This section provides information on the Clean Water Act and stormwater management including green infrastructure. The objective of the Clean Water Act is to “restore and maintain the chemical, physical, and biological integrity of the nation’s waters.” The act generally prohibits the discharge of pollutants from “point sources”— such as discharge pipes from industrial facilities and wastewater treatment plants––without an NPDES permit. The act specifies that NPDES permits may not be issued for a term longer than 5 years. In 1987, Congress amended the Clean Water Act to require that EPA implement a comprehensive national program for addressing stormwater discharges; EPA implemented the program in two phases. In the first phase, EPA regulated stormwater discharges from large and medium municipal separate storm sewer system. In the second phase, EPA extended these requirements to smaller systems. Municipalities include cities, towns, villages, or other public entities that provide residents with services, such as drinking water and sewage treatment. Municipalities can have one or both types of stormwater systems, a municipal separate storm sewer system or a combined sewer system. Figure 2 illustrates the components of the two types of systems and how a CSO occurs. In 1990, EPA issued a regulation implementing the first phase of the stormwater program, requiring municipalities serving populations of 100,000 or more to obtain permits for stormwater discharges. In 1999, EPA implemented the second phase by expanding NPDES permit requirements to smaller municipalities. Generally, permits effectively prohibit non-stormwater discharges into storm sewers, and require controls to reduce pollutant discharges to the maximum extent practicable, including the use of best management practices. These practices generally include identifying and eliminating illicit discharges; preventing construction site runoff and post-construction site runoff; and preventing pollution from certain commercial, industrial, and residential areas. Such practices could also include distributing materials with utility bills to help educate the public on activities like cleaning up pet waste and household chemicals, implementing street sweeping to eliminate trash and debris, and training and certifying construction contractors. To manage CSO pollution, in 1994, EPA issued its Combined Sewer Overflow Control Policy, which provides guidance on how to meet the Clean Water Act’s pollution control goals through NPDES permits issued to municipalities with combined sewer systems. Specifically, the policy provides guidance on coordinating the planning, selection, and implementation of CSO controls that meet the requirements of the Clean Water Act. In 2000, Congress amended the Clean Water Act to require that NPDES permits for discharges from combined sewer systems comply with EPA’s Combined Sewer Overflow Control Policy. Actions that can be taken to reduce the number and volume of discharges from a combined sewer system can include separating storm sewer and sanitary sewer systems and building larger tunnels to hold stormwater runoff until it can be treated and discharged by a wastewater treatment plant. When Clean Water Act requirements are violated—for example, when a municipality has an unauthorized CSO event—EPA and states may, among other things, bring suit in court. These suits can result in consent decrees under which a municipality agrees, for example, to take corrective actions to reduce the number and volume of CSO events. In 1998, EPA’s Office of Enforcement and Compliance Assurance began a National Enforcement Initiative to focus enforcement action on keeping raw sewage and contaminated stormwater out of the nation’s waters. According to an EPA official, the agency has addressed noncompliance with stormwater and wastewater requirements of the Clean Water Act by entering into consent decrees with over 50 municipalities from 1998 through 2016. Municipalities use green and gray infrastructure to manage stormwater and meet the requirements of permits and consent decrees. Gray infrastructure refers to sewer structures that are typically made of materials, such as concrete or metal, designed to collect and channel stormwater runoff from impervious surfaces, such as city streets and parking lots, to a wastewater treatment plant or nearby creeks, lakes, and rivers. Green infrastructure includes practices and structures to manage stormwater that use or mimic natural processes to slow stormwater runoff, filter pollutants from the runoff, and facilitate stormwater storage for future use or replenishing groundwater and aquifers. Figure 3 illustrates how green infrastructure allows stormwater to penetrate (seep into) the soil and replenish groundwater and aquifers. Municipalities can meet permit and CSO consent decree requirements using either green or gray infrastructure, or a combination of both. For example, both types of infrastructure can limit the amount of pollutants that stormwater washes into nearby water bodies. Green infrastructure can filter out the pollutants, and gray infrastructure can convey the combined stormwater and wastewater to a wastewater treatment plant. Similarly, both types of infrastructure can prevent CSO events. Green infrastructure can reduce the volume of stormwater entering a combined sewer, and if gray infrastructure has sufficient capacity, the combined sewer will not be overwhelmed during storm events. Since 2007, EPA has encouraged municipalities to use green infrastructure to help meet the requirements of permits and CSO consent decrees. In April 2007, the EPA Administrator entered into an agreement with state, environmental, and wastewater utility groups to promote the use of green infrastructure in reducing stormwater pollution and mitigating CSOs. In August 2007, EPA issued a memorandum stating that EPA regional offices and states may encourage the use of green infrastructure, where appropriate, in meeting permit requirements and CSO consent decrees. According to EPA officials we interviewed, the agency worked with a number of partners, including other federal agencies and nonprofit groups involved in water management, conservation, and housing and development, to promote the use of green infrastructure. EPA developed a strategic plan to help communities use green infrastructure in 2008 and updated it in 2011 and again in 2013. EPA’s latest plan, the 2013 Green Infrastructure Strategic Agenda, includes five goals: Green infrastructure practices are embedded in federal agency programs. Green infrastructure language in permitting and enforcement actions is common practice. Data on the design, performance, costs, and benefits of green infrastructure is known and readily available. Decrease the financial burden to communities of installing and maintaining green infrastructure. Communities across the country are networking and exchanging information on the best green infrastructure approaches. EPA’s website illustrates different types of green infrastructure, with 11 examples. Figure 4 shows the 11 examples of green infrastructure listed on EPA’s website. Most of the 31 municipalities we surveyed use green infrastructure to comply with NPDES permits or CSO consent decrees, but almost half said that less than 5 percent of the area covered by their permits or consent decrees drains into green infrastructure. About three-quarters of the municipalities said that they fund green infrastructure through general revenues and stormwater fees charged to utility customers or residents of the municipality. Of the 31 municipalities we surveyed, 30 reported using at least 1 of the 11 examples of green infrastructure presented on EPA’s website to help meet the provisions of their permits since 2012 or the provisions of their CSO consent decrees. For each of the 11 green infrastructure types, municipalities reported whether to comply, at least in part, with their permit or consent