When everyone treats their wastewater, it reduces hygiene issues at the beaches and in residential areas and significantly decreases the risk of groundwater contamination. Wastewater contains bacteria and nutrients dissolved in the water.
Wastewater should always be treated in some manner; it should never be discharged directly into nature or waterways!
Remember that a regular septic tank does not treat the water; it only removes thicker materials from the wastewater!
Wastewater load from a three-person household/year
A few terms that are good to know:
Greywater = wastewater generated from cooking, dishwashing, and laundry (can also be called bdt-water)
Blackwater = wastewater from toilets
A report on the existing wastewater system should be available for each property. If you don't have a report, you should fill one in and keep it on the property. It should be available to show to authorities if needed. Fill out the form Wastewater Report
When you start doing something about your wastewater system, first examine the condition of the existing system and whether the property can be connected to the municipal sewer system.
The measures for the sewage system should have been completed by 10/31/2019. The wastewater must be treated according to the following standards: organic matter (BOD7) at least 90%, total phosphorus (tot-P) at least 85%, and total nitrogen (tot-N) at least 40% compared to the load from untreated wastewater.
Who needs to address their sewage system?
All properties built before 2004 located on a groundwater area or within 100 meters of a watercourse. The distance is determined from the shoreline according to average water levels to the wall of the nearest building where household wastewater is produced.
Others must address the sewage system during reconstruction or renovation that requires a building permit.
If only the sewage system of the property is being repaired, these actions require a permit from the municipal building inspection. When you are renovating or building new structures and applying for a building permit, the sewage system must be addressed at the same time. Documents concerning the sewage system should then be submitted together with the building permit documents.
According to environmental protection laws, a small amount of gray wastewater can be discharged untreated into the ground. For example, if you carry water into a summer cottage or sauna or if the water amount is otherwise small (used only in summer and at most 50 liters/day), a treatment plant is generally not needed. However, if the sauna or cottage is located near the shoreline and the wash water runs more or less directly into the sea, a treatment plant should be in place even for a small amount of water.
If there is a pressurized water line in, you have a shower, dishwasher, or washing machine in the building, the water usage is usually not considered small. Soil treatment is often a good option for treating gray wastewater, but there are also several models of factory-made gray water filters suitable for this purpose.
If there is a well-maintained composting dry toilet (or other equivalent toilet) or a closed tank for toilet water, the treatment of gray wastewater should primarily focus on reducing the organic material load (BOD7). Up to 80-90% of the phosphorus and nitrogen load originates from toilet waste and blackwater.
For measures planned for sewage systems in classified groundwater areas, the ELY Center must be given the opportunity to provide a statement. As a rule, infiltration of wastewater into the ground is prohibited. Wastewater must be transported in sealed pipes and treated in a closed system, with the outlet directed outside the groundwater area.
On properties used for permanent residence, whose holders were born on March 9, 1943, or earlier, there is no need to comply with the legal purification requirement. A condition is that the wastewater does not pose a risk of environmental pollution and that the wastewater treatment system is operational. This age exemption does not apply to new construction.
The deviation from wastewater treatment standards can only be considered in beach and groundwater areas if:
A: The wastewater load on the property can be "remarkably insignificant" OR
B: It is economically unfeasible and technically particularly demanding for the property owner to build the required wastewater system.
The exemption must be applied for at the building and environmental committee and can be granted for five years at a time.
A granted permit expires if the use of the property changes such that the load increases or the property changes ownership or tenancy.