COMMISSION STAFF WORKING DOCUMENT EXECUTIVE SUMMARY OF THE EVALUATION of the Council Directive 91/271/EEC of 21 May 1991, concerning urban waste-water treatment
Date: 2019-12-13
Institutions: Directorate-General for Environment, European Commission
Subjects: application of EU law, environmental monitoring, pollution control measures, urban area, wastewater, water pollutant, water pollution, water protection, water resources, water treatment

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   EUROPEAN COMMISSION  Brussels, 13.12.2019  SWD(2019) 701 final  COMMISSION STAFF WORKING DOCUMENT  EXECUTIVE SUMMARY OF THE EVALUATION of the Council Directive 91/271/EEC of 21 May 1991, concerning urban waste-water treatment     {SEC(2019) 448 final} - {SWD(2019) 700 final}  
 
 
EXECUTIVE SUMMARY  

The Evaluation is based on a comprehensive literature review, including European Court 
of  Auditor  reports,  implementation  reports,  the  European  Environment  Agency’s  work, 
scientific studies and grey literature. Stakeholders were closely involved throughout the 
process:  in  addition  to  a  14-week  public  consultation,  four  expert  workshops  and  a 
stakeholder  conference  were  held.  In  addition,  the  Joint  Research  Centre  modelled  the 
effects of the Directive. In parallel, in cooperation with the OECD, the investment needs 
of  the  EU  water  supply  and  waste  water  sector  and  financing  strategies  for  the  sector 
were analysed.  

The  assessment  of  the  Directive’s  effectiveness  shows  that  it  has  been  successful  in 
reducing loads of the targeted pollutants from urban point sources (domestic/urban waste 
water  and  similar  industrial  pollution).  Loads  of  biochemical  oxygen  demand,  nitrogen 
and  phosphorus  in  treated  waste  water  fell  across  the  EU  by  61%,  32%  and  44% 
respectively between 1990 and 2014. This has clearly improved the quality of EU water 
bodies. The Directive is also the main factor to ensuring that the EU’s bathing water sites 
are  safe  and  through  the  required  treatment  it  reduces  a  number  of  non-targeted 
chemicals.  Despite  overall  high  levels  of  compliance  at  the  time  of  the  Evaluation,  the 
implementation  process  was significantly delayed in  some Member States, while a  few 
Member States are still lagging behind. As shown in Figure 1, the remaining loads from 
urban sources come largely from non-compliant agglomerations.  

The  main  barriers  to  implementation  include  Member  States  not  prioritising  the 
necessary investments in time to meet the deadlines, with problems often stemming from 
governance  arrangements  at  central,  regional  and  local  level  and,  in  particular,  lack  of 
resources  and  administrative  capacity.  To  steer  the  implementation,  the  Commission 
provides support through funding, research and innovation programmes, and compliance 
infringement  procedures,  whenever 
promotion  activities,  whilst  also  conducting 
appropriate.  The  implementation  of  the  Directive  requires  substantial  and  continuous 
investments  in  infrastructure.  Its  implementation  is  strongly  supported  by  EU  cohesion 
policy  (EUR  38.8  billion  for  the  waste  water  sector  since  2000).  Preliminary  OECD 
estimates show that an additional EUR 253 billion has to be spent in the EU until 2030 to 
maintain  or  achieve  full  compliance.  At  the  same  time,  Member  States  do  not  invest 
sufficiently  in  the  renewal  of  infrastructure.  To  finance  implementation,  most  Member 
States use a mix of water tariffs and public budget  transfers. Water management  in  the 
EU  is  typically  based  on  public  and  delegated  private  management  models,  with  the 
water infrastructure generally being owned by public authorities. Whereas households are 
usually  charged  through  the  water  bill,  full  cost  recovery  has  not  been  achieved  in  the 
majority  of  the  Member  States.  Under  Article  9  of  the  WFD  it  is  acceptable  that 
households are supported through social schemes or subsidies. Water  affordability can 
be an issue, which can be addressed nationally or locally by establishing social tariffs, or 
through other specific support. 

One  of  the  key  reasons  for  the  Directive’s  effectiveness  is  its  overall  clarity  and  the 
simplicity of its requirements allowing for straightforward enforcement. Nevertheless, 
it  has  not  optimally  addressed  some  important  pressures  in  relation  to  waste  water  and 
that lead to remaining loads that could be avoided (see also Figure 1):  

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1.  Storm water overflows, a sizeable remaining source of loads, are referred to only in 
a footnote in the Directive. The Court of Justice of the European Union has pointed 
out the need to develop guidance in this area. Urban runoff, which is only covered 
by  the  Directive  in  connection  with  combined  sewage,  is  an  increasingly  important 
source  of  pollution,  and  may  contain  heavy  metals,  plastics  and  microplastics.  The 
loads from these two sources are increasing due to, among others, heavy precipitation 
becoming more frequent and intense under the changing climate.  