decrees they (1) used or installed the type of green infrastructure themselves or (2) encouraged or required property owners to use or install the type of green infrastructure. Twenty-eight municipalities reported that they used or installed a type of green infrastructure and encouraged or required property owners to use or install a type of green infrastructure. Two municipalities reported that they had not used or installed any green infrastructure themselves but had encouraged or required property owners to use or install a type of green infrastructure. Of the 11 types, the 3 most used or installed by municipalities—or that municipalities encouraged or required their customers to use—were downspout disconnection, rain gardens (also known as bioretention), and permeable pavement. Figure 5 illustrates how many of the 30 municipalities reported using or installing 1 or more of the 11 types of green infrastructure themselves and how many municipalities reported that they encouraged or required private property owners to use or install a type of green infrastructure. In addition to the green infrastructure types identified in figure 5, the municipalities we surveyed also identified other green infrastructure that they used to help meet permit or consent decree requirements. For example, one municipality said that it used habitat restoration and similar efforts to address stormwater runoff. Another municipality reported using an infrastructure system that collected water underneath a parking lot where it could penetrate the soil below the paved surface. The one municipality that reported not using green infrastructure to help comply with the provisions of its consent decree said that there was insufficient public land on which to install green infrastructure and that the type of soil in the area subject to the decree, blue marine clay, is not permeable enough to allow green infrastructure to filter water through the soil. However, the same municipality said that the community that it served was generally receptive to using green infrastructure to manage stormwater and that it uses green infrastructure in other areas of the community not included in the terms of the consent decree. Of the 30 municipalities that reported using green infrastructure to help meet the provisions of their permits or CSO consent decrees, many of them also reported on the percentages of the areas subject to permits or consent decrees that drain into green infrastructure, with the remaining areas draining into gray infrastructure or directly into creeks, lakes, or rivers. Twenty-seven municipalities provided us with information about how much of the areas subject to permits or consent decrees drains into green infrastructure and how much drains into gray infrastructure or elsewhere. Of these 27 municipalities, 15 reported that less than 5 percent of the relevant areas drained into green infrastructure, while 6 municipalities reported that more than 20 percent of the area subject to permits or consent decrees drained into green infrastructure. The remaining 6 municipalities reported that from 5 percent to 20 percent of the relevant areas drains into green infrastructure. Figure 6 provides additional information on the percentages of areas subject to municipalities’ permits or consent decrees that drain into green infrastructure. Of the 30 municipalities that reported using green infrastructure to help comply with the provisions of their permits or CSO consent decrees, 24 municipalities reported using general revenues or specific fees for stormwater management levied on utility customers or municipal residents to fund capital expenditures for green infrastructure over their last 3 fiscal years. Of the remaining 6 municipalities, 2 reported using sales tax revenues or federal grant funding as the sole source of funding, 2 said that they had no capital expenditures for green infrastructure in the last 3 fiscal years, and 2 did not respond to the question. Of the 24 municipalities that reported using general revenues or stormwater fees to fund capital expenditures for green infrastructure to help comply with the provisions of permits or CSO consent decrees, 14 reported that they also used funding from one or more additional sources. Six reported that they also used federal grant funding to help pay for capital expenditures on green infrastructure, 5 said that they also used funding from their state’s Clean Water State Revolving Fund, and 5 said that other nonfederal grants were a source of funding for their green infrastructure. Some municipalities also identified additional sources of revenue to fund capital expenditures for green infrastructure, including fees on new development. Of the 30 municipalities that reported using green infrastructure to meet the provisions of their permits or CSO consent decrees, 17 provided information comparing their capital expenditures for green infrastructure to capital expenditures for gray infrastructure. The remaining municipalities either did not have information that distinguished between capital expenditures on green infrastructure and gray infrastructure or they did not provide us with that information. The amount that the 17 municipalities reported spending on capital expenditure for green infrastructure varied from a 3-year average of about $5,000 to about $5.9 million. The amount that the municipalities reported spending on capital expenditure for gray infrastructure varied from a 3-year average of about $18,000 to about $208.2 million. Of the 17 municipalities that provided data comparing their capital expenditures for green infrastructure to capital expenditures for gray infrastructure, 11 (65 percent) reported spending approximately 20 percent or less of capital expenditures on green infrastructure, including 7 municipalities that reported spending less than approximately 5 percent on green infrastructure. Conversely, 6 of the 17 municipalities reported spending more than approximately 20 percent of capital expenditures on green infrastructure, including 3 municipalities that reported spending more than 60 percent on green infrastructure. Overall, the 17 municipalities reported spending an average of about 24 percent of their capital expenditures for meeting the provisions of their permits or CSO consent decrees on green infrastructure, with the remaining amount spent on gray infrastructure. Most of the 31 municipalities (26) we surveyed reported that one or more aspects of infrastructure development involved with projects to help meet the provisions of their NPDES permits or CSO consent decrees were usually more challenging when using green infrastructure than when using gray infrastructure. However, the municipalities also reported continuing to use green infrastructure. In our survey, we asked the 30 municipalities that reported using green infrastructure to help meet the provisions of their permits or CSO consent decrees about eight aspects of infrastructure development that may have challenged municipalities when using green infrastructure. For each aspect, we asked municipalities if the aspect was usually more challenging for green infrastructure, usually less challenging, or about the same when compared to gray infrastructure. 