Nature for Water and Sanitation

Nature-Based Solutions

What exactly are nature-based solutions? The International Union for Conservation of Nature, defines NBS as actions to protect, sustainably manage and restore natural or modified ecosystems, which address societal challenges (e.g. climate change, food and water security or natural disasters) effectively and adaptively, while simultaneously providing human well-being and biodiversity benefits”.

A constructed wetland integrated into the public landscape at Kunshan Culture Plaza Wetland, in China. Read Kunshan’s overarching strategy to develop into a Sponge City.


Investment in nature-based solutions is increasingly seen as a way to address local water challenges in both urban and rural settings such as floods, shortages in supplies, more sustainable usage of the resources or degradation of water quality. A range of methods are increasingly being applied at local levels to restore environmental, social and economic benefits provided by ecosystems. These include restoration of watersheds through reforestation, reducing erosion from arable land or protecting riverine riparian zones, recreating wetlands for controlling urban and agricultural diffuse pollution. Approaches such as constructed wetlands can also provide valuable services and benefits with respect to water supply, wastewater treatment and water flow regulation.

Mobilizing Action Toward Nature-Based Solutions

The International Water Association (IWA) has partnered with The Nature Conservancy (TNC) to mainstream nature based solutions in water infrastructure planning and spending by responding to IWA members interest in incorporating catchment management among the responsibility of utilities and their regulators. As part of this process, the International Water Regulators Forum, IWA Specialist Groups and other networks were mobilised to support the information needed for ensuring policies and regulations that promote nature based solutions in water management. Learn more about this research here.

A technical brief was developed with recommendations on how water utilities and water regulators can harness nature as a means of ensuring water security. 


IWA has a number of Specialist Groups that promote the use of nature-based solutions, and a specific task group for 2018-2020 has also been set up on Nature-based Solutions for Water and Sanitation. To find out the latest on what IWA members and partners are doing on NBS, join the IWA Specialist Groups below or follow the IWA Connect group on Nature-Based Solutions.


Wetlands Systems for Pollution Control Rainwater Harvesting and Management Wastewater Pond Technology
Diffuse pollution and eutrophication Urban drainage Watershed and River Basin Management

Nature for Water

By 2025, two thirds of the world’s population will be living in water stressed conditions. Meanwhile, the degradation of water ecosystems is occurring at alarming rates. Water utilities and water regulators that choose to play an active role in catchment management are uniquely positioned to help.

The International Water Association (IWA) and The Nature Conservancy (TNC) are working together to encourage and facilitate active utility involvement in watershed management and promote stronger connections between water utilities and regulatory bodies. The partnership aims to contribute new insights to the body of knowledge against which NBS can be assessed. Building a robust knowledge base and supporting opportunities for cross-sector collaboration are fundamental to the mainstreaming of these practices.

How can nature help achieve sanitation goals? How can achieving sanitation goals help nature?

There are 2.4 billion people living without sanitation properly separating them from their biological waste. For another 2.1 billion, wastewater drains directly into surface waters. Despite improvements over past decades, unsafe management of faecal waste and wastewater still presents a major risk to public health and the environment.

There are various natural solutions which can be part of wastewater treatment systems, supporting the removal of wastewater contaminants such as bacteria, heavy metals and high levels of nutrients. These include: constructed and natural wetlands, wastewater treatment ponds and soil infiltration systems, and green roofs and vertical gardens.

However, it is often difficult for wastewater utility managers to know whether to incorporate natural infrastructure into their planning, how best to find a suitable mix of grey and green infrastructure, and how to choose among the menu of possible types of green infrastructure. Many professionals, technicians and regulators, are hesitant to implement nature-based solutions, because the mechanisms at play are not well understood and controlled.

Nature-based Solutions Utility Spotlights

IWA and TNC have developed a publication “Nature for Water: a Series of Utility Spotlights” intended to shed light on the opportunities and challenges facing regulators and water utilities in their efforts to incorporate nature-based solutions into water management.

Nature for Sanitation

More than five billion people are expected to be without a connection to public sewerage in 2030. NBS can be part of traditional and decentralised wastewater treatment systems, reducing costs and providing other benefits.

The Working Group on Nature-based Solutions for Water and Sanitation brings together a diverse group of professionals developing practical guidance on how to more effectively use NBS for wastewater treatment in a way that benefits people as well as nature; and the use of modelling and scientific analysis to understand how implementation of sanitation goals will impact nature. Bringing these two areas together emphasizes the approach of linking science, policy and practice.

An important output of this group is the publication on Nature Based Solutions for Wastewater Treatment. This book serves as a compilation of technical references, case examples and guidance for applying nature-based solutions for treatment of domestic wastewater, and enables a wide variety of stakeholders to understand the design parameters, removal efficiencies, costs, co-benefits for both people and nature and trade-offs for consideration in their local context. Examples through case studies are from across the globe and provide practical insights into the variety of potentially applicable solutions. Access the full publication via IWA Publishing.

Events and webinars

May 17, 2018
Urban water utilities are mandated to collect and clean wastewater produced by the population. There are extensive treatment technologies such as constructed we...
April 10, 2018
Cities are intrinsically connected and dependent on water resources within and around their basins . Cities can integrate nature into urban infrastructure desig...
March 16, 2018
Investment in Nature Based Solutions (NBS) in the wider river basin is increasingly seen as a way to address urban water challenges such as floods, shortages in...


Related Blog Posts

October 26, 2023
The climate crisis demands urgent action across all sectors to reduce emissions and adapt to changing climatic conditions and sanitation is no exception. While ...
October 13, 2023
Water takes centre stage on this World Food Day, whose theme is ‘Water is life, water is food. Leave no one behind.’ The 2023 campaign, led by the Food and ...
While the water supply and sanitation sector in Uganda has undergone significant, systemic changes over the last decade, the 2009 Tariff Policy no longer spoke ...
Water is a vital resource that sustains life, drives economic development, and maintains ecological balance. Despite Rwanda's abundant rainfall, the water secto...
August 12, 2021
There are 2.4 billion people without improved sanitation and another 2.1 billion with inadequate sanitation (i.e. wastewater drains directly into surface waters...
August 10, 2020
The Zero program by Aguas de Portugal   With the last fully intact ice shelf collapsing this July 2020, we have hope that the water sector contributes to leadi...