Check out these grants that could be used for rain gardens, gardens or other projects involving fresh water:
GreenWorks! Grants (deadline end of September)
From Project Learning Tree (with the US Forest Service)
GreenWorks! is the service-learning component of PLT that provides grants to PLT trained educators for students to implement environmental improvement projects. By blending comunity service with the academic curriculum, students are "learning by doing."
Environmental Education (EE) Grants (deadlines in late winter)
From the US Environmental Protection Agency
EPA seeks grant proposals from eligible applicants to support environmental education projects that promote environmental awareness and stewardship and help provide people with the skills to take responsible actions to protect the environment. This grant program provides financial support for projects that design, demonstrate, and/or disseminate environmental education practices, methods, or techniques.
Every Day Capacity Building Grants (deadlines twice a year)
From the National Environmental Education Foundation with Toyota
Every Day Capacity Building Grants provide Friends Groups with grant funds of up to $2,000 to help build their capacity to serve public lands. Our nation’s public lands need our support every day. With stretched budgets and limited staff, land managers at federal, state and local public lands need all the help they can get. That help often comes from nonprofit organizations whose missions are focused on serving public land sites in the nation and the improvement and responsible use of those sites. Sometimes these organizations are called Friends Groups, sometimes Cooperating Associations, sometimes, simply a partner. They are invaluable in supporting, promoting and helping maintain public lands.
Captain Planet Foundation (deadlines twice a year)
Grants are made for activities that conform to the mission of the Captain Planet Foundation and MUST have all three of the following to be considered for funding: be project-based; performed by youth; and have real environmental outcomes. Grants from the Captain Planet Foundation are intended to: provide hands-on environmental stewardship opportunities for youth; serve as a catalyst to getting environment-based education in schools; and inspire youth and communities to participate in community service through environmental stewardship activities.
Nature Works Everywhere Garden Grants
From the Nature Conservancy (deadline in October)
Grants will be given in the amount of $1000–$2000 dependent upon the needs of the project. Funds may be used to support the building, amendment, or revitalization of gardens on school campuses, with preference given to rain, pollinator, native habitat, and other natural infrastructure projects. Food gardens will also be funded.