1. obtaining land to install green infrastructure, 2. developing capital expenditure estimates for green infrastructure, 3. developing operation and maintenance estimates for green 4. designing and engineering green infrastructure, 5. installing green infrastructure, 6. overall cost of using green infrastructure, 7. confidence in the effectiveness of green infrastructure, and 8. political and public opinions regarding green infrastructure. As shown in figure 7, 15 of 30 municipalities reported that four or more of the eight aspects were usually more challenging for green infrastructure than for gray infrastructure. One municipality said that all eight of the aspects were usually more challenging for green infrastructure than for gray infrastructure. Two municipalities reported that no aspects were usually more challenging for green infrastructure than for gray infrastructure. Municipalities most often cited the following aspects of infrastructure development as being more challenging for green infrastructure than for gray infrastructure: developing a capital expenditure estimate, developing an operation and maintenance cost estimate, and designing and engineering a project. Of the 30 municipalities that reported using green infrastructure, 22 reported that developing an operation and maintenance cost estimate was usually more challenging than doing so for gray infrastructure, while none said that it was usually less challenging. Similarly, 16 municipalities reported that developing a capital expenditure estimate for green infrastructure was usually more challenging than doing so for gray infrastructure, while none said that it was less challenging. Finally, 16 municipalities reported that designing and engineering a project was usually more challenging for green infrastructure than for gray infrastructure, while 3 said that it was usually less challenging. Figure 8 shows the number of municipalities that reported for each of the eight aspects whether they were usually more challenging, usually about the same, or usually less challenging when using green infrastructure compared to using gray infrastructure. Figure 8 also shows that political and public opinion regarding green infrastructure was the one aspect that municipalities cited as usually less challenging for green infrastructure than for gray infrastructure. In explaining why these aspects of infrastructure were more challenging for green infrastructure, municipalities most commonly reported that they were not familiar with green infrastructure. For example, when describing their unfamiliarity with green infrastructure, representatives of one municipality said that with gray infrastructure, the maintenance activities and costs associated with traditional sewers are known from experience. For green infrastructure, however, they said that they needed to increase cost estimates for maintenance activities to account for unforeseen events. Representatives of another municipality, referring to gray infrastructure, said they know what it costs to put a pipe in the ground but do not have the skill set or experience to estimate the capital costs of green infrastructure. Discussing the costs associated with maintaining green infrastructure, representatives of another municipality said they hired staff with horticultural expertise to maintain rain gardens because they were unsure about the requirements necessary to maintain them. Another municipality said that it had difficulties finding qualified personnel to assist its engineers with green infrastructure. Of the 26 municipalities that reported that green infrastructure was usually more challenging than gray infrastructure for at least one aspect, 25 reported that there were instances where they used green infrastructure anyway. In describing instances where they used green infrastructure even though it was more challenging, some municipalities reported that they continued to use green infrastructure to help comply with their permits or CSO consent decrees for three primary reasons: they saw using green infrastructure as a learning opportunity, they believed that green infrastructure would perform better or provide additional benefits compared to gray infrastructure, or the community wanted to use green infrastructure. Municipalities expressed a desire to learn from their experiences with green infrastructure. For example, a municipality said that it had to rebuild some green infrastructure—add new soil and replant vegetation—because it let maintenance slide because of budget issues. Representatives of this municipality said that understanding how to plan appropriately for operation and maintenance is part of the learning process associated with using green infrastructure. Another municipality was more specific, with representatives saying that the city had installed permeable pavement on a section of street as an opportunity to learn about permeable materials, especially the maintenance needed to ensure that permeable pavement continues to function properly. Some municipalities reported that using green infrastructure was a better option than using gray infrastructure to address their stormwater management needs. For example, representatives of one municipality said that although they had less experience with green infrastructure, they used it anyway because it was a better option than using pipes and concrete to reduce the flow of stormwater and the amount of contaminants in stormwater. Representatives of another municipality said that they used green infrastructure because it met other project objectives: it was more aesthetically pleasing, it “fit” into the neighborhood better, and it replenished groundwater. These municipality representatives noted that most of the town’s water comes from groundwater wells. Some municipalities also reported that they were committed to using green infrastructure even though it was more challenging than using gray infrastructure on one or more aspects. For example, representatives of one municipality said that their city made a pledge to use green infrastructure. They said the city made the investment and set goals for green infrastructure, and although it is more difficult to generate cost estimates, the municipality continues to pursue green infrastructure. Another municipality said that there was not much data on the long-term costs of caring for the plants used in bioswales under the drought conditions that the municipality was currently experiencing. Nevertheless, the officials said the municipality installed the bioswales because doing so was supported by the public and an environmentally conscious city council interested in aesthetics and habitat restoration. Conversely, of the 26 municipalities that reported that at least one aspect was usually more challenging when using green infrastructure than when using gray infrastructure, 19 reported instances where they were discouraged from using green infrastructure because it was more challenging than using gray infrastructure. We asked municipalities to describe these instances. Some municipalities reported that they were discouraged from using green infrastructure because they were not familiar with it, because conditions specific to the area under consideration were not conducive to using green infrastructure, and because green infrastructure was more expensive than gray infrastructure. For example, describing their unfamiliarity with green infrastructure, representatives of one municipality said that because they were trying to meet the provisions of their consent decree, they needed an option that they had high confidence would meet the provisions. They believed that green infrastructure was not a proven technology. Representatives from another municipality said that while there had been a high turnover in city engineers and that the newer staff was amenable to using green infrastructure, the longer tenured engineers who were reluctant to use green infrastructure had an outsized influence on whether the engineering department would do so. Several of the municipalities reported that they were discouraged from choosing green infrastructure because conditions in the area under consideration were not conducive to using green infrastructure, including that there was not enough land in the right place to use green infrastructure or that the area was too arid. For example, representatives from one municipality said that they were considering bioretention measures to reduce CSOs, but there was not enough available land to make this option viable. They said that because of the topography of the town, any bioretention measures would need to be placed near the center of town, but