Septic tank and cesspool sludge

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Emptying sludge tanks

Waste management of septic tank and cesspool sludge from residential buildings is regulated by waste management regulations.

Regular sludge emptying is essential to keep wastewater system working properly and to prevent risks to the environment and health.

Sludge tanks must be emptied as follows:

  • septic tanks and small treatment plants containing black wastewater (i.e. toilet water): as needed, at least once a year.
     
  • septic tanks and similar tanks containing only grey wastewater (i.e. washing water): as needed, at least every three years.
     
  • Cesspools: as needed, with regular monitoring of filling.

How to order emptying of sludge tanks

In the Regional waste management authority’s operation area (excluding Nokia), residential sludge tank emptying must be ordered from Pirkanmaan Jätehuolto. Learn more:

In Nokia, residential sludge emptying must be arranged through contractors approved in the ELY Centre’s waste management register. You can confirm a contractor’s approval by asking the contractor or by checking the Waste management compass -online service.

Self-treatment of septic tank and cesspool sludge

In exceptional cases, self-treatment of septic tank and cesspool sludge is possible. This requires proper hygienisation of the sludge and prior notification to the waste management authority.

When sludge is treated independently, the emptying intervals specified in the waste management regulations must be followed.

Spreading treated sludge on field

Treated sludge from septic tank and cesspool may be used as fertiliser on your own field or on a field under your control.

Before spreading, the sludge must be treated by lime stabilisation or another method approved by the Finnish Food Authority or the environmental protection authority. 

The person handling the sludge must have enough land suitable for agricultural or similar use where spreading is permitted.

Small-scale joint treatment of sludge

  • Small-scale joint treatment of septic tank and cesspool sludge is allowed under certain conditions. Sludge may be treated on a neighbouring or nearby property.
  • In addition to own property, the handler may treat sludge from up to five (5) nearby properties.
  • The same requirements for field spreading apply to jointly treated sludge as to self-treated sludge.

Composting of sludge

In certain cases, sludge can be treated by composting on the property.

Sludge from a small wastewater treatment plant may be composted, if the sludge is instructed to compost in the manufacturer's maintenance manual. If the sludge contains faecal matter, the following requirements must be met:

  • The composter (or dry toilet unit) is designed for its purpose and well ventilated.
  • The composter is protected against against pests, and leachate must not enter the soil.
  • The composting period for faecal waste is at least one year.

Small amounts of greywater sludge may be composted in a composter, a wooden or metal frame or a pile.

Notification of self-treatment of sludge

Self-treatment of septic tank and cesspool sludge must be notified to the waste management authority before treatment begins.

For joint self-treatment, the notification must be made in the name of the person responsible for the treatment. The notification must include details of all properties covered by it.

Notifications are forwarded to the ELY Centre’s agricultural unit and to the municipal environmental protection authorities, who act as supervisory authorities. The supervising authority may prohibit the self-treatment of sludge if it is not appropriate.

You can submit a notification via the waste management authority's e-service (in Finnish). You can log in using your banking credentials or a mobile certificate.

You can also submit a notification using the PDF form.

Frequently asked questions about sludge emptying

Updated 7.1.2026