What happens to the water from your home?
Rain which falls on the roof of your house is collected in the gutter and drainpipes take it down into the sewer. Rain falling on your drive, or other hard areas of your garden flows towards gutters and drains, and then down into the sewer. This water is called rainwater.
Other pipes also take dirty water from the bathroom, washing machine, sinks and kitchen into the same sewer. Dirty water from the toilet is called foul water, the other water (such as from the sink or washing machine) is called grey water – this water is not as dirty as the foul water from the toilet.
We often have combined sewers which means the rainwater, grey water and foul water all go to the same sewer pipe. They get mixed together and all get treated at a sewage works.
Our climate is changing, and we are having more and more heavy rain showers where a lot of rain falls very quickly. Our sewers were built a long time ago and are too small. When it rains heavily the rainwater fills up the sewer, and there is nowhere for the water to go. This causes flooding as the drains are full. It can also cause overflow valves (called combined sewer overflows) to open and a mixture of foul water, greywater and rainwater to go into our rivers, causing pollution.
But what can you do about it?
You can help by building raingardens!
You can help reduce flooding and stop dirty water overflowing into our rivers by slowing down rainwater on its way to the sewer. You can do this using raingardens. You may also hear raingardens being called sustainable drainage or SuDS.
Raingardens use plants, soils and the landscape to hold onto the rainwater and then slowly release it. They also help reduce the amount of water which gets to the sewer. Some water is taken up by the plants, some rainwater finds its way back down into the ground, and some water will evaporate. Raingardens also help clean the water, which may have picked up dirt from the roofs and roads.
Why not just build bigger sewers?
We could build bigger sewers, but this is expensive and may not be the best solution. Rainwater doesn’t need to be sent to a sewage works before it finds its way back to the river. Raingardens also give other benefits to us humans and to wildlife.
Raingardens can provide us with beautiful places to sit, walk through and look at. They provide a space for nature,
giving insects and birds a home and food. The plants which grow in raingardens help improve air quality and water quality. By slowing down the rainwater, and stopping it getting to the sewers so quickly, raingardens help to reduce flooding and protect our rivers.