because it was the center of town, there was no room for bioretention measures. Representatives from another municipality said that widening a road to meet fire protection requirements consumed the green space available for green infrastructure and that buying a right of way was cost prohibitive. Representatives from a third municipality said that installing green infrastructure in a city’s historic district would change the character of the area and could consume limited parking spaces— thus engendering negative public opinion. Municipalities also said that arid conditions discouraged them from installing green infrastructure in some instances. For example, representatives from one municipality said that because their municipality is in a semiarid climate that makes it difficult to establish grasses, they try to predict whether the upcoming season will be wet or dry and install green infrastructure accordingly. They said that if they do not predict correctly, the plants will die and the funds spent on green infrastructure will have been wasted. Several municipalities also reported that they were discouraged from using green infrastructure because it was more expensive than using gray infrastructure. For example, representatives from one municipality said that green infrastructure was more costly than gray infrastructure because of the cost of the land that would need to be purchased to install it. Representatives from another municipality said that green infrastructure would need to be installed in a flat area near the river and that in some instances the city did not own the surface area necessary to install green infrastructure but did own an easement to install gray infrastructure underground. The representatives said that the city was unable or unwilling to purchase such surface rights. Representatives from a third municipality said they did not have the in-house expertise to design green infrastructure and were discouraged from using green infrastructure because of the cost to hire outside consultants with that expertise. Over the last 10 years since EPA began encouraging the use of green infrastructure to manage stormwater, the agency’s efforts have provided information, technical assistance, and funding to help municipalities use green infrastructure. In addition, in 2016, EPA began a pilot project to assist five municipalities in developing long-term stormwater plans that would allow more time to incorporate green infrastructure practices but has not yet developed written agreements documenting how they will work together to collaborate. Since 2007, when EPA began encouraging the use of green infrastructure to manage stormwater, EPA has provided information, technical assistance, and funding for green infrastructure to help municipalities incorporate green infrastructure into their stormwater systems. The goals of the green infrastructure program, as described in EPA’s 2013 Green Infrastructure Strategic Agenda, are (1) embedding green infrastructure in federal agencies; (2) making green infrastructure language in permitting and enforcement actions common practice; (3) making data on design, performance, costs, and benefits of green infrastructure known and readily available; (4) decreasing the financial burden to communities of installing and maintaining green infrastructure; and (5) establishing partnerships and capacity building, where communities are networking and exchanging information on the best green infrastructure approaches. The goals most relevant to EPA’s providing assistance to municipalities to employ green infrastructure are the latter three, providing information, funding, and partnerships and capacity building. To address the goal of making information available on the design, performance, costs, and benefits of green infrastructure, EPA has provided extensive information on its website, including sharing its own research and that of academics, nonprofit groups, and other entities on a variety of issues related to green infrastructure. For example, the website contains links to documents and databases from EPA, universities, and others on the performance and benefits of specific green infrastructure technologies, such as a report summarizing results from research conducted by EPA’s Office of Research and Development into the performance of several green infrastructure practices. The website also contains links to technical webcasts for public officials and green infrastructure practitioners concerning specific green infrastructure practices, such as design, operation, and maintenance, including a webcast addressing strategies on designing, implementing, and maintaining green infrastructure at the local level and a webcast on the cost- savings and benefits of using green infrastructure, and fact sheets and supplemental materials that EPA has developed to provide examples of how green infrastructure can be incorporated into permits and other compliance agreements, such as CSO consent decrees. In addition, since 2012 EPA has provided $2.8 million in technical assistance to 52 municipalities for planning and implementing green infrastructure. On the basis of this work, EPA has posted on its website case studies focused on the use of green infrastructure options to address a variety of site-specific issues related to green infrastructure, such as flood mitigation, the capture of stormwater for reuse for irrigation of parkland, adaptation to climate change, the integration of green infrastructure into transportation planning, and addressing barriers to using green infrastructure. For example, in one case study, EPA identified green infrastructure options for a low-lying coastal area subject to sea level rise. In another case study, EPA worked with a city to develop a conceptual design for a 100,000-gallon storage tank that the city will use to harvest stormwater from a storm drain system, reducing runoff and using the water to irrigate parkland. In addition, EPA also issued a summary report to convey the overall lessons learned in the technical assistance projects. To address the goal of decreasing the financial burden to communities of installing green infrastructure, EPA has provided funding for green infrastructure to municipalities. For example, since 2009, the Green Project Reserve (GPR), which is part of the agency’s Clean Water State Revolving Fund, has provided $944 million for green infrastructure project loans to municipalities, according to EPA’s website. Green infrastructure projects funded under the GPR have included (1) urban reforestation in one city that has served the dual purpose of reducing stormwater runoff and promoting urban revitalization in an economically distressed area and (2) in another city, a bioengineered stream and constructed wetland that reduced stormwater runoff by enhancing water infiltration into the ground while creating a public gathering space. EPA also provides funding under other programs for green infrastructure, including through Clean Water Act Nonpoint Source Grants and through its Urban Waters Small Grants Program, Five Star and Urban Waters Restoration Grants Program, and Greening America’s Communities Program, among others. To address the goal of establishing partnerships and capacity, EPA officials said that they held a series of national community summits to encourage peer-to-peer exchange for better stormwater management from 2013 to 2015. The agency now works with a network of municipalities, which was created in 2015, focused on effectively using green infrastructure. The network brings together green infrastructure practitioners from different communities to help them learn from each other as they use green infrastructure. In addition to collaborating with this network, EPA developed a web application called the Green Infrastructure Wizard to connect communities to EPA green infrastructure tools and resources and maintains an electronic mailing list called GreenStream to help