Stormwater

Property owners are responsible for stormwater management on their own property. The Stormwater treatment on properties guide provides information on how property owners can reduce, detain and treat stormwater.

Stormwater management is important for both the condition of the property and the state of the environment. Well-managed stormwater does not pose a risk to the property, and collecting stormwater for irrigation purposes saves money. Stormwater management reduces the pollution of water bodies and can promote the biodiversity of yard areas.

The City of Espoo has introduced a municipal stormwater fee, effective from 2026.

The fee applies to all properties located within the city’s stormwater system area, i.e. in the areas covered by detailed plans, excluding areas with a detailed shore plan. A stormwater fee is charged to cover the municipality’s costs arising from the stormwater system. The amount of the fee depends on the use of the buildings located on the property and the size of the property. The fee is charged annually. The amount of the fee is determined in accordance with the fee schedule approved by the City Board(external link, opens in a new window).

The stormwater fee applies to developed properties and leased areas, i.e. properties and leased areas that have buildings on them. The stormwater fee also applies to areas that are designated in the detailed plan as LP or LH areas, even if there is no building on the property.

There are two stormwater-related fees in Espoo: the municipal stormwater fee and the stormwater sewerage fee charged by the Helsinki Region Environmental Services Authority (HSY). The municipal stormwater system includes, for example, stormwater management in public areas, stormwater detention solutions, infiltration basins, and ditches. The estimated costs of planning, constructing and maintaining the system are about EUR 7 million per year, of which the stormwater fees cover about one third.

The unit price of the City of Espoo’s stormwater fee (X) is EUR 30.

The maximum amount of the stormwater fee is EUR 5,000.

The table below shows the stormwater fees by fee category and property area. The fees in the table do not exceed the maximum stormwater fee that can be charged. The amount that would apply without the maximum fee is shown in brackets. The fees shown in the table do not take into account any property-specific reductions that may be granted. The property categories that may be eligible for a reduction in their stormwater fee are highlighted is bolded.

Who has to pay the municipal stormwater fee?

The owner or holder of the property is responsible for paying the stormwater fee. The stormwater invoice is sent to the tenant of a property leased from the municipality when the tenant’s details are recorded in the municipal property register. If a property has several owners, the invoice is sent to one of the owners, who is responsible for making the payment on behalf of all the owners.

Do I have to pay the stormwater fee even if I was not aware that my property is connected to the municipal stormwater system?

The municipality has the right to charge a stormwater fee to cover the costs of planning, implementing, using and maintaining the municipal stormwater system. The fee, based on public law, is directly enforceable and does not require an agreement with the city. The fee applies to properties located within the city’s stormwater system area and does not depend on the extent to which the detailed plan has been implemented.

How is the stormwater fee invoiced?

The fee is invoiced annually and must be paid by the due date specified on the invoice. The invoice is delivered either electronically as an e-invoice, via Suomi.fi Messages, or as a paper invoice by post.

If the fee remains unpaid despite a payment reminder, it may be collected through enforcement without a separate judgement or decision.

Can I request a review of my stormwater fee if there is an error in my invoice?

The person liable for payment may submit an objection in accordance with the instructions provided with the invoice within 14 days of receiving the invoice. The city will make a decision on the objection and send the person liable for payment a new invoice if the amount of the fee is changed.

The municipality may correct errors related to the property register or the determination of the stormwater fee on its own initiative. Corrections are made by municipal experts as part of the process of determining the stormwater fee. The property’s fee category can be corrected to reflect its actual main use if the building classification or property area results in a clearly unreasonable fee. The area used in calculating the stormwater fee may be corrected to correspond to the area of the property covered by the detailed plan.

Can the fee be reduced?

A property with an area of more than 20,000 m² may be eligible for a reduction in the stormwater fee if it meets the requirements concerning the permeability of the property’s surface. The municipality assesses properties’ eligibility for a reduction and automatically grants the reduction to eligible properties. If a reduction has not been granted automatically and the property owner or holder considers the property eligible, the reduction must be applied for in writing (by submitting an objection; see above). The reduction also applies to properties whose stormwater fee is set at the maximum fee. In such cases, the reduction is calculated from the maximum fee.

A reduction granted to a property remains valid until further notice. The city has the right to withdraw the reduction if the circumstances of the property change.

What are the conditions for receiving a reduction? 

The stormwater fee may be reduced for properties with a total area of more than 20,000 m² that fall into fee categories 2, 3 or 4. The condition is that at least 40% of the property’s total area consists of permeable ground surface.

The proportion of permeable surface is assessed using the most recent land cover dataset produced by the Helsinki Region Environmental Services Authority (HSY), or equivalent data. The natural land cover types classified as permeable or equivalent to permeable in the HSY dataset are: other low vegetation, trees 2–10 m, trees 10–15 m, trees 15–20 m, trees >20 m, bare rock, and water.

The reduction in the stormwater fee granted on the basis of surface permeability is 20%. The reduction coefficient (V) used in calculating the fee is therefore 1−0.2 = 0.8.

The property owner is responsible for the treatment of stormwater on their own property and maintains e.g. culverts, open ditches, boundary ditches, stormwater pipes and other stormwater management structures.

Open ditches and stormwater pipes or culverts located on the property are part of the property’s maintenance. Likewise, the property’s gutters, drains, leach pits, retention ponds, stormwater pumping stations and other stormwater management structures.

See more about the property’s stormwater management in HSY's video (external link, opens in a new window)(in Finnish).

