Rain barrels
Rain barrels collect and store rainwater from rooftops that would otherwise flow to storm drains and streams. Rain barrels can be purchased ready-made or created from off-the-shelf items such as a large barrel, vinyl hose, PVC couplings, and screen grates. Rain barrels are typically used in single-family residential settings; cisterns or other storage units collect or store rainwater from larger buildings such as commercial, industrial, or multi-family buildings (US EPA-Rain barrels). Rain barrels or rainwater harvesting programs can be implemented by individuals or supported by city or state initiatives. Many cities combine rain barrels, green roofs, bioretention cells, and permeable pavement infrastructure to create sustainable urban drainage systems (SUDS) that help absorb and control stormwater (Joshi 2021). Rain barrels are a form of green infrastructure that can replace or supplement inadequate gray infrastructure (e.g., gutters, pipes, and tunnels) that would otherwise convey stormwater to water treatment facilities or directly to nearby bodies of water (US EPA-Green infrastructure). Rain barrels and rainwater harvesting initiatives can be supported by education about stormwater management, water conservation, and homeowner water resource management (Bakacs 2013).
What could this strategy improve?
Expected Benefits
Our evidence rating is based on the likelihood of achieving these outcomes:
- Reduced run-off
Potential Benefits
Our evidence rating is not based on these outcomes, but these benefits may also be possible:
- Increased water conservation
- Reduced water pollution
- Reduced energy use
What does the research say about effectiveness? -+
There is some evidence that rain barrels reduce stormwater run-off, which is a major cause of flooding, erosion, and water pollution, especially in urban areas (Braga 2018, Semaan 2021, Joshi 2021, Roman 2017, Ahiablame 2013, Ahiablame 2016, Litofsky 2014, Liu 2015, Di Vittorio 2015, Martin 2015, Rostad 2016, Wright 2016). Rain barrels are also a suggested strategy to increase water conservation, reduce water pollution (US EPA-Rain barrels, CDC-Rainwater, Guo 2007, Shuster 2013), and reduce water scarcity issues (Palawat 2023, Semaan 2021, Ghimire 2019a). Additional evidence is needed to confirm effects, particularly when implemented on a larger community scale.
Rainwater harvesting, implemented throughout a community with either decentralized or centralized installations, can reduce run-off, increase the resilience of traditional stormwater infrastructure, and reduce flooding and property damage (Semaan 2021). Stormwater run-off in urban areas with combined sewer systems is a serious water pollution concern since heavy rainfall can overload combined systems and cause untreated wastewater and stormwater to discharge directly into nearby bodies of water (Braga 2018). Large scale rainwater harvesting has the potential to manage stormwater and reduce water pollution more effectively than conventional stormwater infrastructure, especially in areas where stormwater and sewer water systems are combined (Braga 2018, Roman 2017). A model analysis of sustainable urban drainage systems (SUDS) that includes rain barrels and green roofs suggests that SUDS can reduce stormwater run-off and sewer overflows (Joshi 2021).
Rainwater harvesting and gray water reuse through rain barrel systems can reduce consumption of potable water and generation of wastewater, which may lead to significant energy savings for national and local utilities (Malinowski 2015). Using harvested rainwater for irrigation and agricultural applications instead of municipal water supplies can reduce energy use, greenhouse gas emissions, and water scarcity issues (Ghimire 2019a, Parece 2016). An Oregon-based study suggests that rain cisterns combined with underground storage tanks can effectively store rainwater from the wet season for use during dry summer months, reducing demand for municipal, treated water. Climate change and droughts have created water scarcity issues in the Pacific Northwest, which rainwater harvesting may alleviate (Olsen 2017).
Rain barrel systems’ benefits are limited by the capacity of the barrel or storage unit. Broad implementation throughout a region or efforts to combine rain barrels with additional stormwater management techniques and tools, such as porous pavement, green roofs, or rain gardens, can increase effects (Joshi 2021, Braga 2018, Jennings 2013, Ahiablame 2013, Martin-Mikle 2015, Di Vittorio 2015). Rain barrels are one of the most common types of infrastructure used in SUDS and are adaptable for small-, medium-, or large-scale use (Ferrans 2022).