share publications, training, and funding opportunities. EPA officials said that they also sponsored efforts to educate students in the use of green infrastructure. Since 2012, EPA has held the Campus RainWorks Challenge, an annual competition for college students, with the intention of exposing future engineers and designers to green infrastructure concepts. In these challenges, college students form teams, each with a faculty sponsor, and design innovative green infrastructure projects for their campuses to effectively manage stormwater. In 2016, according to EPA’s website, student teams from 30 states submitted designs that were judged by representatives from EPA and its cooperating organizations—the American Society of Landscape Architects, the American Society of Civil Engineers, and the Water Environment Federation. In 2016, EPA conducted an informal assessment of its progress in advancing the use of green infrastructure and determined that the information, assistance, and funding that the agency provided had not resulted in communities institutionalizing green infrastructure in a similar fashion to gray infrastructure. EPA officials we interviewed said that they regarded the early years of the agency’s green infrastructure program as an educational phase that increased awareness of the use of green infrastructure in managing stormwater. However, these officials said that they have found that while municipalities are now generally aware of green infrastructure, they are not using it extensively to manage stormwater, and the officials identified challenges for the municipalities in installing green infrastructure. The officials said that fully integrating stormwater management into other community planning efforts requires a sufficiently long time horizon to help maximize environmental benefits and provide cost efficiencies by synchronizing a community’s plans with its stormwater management and any Clean Water Act obligations; this horizon is likely longer than the current 5-year permit window and the agency is exploring how to incorporate long-term planning approaches into permit conditions. EPA officials said that while it is possible to implement many practices on an ad hoc basis, comprehensive implementation across a municipality’s stormwater area can take multiple permit cycles. The EPA officials said that the agency would like communities to be more easily able to integrate green infrastructure into capital improvement plans and other municipal plans to realize the most effective environmental benefits and cost savings. In addition, EPA officials said that since green infrastructure is relatively new, municipalities do not know if using green infrastructure will meet the requirements of their permits and thus may be discouraged from using it. To address these challenges to installing green infrastructure, EPA officials said that they would develop a new focus on helping municipalities find ways to incorporate green infrastructure into stormwater systems over a longer period of time while still meeting permit requirements. The officials said that beginning in 2016, they launched a pilot project to work with 5 municipalities to develop long-term stormwater plans that incorporate green infrastructure. The officials said that they plan to work with these municipalities to identify projects to address stormwater management, including meeting permit requirements, while developing and implementing larger infrastructure and community plans that address other needs, such as transportation or recreation. According to EPA officials, the long-term stormwater plans will include projects that will be implemented over the course of multiple permit cycles—perhaps as long as 20 to 30 years. The long-term stormwater plans will be incorporated into permits, to show how the permits’ requirements to limit or eliminate stormwater pollution will be met. According to an EPA official, a municipality’s long-term stormwater plan would be reevaluated when its stormwater permit is renewed. EPA officials said that one purpose of the pilot project will be to help integrate a municipality’s long-range stormwater plan into its shorter-term permits. EPA officials also said that the idea of the pilot project is to demonstrate to other municipalities the benefits of using a long-term approach to planning for green infrastructure and stormwater management. According to the officials, this long-term approach can be more cost-effective for municipalities installing green infrastructure and can help reduce the costs of complying with permit requirements. More specifically, agency officials we interviewed said that by incorporating stormwater management at the same time as other infrastructure projects, such as transportation projects, the costs of implementing green infrastructure could be reduced while balancing other community priorities. For example, a park that includes green infrastructure features, such as bioswales, will serve two purposes, providing both recreational area and stormwater drainage, and the costs to install permeable pavement are not as high if the work is synchronized with other repaving projects, such as adding bike lanes. EPA officials we interviewed said that through the pilot project, the agency plans to establish groups in five municipalities to work collaboratively on developing long-term stormwater plans. By working with each municipality for at least 12 to 18 months, EPA officials said that they intend for each municipality to form a group of stakeholders that will collaborate to integrate green infrastructure into long-range plans that may include other municipal infrastructure elements, such as parks or streets. The participants for each of the five municipalities will include EPA; its consultants; the municipal department responsible for stormwater; potentially state NPDES permitting authorities; other municipal departments, such as for roads or parks; interest groups; and members of the general public. The participants may vary, depending on the municipality and other potential infrastructure improvements the municipality may be planning, and EPA officials said that they will work with stormwater officials in each municipality to identify the appropriate local agencies and other stakeholders that need to be involved in developing the stormwater management plan. The use of such a collaborative group is consistent with one of the mechanisms to implement interagency collaborative efforts that we identified in a 2012 report on key considerations for implementing interagency collaborative mechanisms. That report discusses different types of collaborative mechanisms, such as a coordinator appointed by the President or an interagency task force. In that report, we also identified that all collaborative mechanisms benefit from certain key features, which raise issues to consider when implementing these mechanisms. These issues are shown in table 1. EPA officials said that they have agreements with each municipality that the agency will provide each group with technical assistance. EPA officials also said that they would provide $150,000 to each municipality, for a total of $750,000 for the pilot. When we asked about what resources or documents EPA would use to guide the pilot project and the work with the five municipal groups, EPA officials referred us to the following agency resources that provide guidance to communities and wastewater utilities for planning for sustainability and managing stormwater planning more generally. Community Solutions for Stormwater Management: A Guide for Voluntary Long-term Planning (2016). According to the guide, it describes how to develop a comprehensive long-term community stormwater plan that integrates stormwater management with a municipality’s broader plans for economic development, infrastructure investment, and environmental compliance. The document says that when developing a plan, a community should determine and