Diffuse Pollution, Degraded Waters

Emerging Policy Solutions

In series:OECD Studies on Waterview more titles

Published on March 22, 2017

After decades of regulation and investment to reduce point source water pollution, OECD countries still face water quality challenges (e.g. eutrophication) from diffuse agricultural and urban sources of pollution, that is disperse pollution from surface runoff, soil filtration and atmospheric deposition. The relative lack of progress reflects the complexities of controlling multiple pollutants from multiple sources, their high spatial and temporal variability, associated transactions costs, and limited political acceptability of regulatory measures. This report outlines the water quality challenges facing OECD countries today, presents a range of policy instruments and innovative case studies of diffuse pollution control, and concludes with an integrated policy framework to tackle diffuse water pollution. An optimal approach will likely entail a mix of policy interventions reflecting the basic OECD principles of water quality management – pollution prevention, treatment at source, the polluter pays and beneficiary pays principles, equity, and policy coherence.


Foreword and Acknowledgements
Acronyms and Abbreviations
Executive summary
The Water Quality Challenge
An overview of the main water pollutants in OECD countries
Economic costs and policy approaches to control diffuse source water pollution
Emerging policy instruments for the control of diffuse source water pollution
A policy framework for diffuse source water pollution management
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OECD countries have struggled to adequately address diffuse water pollution. It is much easier to regulate large, point source industrial and municipal polluters than engage with a large number of farmers and other land-users where variable factors like climate, soil and politics come into play. But the cumulative effects of diffuse water pollution can be devastating for human well-being and ecosystem health. Ultimately, they can undermine sustainable economic growth. Many countries are trying innovative policy responses with some measure of success. However, these approaches need to be replicated, adapted and massively scaled-up if they are to have an effect.”

Simon Upton – OECD Environment Director


COUNTRY case studies

Full case studies submitted by member countries and international organisations for this project are presented below. Selected case studies have been included in this report. Several more of the case studies will inform the forthcoming OECD work on contaminants of emerging concern in surface water.

Water Quality and Agriculture

England England Korea, Republic_small Korea New Zealand_small New Zealand United States_small United States  

Urban Water Quality Management

Ireland_small Ireland Israel Netherlands_small The Netherlands OECD countries Baltic region

Financing Water Quality and Investment Infrastructure

France_small France United Kingdom_smallUnited Kingdom United States_small United States    

Water Quality Governance

England England Hungary_smallHungary New Zealand_small New Zealand    

Information Systems

Israel New Zealand_smallNew Zealand    


Policy Highlights


Infographic - What are the impacts of water pollution?



  • 6 April 2017 (13:00 CET) - OECD Green Talks Live on Degraded Waters: Emerging policy solutions to tackle diffuse pollution - Hannah Leckie and Xavier Leflaive of the OECD Environment Directorate discussed emerging solutions in OECD countries, that can guide the design and implementation of policies to control diffuse water pollution.

  • 22 March 2017 - OECD participation in the World Water Day 2017 Webinar on wastewater organised by International Water Resources Association (IWRA). Details on IWRA press release.

Global distribution of water pollution hazard, 2000

 Figure 1.1. Global distribution of water pollution hazard, 2000

Note: Map includes the effects of nutrient and pesticide loading, mercury deposition, salinisation, acidification, and sediment and organic loading.
Source: Sadoff et al. (2015); based on data from Vörösmarty et al. (2010).