2.  Other remaining sources of loads result from  the use of potentially mal-functioning 
individual  or  other  appropriate  systems.  The  Directive  allows  the  use  of  these 
systems  where  a  collection  systems  comes  at  disproportionate  costs,  and  as  long  as 
these individual systems achieve the same level of environmental protection. But it is 
not clear on the extent to which this provision can be applied and how the functioning 
of these systems should be monitored.  

3.  Those small agglomerations or non-connected dwellings not completely covered by 
the  Directive  constitute  a  significant  pressure  on  11%  of  the  EU’s  surface  water 
bodies.  

Figure 1 Remaining loads that can be avoided (SD=agglomerations <2 000 p.e., CSO=combined 
sewer overflows, IAS=individual or other appropriate systems); As comparison, the total urban 
waste water generated is about 612 mio p.e. Source: Pistocchi et al., 2019. 

Another  problem  is  that  Member  States  seem  to  apply  the  criteria  for  identifying 
‘sensitive  areas’  differently,  especially  in  the  context  of  eutrophication  and  nutrient 
management. Although the Court intervened and established a definition, the assessment 
of  2014  reporting  shows  that  Member  States  still  have  different  approaches  to 
designating  these  areas.  Tackling  these  remaining  sources  of  pollution  and  clarifying 
some  provisions  would  enable  benefits  to  be  maximised,  building  on  the  already 
significant achievements in waste water collection and treatment. 

In  view  of  technological  progress,  some  of  the  Directive’s  provisions  on  information 
gathering  and  dissemination  are  less  effective  today  than  when  it  was  adopted. 
Monitoring  under  the  Directive  has  proven  effective  to  demonstrate  compliance. 
However,  over  time,  research  and  innovation  outcomes  enable  advances  in  monitoring 
methods allowing more efficient and accurate monitoring of both existing and emerging 
pollutants.  A  number  of  Member  States  –  depending  on  local  conditions  –  set  stricter 
emission  limit  values  than  those  minimum  requirements  set  in  the  Directive.  Further 
research is required to establish whether the provisions on e.g. the frequency of sampling 

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provisions at waste water treatment plants to demonstrate compliance under the Directive 
are fit for purpose.  

Although the reporting requirement has improved knowledge of waste water collection 
and treatment in the EU, some of these provisions are now outdated, compared to what 
might  be  achieved  by  using  digital  technology.  The  Directive  requires  that  Member 
States provide situation reports to keep the public informed. This has led to divergences 
in practice across the EU, and it is not always the case that relevant information is always 
made readily available to the public in a clearly comprehensible form. Since waste water 
collection  and  treatment  account  for  about  60%  of  the  water  price,  and  the  public 
consultation  shows  that  the  public  are  generally  interested  in  both  collection  and 
treatment  costs  as  well  as  investments,  providing  this  type  of  information  would  be 
important. 

In this Evaluation, the use of well-established cost functions enabled comparably robust 
assessments  to  be  made  of  the  implementation  costs.  Assessing  benefits  was  more 
complex, as only some of them can be quantified and monetised. The efficiency analysis 
shows  that  even  with  very  conservative  assessments  of  benefits,  the  benefits  outweigh 
the costs. Total EU capital and operation costs are estimated at EUR 18 billion p.a. in the 
EU, while (the quantifiable part of) benefits is estimated to amount to EUR 27.6 billion 
p.a  at  current  implementation  levels.  Through  its  provisions  on  individual  and  other 
appropriate  systems,  the  UWWTD  includes  a  flexibility  mechanism  that  allows  taking 
into account  local  conditions  and avoid  cost  ineffective investments.  Whereas costs are 
incurred  by  users  (e.g.  households,  some  industries),  benefits  are  of  the  advantage  not 
just  of  users,  but  of  a  variety  of  stakeholders  downstream,  which  might  be  in  another 
region or Member State. Administrative costs are negligible compared to the capital and 
operational  costs.  In  particular,  the  administrative  burden  linked  to  the  monitoring  and 
reporting  requirements  appears  to  be  between  low  and  moderate.  Most  of  the  costs  are 
borne by Member States, their competent local authorities and the Commission.  