define the scope of the integration effort, ensure the active participation of entities that are needed to implement the plan, and identify the role each entity will have in implementing the plan. EPA officials said that this document outlines the approach they will use for the pilot projects. EPA is also developing a web-based Toolkit that will include technical and financing resources to walk communities through the long-term stormwater planning process provided in the Community Solutions for Stormwater Management guide Integrated Municipal Stormwater and Wastewater Planning Approach Framework (2012). According to the document, it is for use by EPA, states, and local governments to develop and implement integrated plans under the Clean Water Act. Steps for developing a plan include defining the scope of the integration effort, ensuring participation of the entities needed to implement the integrated plan, and identifying the role each entity will have in implementing the plan. EPA officials said that the pilot project’s approach to long-term planning reflects EPA’s Integrated Planning Framework. In addition, we identified other EPA resources which include some features that we have identified as being helpful for collaborative groups. These documents include the following information: Green Infrastructure in Parks: A Guide to Collaboration, Funding, and Community Engagement (2017). According to the guide, it is intended to encourage partnerships between park agencies and stormwater agencies aimed at promoting the use of green infrastructure on park lands. It identifies steps to facilitate the implementation of green infrastructure in parks, including identifying and engaging stakeholders; building relationships; leveraging funding opportunities; and undertaking high-visibility pilot projects, which it says helps gain support for more green practices. Planning for Sustainability: Handbook for Water and Wastewater Utilities (2012). According to the handbook, it is intended to provide information about how to enhance current planning processes by building in sustainability considerations. It is designed to be useful for various types and scales of planning efforts, such as long-range integrated water resources planning. The steps include the utility internally identifying sustainability priorities and potential opportunities and engaging the community about its sustainability priorities. Key to the success of the five groups is collaboration among the participants as they develop their long-range stormwater plans. Although EPA officials said that the documents they provided were not intended to include how EPA, municipal departments, and other stakeholders are to collaborate, they reflect some of the key considerations for implementing interagency collaborative mechanisms that we identified in our past work. For example, the two 2012 documents identify the need for appropriate participants to be involved in a collaborative group, and the 2016 document discusses the need to identify the roles that each entity will have in implementing a plan and to define the scope of the effort. In addition, the 2017 park planning document states that identifying opportunities to provide resources through leveraging funds can help incorporate green infrastructure features into a park, while at the same time accomplishing other purposes, such as providing trails and irrigation for sports fields. EPA officials we interviewed said that the efforts with the five municipal groups have just started and that they have not developed further guidance for how to collaborate with the municipalities and relevant stakeholders. In particular, EPA officials said that the five groups have not yet developed agreements on how they will work together to collaborate. According to the officials, they are working on additional resources to provide further details about options to engage communities, promote accountability, prioritize goals and actions, and identify financing options. Our prior work has found that agencies that articulate their agreements in formal documents, such as memorandums of understanding, can strengthen their commitment to working collaboratively. A written document can incorporate agreements reached among participants in any or all of the following areas: leadership, accountability, roles and responsibilities, and resources. When working with the five groups in the pilot project, EPA could better assure that they will successfully develop long-term stormwater plans if they document their agreement on how they will collaborate, such as in a memorandum of understanding, aligned with our key considerations for implementing interagency collaborative mechanisms. Similarly, any other efforts to develop long-term stormwater plans after the pilot project would benefit from the groups documenting their agreement on how they will collaborate. In the last 10 years, EPA’s green infrastructure program has focused on educating municipalities by providing information, technical assistance, and funding and, as our survey results show, has helped municipalities achieve familiarity with the general concept of green infrastructure. Yet EPA officials we interviewed believe that they are now at a turning point in this program, noting that green infrastructure is still not a prominent component of most municipal stormwater programs. EPA’s pilot project with five municipalities is a good way to focus on developing long-term stormwater plans. However, the success of EPA’s pilot project—and any other efforts to develop long-term stormwater plans after the pilot project—depends on successful collaboration among wide-ranging groups of participants. Our previous work on key considerations for implementing interagency collaborative mechanisms, such as the municipal groups proposed by EPA, provides more specific ways for groups to work together than what is currently contained in EPA documents. That work has also found that agencies that articulate their agreements in formal documents, such as memorandums of understanding, can strengthen their commitment to working collaboratively. When working with the municipal departments and other stakeholders, such as those in each of the five groups in the pilot project, EPA could have a better assurance that the groups will successfully develop long-term stormwater plans if they document their agreement on how they will collaborate, such as in a memorandum of understanding, aligned with our key considerations for implementing interagency collaborative mechanisms. The Director of EPA’s Office of Wastewater Management should, when working with municipalities and other stakeholders to develop long-term stormwater plans, document agreements on how they will collaborate, such as in a memorandum of understanding, aligned with our key considerations for implementing interagency collaborative mechanisms. (Recommendation 1) We provided a draft of this report to EPA for review and comment. In its written comments, reproduced in appendix III, EPA generally agreed with our findings, conclusions, and recommendation. EPA stated that it is in the early stages of the pilot project to assist municipalities in developing long-term stormwater plans and will utilize the collaborative practices recommended by GAO as it implements the project over the next 12 to 18 months. EPA’s plans, if implemented as described, would address our recommendation. EPA also provided technical comments, which we incorporated as appropriate. As agreed with your office, unless you publicly announce the contents of this report earlier, we plan no further distribution until 30 days from the report date. At that time, we will send copies of this report to the appropriate congressional committees; the Administrator of the Environmental Protection Agency; the Director, Office of Management and Budget; and other interested parties. In addition, this report will be available at no charge on the GAO website