Public sewage system, 2021

Slightly more municipal waste water generated

In 2021, 232.7 million m3 of waste water was brought into the public sewage system in Slovenia. Waste water was of different sources: 0.2% from agriculture, 6.1% from industry, 8.0% from other activities, 31.1% from households and 54.6% was other waste water (such as rainwater, run-off rain water, etc.).

Households generated 72.4 million m3 of municipal waste water, 17.5% more than in the previous year.

Two thirds of waste water treated before release 

160.7 million m3 of waste water was treated before release from the public sewage system into the environment. The largest quantity of waste water was treated with tertiary treatment (49.0%) and the smallest quantity (2.0%) with primary treatment.

The share of treated waste water was the largest in the Pomurska statistical region (100%), followed by Notransko-kraška (98%), Zasavska and Jugovzhodna Slovenija (94%). In all these regions the largest quantity of waste water was treated with tertiary treatment, namely in the Pomurska statistical region 65.0%, in the Notranjsko-kraška statistical region 84.0%, in the Zasavska statistical region 94.0% and in Jugovzhodna Slovenija 75%. The largest quantity of waste water was treated with secondary treatment in the Spodanjeposavska statistical region (49.0%), followed by the Osrednjeslovenska statistical region (34.0%).

The remaining 71.9 million m3 or 31.0% of waste water remained untreated. Almost 98.3% of untreated waste water was discharged into surface water and the remaining 1.7% into ground water and on the coast. On the other hand, treated waste water was discharged in almost equal shares: 96.2% into surface water, about 1.5% on the coast and just over 2.3% into ground water.

Less drainage waste water (rainwater and run-off rain water) 

Rainwater and run-off rain water represented 54.6% of waste water. Compared to 2020, the quantity went down by 3.8%. Almost 126.9 million m3 of waste water ran off from roofs and hardened paved areas into the public sewage (or the soil).

Detailed data are available in the SiStat Database.