That rules out using it for showering, drinking and cooking. However, there’s still plenty of scope for using it to flush toilets and run washing machines.
Happily, there are rainwater harvesting systems out there that filter the rainwater before sending it to a tank. Some use underground tanks and others are fitted in your loft. If your tank is underground, you’ll need a pump to move the water into your home; a loft tank will be gravity-fed.
Rainwater harvesting systems can save you money on your water bills – especially when you consider they can supply toilets which is where most of your water waste goes. They can also provide water to your home and garden during a hose pipe ban (you’re exempt if you collect water to use throughout the year), prevent flooding through run off water and even help get your new build or extension approved by building planners – they like sustainability!
There are a few different types of catchment systems for rainwater harvesting but all of them work on the same principle: collect water, store in a cool and dark place (this helps to prevent Legionella) and then pump to the outlets. In the UK, you can only supply washing machines, garden hoses and toilets. This means if you’re going to install in an existing property updating the plumbing could be costly.
You’ll also need to use rainwater harvesting pipe (black with four green stripes) between the tank and the home. This makes it clear that the water in the pipe is NOT purified. Some of the simpler systems can be fitted by a competent DIYer, but for others you’ll need to call in the pros.