at http://www.gao.gov. If you or your staff members have any questions about this report, please contact me at (202) 512-3841 or gomezj@gao.gov. Contact points for our Offices of Congressional Relations and Public Affairs may be found on the last page of this report. Key contributors to this report are listed in appendix IV. In this report, we (1) describe to what extent selected municipalities are incorporating green infrastructure into their efforts to comply with National Pollutant Discharge Elimination System (NPDES) permits and consent decrees that address combined sewer overflows (CSO), and what is known about funding for such efforts; (2) describe what challenges, if any, these municipalities reported facing to incorporate green infrastructure into their efforts to comply with those permits and consent decrees; and (3) examine efforts the Environmental Protection Agency (EPA) is taking to help municipalities use green infrastructure. To describe how selected municipalities are incorporating green infrastructure into their efforts to comply with NPDES permits and consent decrees that address CSOs, what is known about funding for such efforts, and any challenges municipalities reported facing in incorporating green infrastructure into these efforts, we conducted a survey of representatives of 31 municipalities. We selected 20 municipalities that had NPDES permits required of municipalities to discharge stormwater into nearby water bodies, such as creeks, lakes, and rivers. The remaining 11 municipalities had entered into consent decrees with EPA to address CSOs. We restricted our selection of the 31 municipalities to those in the 50 states and Washington, D.C. Although we selected these municipalities at random from a range of geographic locations and a range of sizes, our sample of 31 municipalities cannot be generalized to all municipalities in the United States. We randomly selected the 20 municipalities with NPDES permits from the list of more than 5,000 municipalities that EPA identified in its 1999 rule extending the NPDES program to smaller municipalities. By using the 1999 list, which is almost 18 years old, we enhanced the likelihood that survey respondents would have experience conducting work to comply with their permits. We stratified our sample by size and location. Specifically, we randomly selected 10 municipalities with phase I permits—generally required for municipalities with populations of 100,000 or more—from each of EPA’s 10 regions. We also randomly selected 10 municipalities with phase II permits—generally required for governmental entities with populations of fewer than 100,000 from each of EPA’s 10 regions. Six of the selected municipalities were not available to participate in our survey; in each case, we randomly selected a municipality with the same type of permit from the same EPA region to take its place. Table 2 lists the 20 municipalities with permits that we surveyed, the EPA region in which it is located, and the size of population it serves. We randomly selected the 11 municipalities that have entered into consent decrees with EPA to address CSOs from a list of 36 such municipalities that EPA provided to us. These were municipalities that entered into consent decrees to address CSOs after August 2007. August 2007 is the date of a memorandum in which EPA states, among other things, that it will consider the feasibility of using green infrastructure in its enforcement activities, for example, consent decrees that address CSOs. An analysis of the 36 consent decrees showed that they differed in two characteristics—about half had some mention of green infrastructure in the text of the consent decree and about half were entered into with municipalities in EPA’s Region 5 (the Great Lakes region). The consent decrees were roughly distributed evenly among four groups—with and without mention of green infrastructure and either in or not in Region 5. We stratified our sample of 11 municipalities with consent decrees to be proportionally representative of both of these characteristics. In four instances, a municipality was not available to participate in our survey, in which case we randomly selected another municipality with similar characteristics. We selected these municipalities at random from a range of geographic locations and a range of sizes; however, because of the sample size, among other factors, the results are not generalizable to all municipalities in the United States. Table 3 lists the 11 municipalities with CSO consent decrees that we surveyed, the EPA region in which it is located, and population it serves. The questions we asked municipalities in our survey focused on (1) the extent to which the municipalities were using green infrastructure to comply, at least in part, with requirements of their permits or consent decrees; (2) the amount and source of capital expenditures for green infrastructure to comply, at least in part, with requirements of their permits or consent decrees; and (3) the challenges the municipalities may have experienced in using or considering green infrastructure to comply, at least in part, with requirements of their permits or consent decrees. The time frames for which we asked for information from the survey respondents varied by the questions we asked and whether a municipality was included in our survey because it has an NPDES permit or a consent decree to address CSOs. For questions to municipalities with permits about the extent to which the municipalities were using green infrastructure and questions about the challenges the municipalities may have experienced in using or considering green infrastructure, we asked for information for approximately the 5-year period prior to our survey. For questions to municipalities with consent decrees, we did not specify a time frame. For information on the amount and source of capital expenditure for municipalities with permits and municipalities with consent decrees, we asked survey respondents for the information from the respondents’ last 3 completed fiscal years. We limited these questions to 3 fiscal years to reduce the work burden on the respondents. Our survey questions about the extent to which the municipalities were using green infrastructure included questions about each of the 11 examples of green infrastructure that EPA listed on its website. Our survey questions about the amount and source of capital expenditures for green infrastructure asked about the cost of green infrastructure that was incurred by the permit holder. Seventeen respondents were able to provide us with the information—some provided it during the survey, and others provided it after we concluded the survey. In some instances, the respondents indicated that the expenditure information was an estimate. Our survey questions about challenges asked about the experiences the municipalities had regarding eight aspects of infrastructure development that may have posed challenges to them in using green infrastructure compared to their experiences in using gray infrastructure. The eight aspects are (1) obtaining land for the infrastructure project, (2) designing and engineering the project, (3) developing estimates for capital expenditures, (4) developing estimates for operation and maintenance expenditures, (5) installing the project, (6) the overall cost of the project, (7) confidence in the effectiveness of green infrastructure compared to gray infrastructure, and (8) the political and public opinion of green infrastructure compared to that of gray infrastructure. For each of these eight aspects, we asked municipalities to describe situations in which the aspect encouraged them to install green infrastructure and situations in which the aspect discouraged them from doing so. We examined each of the responses for each of the aspects to identify broad themes, including being unfamiliar with green infrastructure and being committed to using it. To identify the most