If you intend to build a public channel or find yourself nearby, you need a written agreement from your wastewater water supply, so you should consult with the company during the first planning phase of your work. The pipes must be sized for the flow of water to minimize the risk of obstruction and allow air movements. Indications on the size of the pipes are available in the approved document H. A larger roof area increases the amount of surface water. It is best to maintain the additional volume on site to avoid an increasing risk of flooding elsewhere. Rainwater can be kept on site using a moving type or other means to soak it in the soil (called infiltration), or be stored and used for flushing toilets or garden irrigation (known as rainwater harvesting). Approved H provides advice on where soakaways are set up, their size and how they should be built. If you are expanding your land, you need to make sure you know if there are water pipes, public sewers or sewers on your land. It`s a good idea to find out before you start working so that the work goes as smoothly as possible. Surface water drainage carries rainwater (and melted snow and ice) from hard surfaces. The surface system of gutters and rainwater pipes is called roof drainage; underground pipes are called surface water sewers and surface water channels. In order to avoid an increasing risk of flooding elsewhere, it is best to insulate them on permeable soils or to make them from permeable materials. Permeable materials include both porous materials (z.B in the form of grass or reinforced gravel, porous concrete or porous asphalt) and permeable materials (e.g.

B clay bricks or concrete blocks designed for water to pass through joints or cavities). This will not only minimize the impact on the environment, but also avoid the cost of drainage. Additional rainwater pipes may be discharged onto the ground or into new or existing underground pipes. If you decide to drain rainwater pipes to the ground, you need to make sure the water doesn`t damage the foundations (for example. B by encouraging it to spread over a large area) or drain over nearby land (for example.B.