Stormwater management
See also
Stormwater management
Stormwater is rainwater or meltwater that travels on the surface of the earth, the roofs of buildings, or other similar surfaces, and that is treated either on the plots or lead away from the properties. Also, drainage waters from the foundations of buildings are stormwater. Stormwater forms especially in the spring when snow melts, during heavy rains in the summer and during rainy seasons in the autumn.
Connecting properties to a stormwater drain is regulated by the Act on Water Services. Properties must lead the water from their yard, roof and foundation to a stormwater drainage network in areas where such a network exists. The stormwater drainage network consists of roadside ditches, ditches, retention structures for stormwater, structures for infiltration and purification of stormwater, and stormwater drainage.
If a separate stormwater drainage network does not exist in the area, the properties are not obliged to join a stormwater sewer. In these cases, waters from the buildings’ roof, foundation and drainage can be led to, for example, an infiltration well or a rock pocket built on the property. Leading the property’s stormwater into the sanitary sewer is prohibited under the Act on Water Services.
Guidance and service
- Porvoon vesi (municipal water supply services in Porvoo) serves in matters related to how to connect to a stormwater sewer.
- If your property has no stormwater sewer and you direct the stormwaters to the ditch in the area, please apply for a siting permit for the outlet point and for the pipe in the service Lupapiste.fi.
- The building inspection authority advises on plot-specific stormwater solutions.
- Under certain conditions, the municipal environmental protection authority may, upon application, grant a property exemption from the obligation to connect to the water supply or sewerage system or storm water drainage system of the water utility.
- In public areas such as green spaces and street areas, stormwater treatment is the Urban Infrastructure department’s responsibility.
Please note! The linked web services only exist in Finnish and Swedish.
Stormwater fee
The City of Porvoo will send an invoice to all properties in the development plan area during the autumn of 2025.