common themes, we conducted a content analysis in which one analyst classified each response into one or more of the themes and a second analyst independently verified these classifications. For each aspect, we also asked municipalities if, in general, the aspect made green infrastructure usually more challenging than gray infrastructure, usually less challenging, or about the same. We conducted the survey by telephone from November 2016 through April 2017, with one analyst asking the questions, a second analyst documenting the responses electronically, and usually a third analyst taking handwritten notes. We reviewed the responses for accuracy and electronically transferred them into an Excel spreadsheet for analysis. For our survey, we used two questionnaires that were similar in content—one was used with municipalities with NPDES permits and the other was used with municipalities with CSO consent decrees. Both questionnaires are presented in appendix II. To help formulate our survey questions, we reviewed EPA documents and other literature describing green infrastructure and how green infrastructure projects are developed. We then met several times with a public interest group that represents municipal utilities and is familiar with green infrastructure and stormwater. We also pretested the survey with three municipalities and adjusted questions to make them more clear and answerable, as appropriate. To examine efforts EPA is taking to help municipalities use green infrastructure, we reviewed EPA regulations, guidance, and reports, as well as information and tools on EPA’s green infrastructure website. In addition, we interviewed officials from EPA’s Office of Wastewater Management about their ongoing and proposed efforts to encourage the use of green infrastructure. Specifically, we interviewed them about progress toward the items in the agency’s 2013 Strategic Agenda for green infrastructure and efforts they have made to develop a pilot project to collaborate with five communities to incorporate green infrastructure into long-term infrastructure investment plans and permits. We used key considerations on interagency collaboration identified in our prior work to assess the guidance available to the agency to develop collaborative groups. Specifically, our previous work identifies features of collaborative groups, including defining outcomes and ways to track progress, clarifying roles and responsibilities of participating agencies, ensuring that relevant groups participate, and putting guidance and agreements in writing. For all three objectives, we interviewed EPA officials in the agency’s Office of Wastewater Management, the office responsible for managing the Green Infrastructure Program, and Office of Enforcement and Compliance Assurance, as well as representatives from several public interest groups, about the use of green infrastructure by municipalities. We conducted this performance audit from February 2016 to September 2017 in accordance with generally accepted government auditing standards. Those standards require that we plan and perform the audit to obtain sufficient, appropriate evidence to provide a reasonable basis for our findings and conclusions based on our audit objectives. We believe that the evidence obtained provides a reasonable basis for our findings and conclusions based on our audit objectives. GAO used two questionnaires that were similar in content to conduct the survey of municipalities. One questionnaire was used for municipalities with National Pollutant Discharge Elimination System (NPDES) permits, and the other questionnaire was used for municipalities with consent decrees that address combined sewer overflows (CSO). Both questionnaires are presented below. In addition to the contact named above, Susan Iott (Assistant Director), Rodney Bacigalupo, Mark Braza, John W. Delicath, Elizabeth M. Dretsch, Charles Egan, Richard P. Johnson, Ilga Semeiks, and Sarah Veale made key contributions to this report.

Summary: Urban stormwater runoff is a major contributor to pollution in U.S. waters. Municipalities historically managed stormwater with gray infrastructure. In 2007, EPA began encouraging the use of green infrastructure to manage stormwater and reduce the need for gray infrastructure. GAO was asked to examine the use of green infrastructure by municipalities to meet EPA's stormwater requirements. This report (1) describes the extent to which selected municipalities are incorporating, and funding, green infrastructure in stormwater management efforts; (2) describes what challenges, if any, municipalities reported facing in incorporating green infrastructure into stormwater management efforts; and (3) examines efforts EPA is taking to help municipalities use green infrastructure. GAO surveyed two nongeneralizable samples totaling 31 municipalities with stormwater permits or consent decrees for CSOs and interviewed EPA officials to examine EPA efforts to help municipalities use green infrastructure. The municipalities were randomly selected from lists of municipalities that are required to have permits and have consent decrees. Almost all 31 municipalities GAO surveyed reported using green infrastructure to comply with their Clean Water Act permits or combined sewer overflow (CSO) consent decrees. The Environmental Protection Agency (EPA) regulates stormwater pollution under the Clean Water Act, which requires municipalities to obtain permits to discharge stormwater into waterbodies. EPA has also entered into consent decrees with municipalities that have CSOs—events where raw sewage is discharged into waterbodies. Green infrastructure uses natural processes to manage stormwater, such as capturing stormwater so it can seep into soil (see figure). However, of 27 municipalities responding, 15 reported that less than 5 percent of the area subject to their permit or consent decree drained into green infrastructure, with the remaining area draining into gray infrastructure, such as concrete sewers, or directly to waterbodies. Most of the municipalities reported funding green infrastructure with fees and general revenues. Of the 31 municipalities GAO surveyed, 26 reported that green infrastructure was more challenging than gray infrastructure in aspects of infrastructure development, such as developing project operation and maintenance cost estimates. Nevertheless, 25 of these municipalities reported instances where they used green infrastructure even though it was more challenging. Some municipalities reported that they were less familiar with green infrastructure but used it anyway because it performed better or it provided additional benefits, the community wanted to use it, and the municipality saw an opportunity to learn about green infrastructure. EPA provides multiple resources to educate and assist municipalities on the use of green infrastructure. In 2016, the agency launched a pilot project with five municipalities to encourage states, communities, and municipalities to develop long-term stormwater plans to increase their use of green infrastructure. Key to the success of the pilot project is collaboration among many stakeholders from across each community, such as members of the local utility, transportation, and recreation departments, as well as local organizations. GAO has previously identified key considerations, such as documenting agreements on how to collaborate that can benefit collaborative efforts. However, EPA has not yet documented collaborative agreements with pilot stakeholders. EPA could better assure that the stakeholders will successfully develop long-term stormwater plans if it documents how the stakeholders will collaborate. GAO recommends that EPA document agreements, when working with municipalities and other stakeholders, on how they will collaborate when developing long-term stormwater plans. EPA generally agreed with GAO's recommendation and plans to implement it over the next 12 to 18 months.