The maintenance of a ditch that runs along the border of two or more properties belongs to all the properties that benefit from the ditch. Boundary ditches should be kept open and free of debris, even if most of the buildings are connected to the stormwater drain. A well-kept ditch prevents flooding by directing water forward, for example during heavy rain, when the stormwater drain cannot take more water.

Culverts of access ramps

The culvert pipe of the property’s driveway must be maintained by the property, as the driveway serves the property’s needs. See more about property maintenance obligations in the video(external link, opens in a new window) (in Finnish).

You should pay attention to snow management on your own property. Snow must be collected and stored on your own property, for example, in the places shown in the building permit. Snow is not collected on a neighbour’s or city’s land. If necessary, snow must be transported to a snow disposal site. It is the property’s own responsibility to manage the meltwater from the snow collected from its own yard, and the meltwater must not cause harm to the neighbours. The same duties apply to the leaseholder of a plot.

When building a new home or moving into a new home, the framework created by the surrounding terrain for stormwater management must be taken into account. If the property is located below a slope or at the lowest point of its surroundings, the natural flow direction of the water is towards the property. In these areas, it is particularly important to take care of sufficiently efficient drainage of your own plot. Even if the buildings in the area are connected to the stormwater drain, natural runoff always occurs in the environment when it rains or ice or snow melts on the grass, wooded area or rock. It is not necessary or even possible to control all the water on the plot. The need for management focuses on water that accumulates on built-up, impermeable surfaces, i.e. stormwater.

The city builds public stormwater systems so that stormwater can be managed harmlessly. According to the legislation, connection is mandatory, so that stormwater does not cause harm to others and the costs of construction can be covered. You can get an exemption from connecting under certain conditions.

The property’s stormwater must be treated in the following order:

1. The stormwater must be steered to a general stormwater drain if the property is located in the area of stormwater drainage (typically when a stormwater drain runs along the street) or be exempted from this obligation. Below is more information about application.

2. Stormwater must be absorbed into the ground on the property.

3.  Stormwater must be steered to the city’s other stormwater system (e.g. street ditches, park ditches), in which case consent must be applied for from the city.

Provision is made for stormwater management through urban planning. To support the work with planning, regional stormwater surveys and plans for stormwater management are prepared. The local master plan and partial master plan clarify the needs of stormwater  management by catchment area and evaluate the effects of construction on surface water and groundwater. Sustainable stormwater management can be required in the land use plan, for example with regulations regarding delay or stormwater quality. As an example, the basic plan regulation regarding stormwater management used in city plan sites:

"Stormwater coming from impermeable surfaces must be delayed in the area in such a way that the dimensioned volume of delay ponds, basins or tanks must be one cubic meter for every hundred square meters of impermeable surface. The delay ponds must be emptied within 12–24 hours of being filled, and a controlled overflow must be planned for them."

At their best, stormwater structures enliven the surrounding environment and increase the diversity of urban nature. For example, rain gardens makes the neighbourhood more beautiful. Flood meadows provide new habitats for many plant and animal species whose natural habitats have become scarce. Urban planning guides and encourages the implementation of green roofs. Green roofs are useful both in managing stormwater and in improving climate resistance and the comfort of the city.

HSY (Helsinki Region Environmental Services joint municipality authority) is responsible for the stormwater trunk lines, i.e. the long pipelines that move stormwater forward. HSY’s network carries drainage water from streets and stormwater from properties. HSY maintenance cleans pipes and wells as needed. More information is available from HSY’s own customer service: www.hsy.fi/hsy/asiakaspalvelu/(external link, opens in a new window).

The infrastructure services of the City of Espoo is responsible for stormwater pumping stations, open ditches located in the public area, stormwater basins in green areas and short culvert sections of open ditches. The maintenance of infrastructure services cleans grating wells further away from the trunk line, which collect stormwater from streets and other public areas. in particular, sand and leaves collect in wells as well. Also branches, garbage, vegetation and sediment collect in open systems (ditches and basins), which must be removed from time to time.

Stormwater is taken into account in all the city’s street and park construction projects. As a rule, wells and pipes are built in new street areas; ditches, depressions and basins in the park. In the renovation project of the old street, open ditches are often abandoned and pipes that save street space are built. In the pipeline, stormwater moves more reliably and efficiently from the plots and the bends of the streets. Parks are the best place to build delay and flooding space in public areas. In a pipe, the water goes quickly as it is, but in open systems it lingers, soaks into the ground and is filtered cleaner.

Street and park areas in the planning stage: www.espoo.fi/en/street-plans. In addition, there is a home street portal where you can check the planning and construction schedule of the streets in your area: https://kotikatu.espoo.fi/(external link, opens in a new window)

Properties bordering the street area to be built will receive a notice and an invitation to both comment on the planning phase and the construction start survey.

The City of Espoo has prepared a stormwater programme to improve water quality and reduce stormwater floods. Espoo’s stormwater programme 2025-2034(external link, opens in a new window) (in Finnish) contains a description of Espoo’s geographical characteristics, stormwater actors, the current situation of stormwater management and management goals. The most important actions to achieve the goals of the stormwater programme are the improvement and development of cooperation and operating methods related to stormwater, increasing stormwater expertise and awareness, and even better stormwater information management. The aim of the stormwater programme is to bind actors who affect stormwater to adhere to common principles.

You can find answers to questions about stormwater on the Frequently Asked Questions About Water page.