Tillsyn av små avlopp : Bättre stämma i bäcken än i ån

Water is crucial for all life on this planet. Despite this much of our aquatic environments have become affected by pollution and nutrient-loading. One large contributor to the problem is privately owned sewers, also called on-site sewage systems. Currently there are approximately 691 000 on-site sewage systems in Sweden, which carry the infamous distinction of representing one of the largest point sources of phosphorus and nitrogen. Furthermore roughly 180 000 of these sewers are by legal definitions unlawful, because of substandard wastewater treatment. The purpose of this study was to investigate how Sweden’s 290 municipalities conduct their supervision towards privately owned sewages and what inventory and administration rates they have. A hypothesis was there should be a correlation between municipalities’ inventory and administration rates. The study was conducted by a web-survey sent out to all municipal environmental and health offices. The results show a majority of the municipalities have an inventory ongoing, or have already conducted one. Administration and inventory rates at which on-site sewage systems are being controlled are rather low, numbering 3.1 respectively 3.6 percentages per year. Surprisingly there was also a low correlation between the inventory and administration rates, with an r-value of only 0.29 (r2 ≈ 0.085). Overall, the results indicate a need to increase oversight of inadequate and non-regulatory on-site sewage systems if we are to meet our national environmental goals and our global sustainable development goals