This is the complete guide to the rules and regulations of harvesting rainwater in the UK.

In this new guide, you’ll learn everything there is to know about the legality of harvesting rainwater, including:

  • Is it illegal to collect rainwater?
  • What regulations do I need to follow when collecting rainwater?
  • How can I use harvested rainwater?

So, if you’re looking to cut down water bills or help the environment, this is the guide for you.

Let’s get started.

Is it Illegal to Collect Rainwater?

The short answer is, no. It is perfectly legal to collect and harvest rainwater in the UK. In fact, many water companies and councils (specifically in the South East of England) will actively encourage communities to harvest rainwater.

The idea or belief that it’s “illegal to harvest rainwater” comes from the United States, where some states have specific water rights dating back over 150 years. Fortunately, the UK has no such laws and it is perfectly legal to collect water that falls on your property.

Rainwater Harvesting Regulations

Just because it’s legal to harvest rainwater, doesn’t mean there aren’t key regulations that you must follow when collecting, storing and using rainwater. The key regulations you need to follow are:

Water Regulations Advisory Scheme (WRAS)

There are a variety of regulations you should be aware of within the Water Regulations Advisory Scheme. However, the most important regulation pertaining to rainwater harvesting is “Backflow Prevention”. This states that you should have certain preventions in place to stop water from entering the mains water supply. This prevents any non-potable water mixing with potable water.

You can read information from the WRAS here.

Planning Permission

Rainwater harvesting systems rarely need planning permission, however, it would be best to check with your local planning commission to ensure this is the case. There have been previous cases where people have had to dismantle their system due to planning permission issues.

Pipe Marking

All harvested rainwater must be labelled as “non-potable” and not suitable for drinking. This includes the pipework that delivers water around your home and outlets, appliances and valves such as washing machine and toilet taps.

Water Abstraction Licence

If you plan to combine harvested rainwater with water from different sources, then you will most likely need to apply for a water abstraction licence. This includes water sourced from:

  • any watercourse
  • land drainage
  • underground strata
  • gravity intake
  • licensed water abstracted from another source

For more information, find the regulatory position statement on rainwater harvesting here.

How Can I Use Harvested Rainwater?

It’s often the belief that because rainwater falls from the sky that it is perfectly safe for drinking, cooking and personal hygiene. However, that is simply not true. Rainwater is likely to land on the ground or the roof of a home and is, therefore, likely to come into contact with a variety of bacteria, which can cause illness. As such, harvested rainwater should only be used for:

  • Flushing toilets
  • Laundry
  • Washing the car
  • Watering the garden

Harvested rainwater should not be used for:

  • Drinking
  • Cooking
  • Washing dishes
  • Bathing and personal hygiene

Here’s a domestic example of how we suggest you use harvested rainwater.

“A family of four have a house and a 200m2 garden. They use 140 litres of mains water per person each day. Over half of that – 75 litres – goes on washing clothes, flushing toilets, watering the flowers and lawn or hosing down the car. In the course of a year, the family uses about 110,000 litres of drinking water they don’t actually drink.”

With the proper setup, harvested rainwater could help them replace a lot of this waste.

Here is what they save:

Toilets: 24 l x 4 x 365 days = 35,040 litres
Washing machine: 10l x 4 x 365 days = 14,600 litres
Garden: 60 l x 200 m2 = 12,000 litres

The potential savings add up to a remarkable 61,640 litres per year. That’s upwards of £500 saved every year. Good for the environment and good for your pocket.

Free Advice

If you’re struggling for rainwater harvesting advice, ring our dedicated experts on 0800 112 3134 or 0333 577 3134. We’re open Monday to Friday 07:00 - 17:30 and Saturday 08:30 - 12:30.