Stormwater Harvesting and Trades in a Sponge City

Full Solution
Stormwater reuse benefited from stormwater trade
China CCTV

In the Changsha City of Hunan Providence, China's first stormwater trade agreement was successfully launched and implemented thanks to the support and collaboration between government agencies and several private parties.  


On September 24, 2020, Changsha High-tech Zone Municipal Garden Sanitation Co., Ltd. and Hunan Yuchuang Environmental Protection Engineering Co., Ltd.(Yuchuang) signed a strategic agreement to buy and sell harvested stormwater resources in some Sponge City communities, creating a new model of the utilization of stormwater and supporting the sustainability of Sponge City implementation. 


Harvested stormwater in selected Sponge City facilities can be sold at a price 20% lower than the local tap water price, creating an incentive for stormwater harvesting and reuse.  The stormwater is later used in landscaping irrigation, waterscape supplementation, dust control, etc.



Last update: 26 Sep 2022
Challenges addressed
Erratic rainfall
Storm surges
Inefficient management of financial resources
Infrastructure development
Lack of access to long-term funding
Lack of alternative income opportunities
Lack of infrastructure

The long-term funding stream for Sponge City is very crucial. Since most private sectors lack interest in investing in Sponge City projects, and stormwater fees are also far from being implemented in most cities in China.  Other funding sources for Sponge City implementation are needed to support the construction and O&M.  


The current stormwater trading system is still on a pilot scale.  One major challenge is that water and stormwater rights are still not clear in China.  Thus the trading system in its current format is still more government-mandated than market-driven, which needs to be improved in the near future. 

Scale of implementation
Area-wide development
Buildings and facilities
Green spaces (parks, gardens, urban forests)
Sustainable financing
Infrastructure maintenance
Watershed management
Outreach & communications
Water provision and management
Changsha, Hunan, People's Republic of China
East Asia
Summary of the process

Experts in water trade, water resources management, and stormwater management were invited and served on a technical committee to educate the representatives of all parties, as well as conduct educational events for the residences.  We learned that communications during outreach and collaboration are important to bring people with different backgrounds together to reach a win-win agreement.



Building Blocks
Stormwater Public Education and Outreach

At the early stage of the trading platform planning, public education and outreach were conducted to promote the Sponge City concept and to introduce trade. 


Many local community residents come to visit and learn, which stimulated the residents' interest in the utilization of rainwater resources.

Enabling factors

Public seminars and meetings near the site have also been arranged to meet the needs of different parties, from local residents to professionals.  The community rainwater collection system has signs, posters, and billboards designed for local residences' and students' environmental education.   





Lesson learned

It takes time for the local residents to learn new things.  Sponge City is a new concept in China, and so is the stormwater trade.   Public education and outreach need to be planned before the design and construction of facilities, so the residents can be noted at the very beginning from the design, construction, and operations.


It is also important to have educational materials near some demonstration sites to introduce Sponge City and rainwater harvesting, etc. 


In some communities in Changsha, this effort has been implemented at the very beginning of the Sponge City initiative, which greatly allows the stormwater trade being progressed smoothly.  


Residents of the local community who participated in the transaction expressed their support for rainwater harvesting, reuse, and trades.

Public-Private Multi-Party Collaboration

Local government authorities and a few private parties are involved in the trade.  Collaboration is greatly appreciated which is the key to the success of the stormwater trade. 

Enabling factors

Public and private parties have the willingness to collaborate for a common goal, which is to better utilize stormwater as a resource, save tap water usage, and reduce the costs such as landscape irrigation.


Conferences, seminars, and meetings were arranged to allow learning and discussions on building the stormwater trading platform.  


Lesson learned

Since this is something new in China, international experience and case studies were introduced by technical committee experts which help the parties understand the common goals and evenly reach the agreements.



The goal of Sponge City, which is required by the Chinese government,  is to manage and retain approximately 70% of the stormwater runoff in 80% of urban lands by 2030. This creates a good opportunity to reuse the stormwater and sell excessive water resources to other parties.


Since 2014, the harvested rainwater of Yuchuang can reach 1 million to 2 million cubic meters per year, and its value can be up to 1.5 million yuan (0.21 million US$).  This actually only accounts for a very small portion of total rainwater resources in Changsha City.  


It was the first in China that the rainwater can be traded on a state-run exchange, as a small step toward reallocating water resources to solve its water crisis.


1) Property Owner:

Gain 0.7 yuan (US$0.11) per cubic meter of rainwater;

2) Yuchuang: 

Sell after a good markup at 3.85 yuan (US$0.60), 

3) Landscaping Company:

The price is still 20 percent cheaper than the tap water price, a good cost-saving.


Sustainable Development Goals
SDG 6 – Clean water and sanitation
SDG 11 – Sustainable cities and communities
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Other contributors
Liu, Bo
CSEC -Changsha Sponge City Eco-Industry Technology Innovation Strategic Alliance