A Simple Guide to Harvesting Rainwater

With 2018 registering the joint hottest UK summer on record, we could be in for another scorcher this year – and rainfall may be thin on the ground. With this in mind, you may wish to consider collecting rainwater during the early months of 2019, ensuring you’re not left short during the summer.

What is rainwater harvesting?

Put simply, rainwater harvesting involves the collection and storing of rainwater for future use. Once collected, rainwater can be purified to use for drinking and cooking or used for other purposes such as flushing toilets or watering plants and gardens – and is particularly useful in areas where rainfall is scarce.

Although it can be implemented on an industrial scale using advanced methods, you can easily harvest rainwater at home. In theory this could be as simple as catching the rainfall in a barrel – in fact, this basic technique has been used in rural areas for centuries, well before infrastructure was designed to collect rainwater in large quantities.

The law around rainwater harvesting in the UK

Although rainwater harvesting is illegal in many countries, including parts of the United States, it remains legal in the UK. In fact, many water companies encourage people to collect rainwater where possible in order to ensure they aren’t affected by heatwaves and droughts during summer.

Rainwater harvesting is, however, subject to strict regulation in the UK. The Water Regulations Advisory Scheme (WRAS) regulates mains water supplies, and this includes any fittings which connect to your mains water. So, if you have a rainwater harvesting system which interacts with the mains water supply at your home or workplace, there are rules to adhere to.

One of the key regulations governing the practice of rainwater harvesting is that you must maintain a physical air gap between the mains supply and the harvested water in order to prevent backflow of rainwater contaminating the mains supply. The WRAS also asserts that the pipes which contain and transport your harvested rainwater must be clearly marked as non-potable (ie. not suitable for drinking).

What are the advantages of rainwater harvesting?

While we’ve already established that rainwater harvesting is a simple and effective way of ensuring you’re not inconvenienced by a lack of rainfall during the summer months, there are numerous other benefits to consider as well. For example, harvesting rainfall is an easy way of reducing your water bill, particularly if you are watering your garden or plants as the water does not need to be treated prior to use.

It is also beneficial to the environment, as your supply of drinkable water is not easily-renewable and is better saved for drinking than used for watering gardens, where untreated water is sufficient. In fact, saving water is a benefit generally, particularly as the UK population continues to increase, placing a greater burden on our public water supply.

One further benefit of rainwater harvesting is its impact on storm water retention; water that is retained in barrels or other storage systems during periods of heavy rain lowers the volume flowing into our public drainage system, reducing the risk of flooding.

How to collect rainwater

Collecting rainwater can be as simple as placing a receptacle anywhere likely to receive heavy rainfall. However, there are more advanced systems available for maximising the efficiency of your harvesting.

Most systems use the in-built collecting properties of your home or workplace – rain which hits the roof will usually flow down through gutters and downpipes, so the placement of a storage tank at the exit point of these pipes is an effective way of collecting large quantities of water.

A filter will be required to remove leaves and other debris, while modern engineering methods allow you to purify and transfer the collected water to non-potable applications elsewhere on the premises

How can you use harvested rainwater?

There are numerous ways to make good use of harvested rainwater. Rather than waste drinkable water from your taps, you could use your collected rainwater to water your garden. In the summer months, your lawns and plants can suffer from a lack of rain, so storing water during rainy periods is an ideal way of ensuring they remain healthy and hydrated. You can even use it to fill your ponds – unlike your mains supply, rainwater is free of chlorine and therefore better for fish and other wildlife.

Inside the home, one of the most common uses of harvested rainwater is for flushing toilets, while the lack of chemicals in collected water makes it ideal for washing clothes (although you’ll need to purify it first). Filtered rainwater is suitable for most cleaning uses, including washing your car – although we recommend not using it for your baths or showers, as it can contain unhealthy bacteria.

At Drain Doctor, we can advise on the most cost-effective ways to harvest rainwater at your premises, and assist with the installation of specialist systems designed for the collection and re-use of rainwater. So, if you’re thinking about installing a rainwater harvesting system, get in touch today.