The  assessment  of  coherence  shows  that  the  Directive  is  internally  coherent  overall. 
The  UWWTD  works  overall  in  synergy  with  other  EU  water  law  and  contributes 
strongly  to  achieving  the  objectives  of  the  Water  Framework  Directive,  the  Bathing 
Water  Directive  and  the  Drinking  Water  Directive.  There  are  some  limited  overlaps  in 
terms  of  what  activities  are  covered  by  the  UWWTD  compared  to  the  Industrial 
Emissions  Directive.  In  general,  there  are  also  no  issues  of  coherence  with  newer  EU 
polices;  however,  there  may  be  some  scope  for  improving  the  coherence  of  the 
UWWTD and climate and energy policies, such as the energy efficiency directive.  

The  analysis  of  relevance  and  effectiveness  shows  the  need  for  continued  intervention 
not least because inappropriately treated or untreated urban waste water is still one of the 
main  reasons  why  EU  waters  fail  to  achieve  at  least  good  status  under  the  Water 
Framework  Directive.  Moreover,  the  scientific  community,  policy  makers  and  general 
public  see  the  growing  evidence  of  contaminants  of  emerging  concern,  including 
pharmaceuticals  and  microplastics,  in  water  bodies,  as  an  increasingly  important  issue. 
The  need  for  action  on  pharmaceuticals  and  microplastics  was  also  noted  in  the 
Commission’s  2019  Strategic  approach  to  pharmaceuticals  in  the  environment  and  its 
2018 Plastics strategy. Plants covered by the UWWTD also receive significant amounts 
of  industrial  waste  waters  containing  a  range  of  chemical  pollutants.  Overall,  the 
treatment  required  under  the  UWWTD  reduces  such  pollutants  of  waste  water  to  some 
extent,  but  does  not  target  them  directly.  Some  countries  already  have  additional 
treatment  in  place,  for  instance  Switzerland  requires  its  priority  plants  to  tackle 
micropollutants by 2040.  

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As  regards  circular  economy  potentials,  the  UWWTD  contains  limited  provisions  on 
waste  water  and  sludge  reuse  or  recovery  of  valuable  components.  These  have  never 
been strictly enforced, partly due to the lack of strong harmonised standards at EU level 
and  the  potential  risks  to  human  health.  The  adoption  of  the  Commission  proposal  on 
water  reuse  will  create  further  incentives  to  reuse  water.  Sludge  reuse  in  agriculture  is 
governed  by  the  1989  Sewage  Sludge  Directive,  but  over  the  past  decades,  Member 
States have either set stricter requirements than those imposed by the Directive or have 
simply  banned  sludge  use  in  agriculture  on  public  health  grounds.  The  removal  of 
pollutants from waste water can lead to polluted sludge and there is a risk of spreading 
these  pollutants  if  contaminated  sludge  is  used  for  agricultural  purposes.  Control  at 
source  of  targeted  pollutants  would  reduce  treatment  requirements.  With  regards  to 
energy, the annual energy consumption of the waste water treatment sector is estimated 
at 0.8 % of all energy consumed in the EU. This is contrasted by a number of WWTPs in 
the  EU  being  re-designed  to  be  energy  producers.  The  UWWTD  and  other  EU  water 
legislation have also created a strong basis for innovation. At the time of the Evaluation, 
eight  out  of  the  top  15  worldwide  water  businesses  were  based  in  the  EU,  showing 
clearly the global business leadership of this sector. 

Lastly,  the  EU  added  value  assessment,  which  included  considering  whether  the 
UWWTD  complies  with  the  subsidiarity  principle,  shows  wide  recognition  among 
stakeholders  that  the  Directive  is  still  needed,  and  that  withdrawing  it  would  have 
negative  impacts.  The  Directive  supports  the  protection  of  some  60%  of  EU 
transboundary water basins from the adverse effects of waste water discharges.  

In the future, more attention should be given to both existing and emerging sources of 
pollutants  with  regards  to  environmental  and  human  health  perspectives,  and,  from  the 
socio-economic  perspective,  to both  sustainable investment strategies  and  affordability. 
To  achieve  this  in  a  global  and  climate  change  context,  continuous  research  and 
innovation  efforts  and  investments  are  needed,  in  particular  to  develop  advanced  and 
resilient  treatment  and  monitoring  solutions,  to  enable  cost-effective  management  of 
micropollutants  and  to  better  integrate  circular  systems  for  water/sludge  reuse  and 
recovery of components. 

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