Water Butts V Flash Floods

In recent days there has been flash floods in the London area and serious flooding in Germany and Belgium. Water butts if widely used in a village or suburb can slow water going into drains considerably, and could prevent localised flooding. For example, imagine if a town of 10,000 homes suffered from flash floods, and each home then had a 400 litre double kit water butt installed. The next time there is heavy rain, a total of 4 million litres of water instead of rushing into drains then overflowing onto roads, would go into the water butts. This in total would be the equivalent to two Olympic size swimming pools of water, being saved from overwhelming the sewage and drain network. One simple solution to help deal with a terrible problem.