Predvsem v drugi fazi izvajanja NPVO, predvidoma po letu 2003, pa bo po preliminarnih ocenah potekala intenzivna izgradnja čistilnih naprav za naselja, manjša od 2000 ter naselja od 2000 do 15.000 prebivalcev.
First projections show that building of wastewater treatment plants for settlements with less than 2000 inhabitants and for settlements with between 2000 and 15 000 inhabitants will be carried out in the second phase of the implementation of the NEAP (after 2003).