Buckinghamshire Partnerships

Reduce rainwater runoff

Reduce rainwater runoff

Reducing rainwater runoff from your property can really help in the fight against flooding.  It’s easy to do and brings many benefits. This page contains information on how to: cut your water bill, attract wildlife to your garden and reduce your water use while doing your bit to reduce flooding in Chesham.


Although weather conditions are often to blame for flooding, we shouldn’t forget that our lifestyles and activities also negatively contribute to the problem. You may not think your paved front garden or driveway has much of an impact, but it all adds up, much in the same way that our personal choices about transport, landfill waste and energy use do. 

The FloodSmart project has created a leaflet outlining some of the things you can do to reduce the amount of rain that runs off your property. Below are some links to useful information about the ideas contained in the leaflet.

Collecting rainwater: water butts and other ideas

Water butts are the simplest way to collect rainwater: connect one to a downpipe to collect the rain that falls on the roof of your house, garage or shed. A tap at the bottom allows you to fill up a watering can or connect a hose. Water butts are available in different sizes depending on the space you have available and the use you intend to make of it. Most DIY and home improvement stores sell water butts online or in store; also look on ebay for used ones. You can also buy water butts on Affinity Water’s Save Water page, where discounts can be available for customers.

Water butts are mainly used to water plants, wash cars or other simple uses that don’t require clean drinking water. More complex systems for collecting rainwater exist: they can store rainwater in underground tanks and filter it for use in flushing toilets or washing clothes. Generally in the UK these systems are not designed to provide drinking water, though this technology does exist. These systems are easier to integrate into new buildings, though they can also be retrofitted.

Read more from the Environment Agency, Waterwise, the Centre for Alternative Technology (CAT), the YouGen website, the Royal Institute of Building Architects (RIBA), and some tips from this BBC article. Anglian Water has produced a useful summary of reuse systems, and the UK Rainwater Harvesting Association’s website contains some useful information, including this guide about the different systems and considerations for each.

Creating a raingarden

Download this useful guide on how to create a raingarden: it includes information on how to plan, build and plant a raingarden.

The Wildfowl & Wetlands Trust has produced a leaflet about raingardens which you can download here; they’ve also created several videos on the subject: watch them here, here and here.

Read this BBC article and this article from The Ecologist summarising the benefits of raingardens. Here are some pictures of raingardens in an urban setting in London.

Growing a green roof

Visit the Green Roof Centre’s website for all manner of information, including this guide on DIY installation, these examples of DIY installations in the UK, this pocket guide on everything from types and costs to maintenance.

The Green Roof Guide’s website is a one-stop shop for all information about green roofs, including benefits, construction and maintenance. You can also download the whole guide as a pdf here.

Here is an example of a smaller green roof, created on top of a shed. The Wildfowl & Wetlands Trust has made a short video about green roofs you can watch here.

Reducing water-resistant paving

The Royal Horticultural Society’s website includes information on how to choose, design and build a permeable (porous) surface. Read their useful brochure on permeable paving and its connection to flooding.

Visit the Planning Portal’s page on paving of front gardens for information on types of permeable surfaces. Remember, you’ll need planning permission if you want to pave over (using impermeable surfacing) more than 5m2 of your front garden. Read this guidance from the Department for Communities and Local Government for more information.

This website is specific to London but has a list of 43 reasons not to use impermeable paving.

Here's an example of how FloodSmart helped reduce rain water runoff for a Chesham resident.  

Tofree case study

David Tolfree and his Fiancée live in Lowndes Avenue, Chesham.  Lowndes Avenue is on a hill which leads down to an area prone to flooding. Their drive is on a slope so when it rained, the water ran off and into the road. The drive was made of an uneven impermeable surface (concrete), meaning there was nowhere for the water to drain to. The impact of this was the build up of water and mud on the drive.

David applied for the FloodSmart runoff reduction grant after seeing it advertised and was match-funded to replace the driveway with gravel over a stabilising base (made of hexagonal cellular plastic).  Local company Heritage Landscapes was contracted to do the work and dug out the solid concrete to about 150mm to put the material down.  The new permeable driveway has completely stopped runoff and has allowed the water to drain away over the entire drive surface. Gravel also creates very low maintenance, with base matting preventing any weeds growing through. The further benefit to having gravel is the noise it makes when someone is approaching the house. This is ideal for security.   

Says, David, “We applied on the off-chance, not really expecting to receive the grant, so we were delighted when we heard we’d been successful. It all happened very quickly and the contractor took less than a week to complete the job. 

“Previously, rainwater ran off down the road adding further to Chesham’s surface water problem or sat in great puddles, so we were always traipsing mud or water into the house. We’re really pleased with the result; we feel we’ve helped the community and the environment and we’ve got a driveway which is lovely and has much improved the frontage of the house.”

The Tolfree’s also got a water butt under the grant scheme. “As a result of FloodSmart, we’re much more aware of surface water runoff and where you can save water,” adds David.

In 2014, FloodSmart offered a match-funding grant for the installation of runoff reduction measures such as water butts, permeable paving and tree planting. This grant was set up in an effort to help address surface water runoff and flooding problems in the town.

Other ideas and  links

Affinity Water’s website contains useful tips for saving water around the home and garden.

If you can show that all of the rain water falling on your property does not go into the main drainage system, you can apply for a reduction on your waste water standing charges. For more information, see here.