Experts caution that harvested rainwater can become contaminated with heavy metals such as lead and zinc, as well as microbial pathogens, through contact with roofs and should not be considered potable or safe for human consumption without treatment (Deng 2021, Palawat 2023, Hamilton 2018a, Hamilton 2017). Rainwater harvesting is a sustainable source of water for crop irrigation in urban agriculture settings; however, potential pollutants in harvested rainwater can impact crop, soil, and human health, therefore water quality monitoring and treatments are suggested to prevent such issues (Deng 2021). Studies suggest that the risk of contamination from metals is low, especially when harvested rainwater is intended for non-potable uses, including gardening, car washing, toilet flushing, clothes washing, etc., while the risk of exposure to pathogens may be higher if rainwater is aerosolized during use or if produce irrigated with rainwater is consumed raw (Hamilton 2018a). An Australia-based study suggests that these risks are greatest for children and people with immune compromising conditions (Hamilton 2017).
Take-up of green technology (e.g., rain barrels) is associated with owner occupancy, higher incomes, and sustainability-conscious individuals (Ando 2011); gardeners are the most frequent adopters. Cost and lack of knowledge can be barriers to adoption (Gao 2016). Regular re-examination and updates to plumbing codes and regulations can support adoption of new practices such as rainwater harvesting and gray water reuse (Novak 2015).
Rain barrel systems are relatively simple and inexpensive to construct and install; costs range from $4-11 per cubic foot of stormwater storage capacity (Wright 2016). Rain barrels save most homeowners about 1,300 gallons of water during peak summer months, reducing demand for treated tap water and water bills for participating homeowners (US EPA-Rain barrels).
Rain barrels are especially cost-effective for outdoor water use (Dallman 2021, Dallman 2016, Jha 2015). Overall, rain barrel systems generate positive net benefits for homeowners, water suppliers, and society (Dallman 2021, Logan 2014), with even larger net benefits for stormwater management systems that combine rain barrels with other green infrastructure (Mitchell 2016). Rain barrels and other SUDS infrastructure are cost-effective for cities as tools to reduce sewer overflows (Joshi 2021). Modelling studies suggest rain barrels can also cost-effectively increase water supply reliability and meet water demand in rural areas, especially when consumers are offered financial incentives to promote adoption (Gonela 2020).
How could this strategy advance health equity? This strategy is rated potential to decrease disparities: suggested by expert opinion. -+
Rain barrels are one of several types of green infrastructure recommended to help manage stormwater run-off, which can reduce water pollution and flooding in urban areas (US EPA-Green infrastructure, Semaan 2021). Efforts to improve stormwater management through green infrastructure initiatives are a suggested strategy to reduce disparities by race and income in exposure to flood risk and health dangers from untreated stormwater (PI-Yanez 2021). Communities of color and those with lower incomes experience greater flooding risks from inadequate or outdated stormwater infrastructure and risks are increasing with climate change (PI-Yanez 2021). Families can also be exposed to pathogens that cause illness, as well as pollution that includes industrial chemicals, if low quality stormwater and sewer infrastructure leads to indoor flooding (Urban-Fedorowicz 2020). Experts suggest that rain barrels and communal rainwater harvesting systems have the potential to reduce flooding and property damage; to reduce the demand for municipal water, which can in turn reduce households’ water bills; and to increase the resilience of water and stormwater infrastructure, as climate change affects rainfall patterns and storm intensity (Semaan 2021).
Climate change is expected to intensify both drought and heavy rain events for many parts of the country (PI-Yanez 2021). Model analysis suggests that rainwater harvesting has the potential to reduce water scarcity issues in geographically diverse areas across the U.S. (Semaan 2021). However, experts caution that rain barrels and rainwater harvesting initiatives should be implemented alongside efforts to promote equitable water access, especially in arid areas, to avoid increasing disparities in water access by income level, based on who can afford to install rain barrels (Elder 2019).
What is the relevant historical background? -+
The practice of rainwater harvesting has been around for thousands of years. Rain barrels were common in the U.S. throughout the 1800s, but their use declined after World War II with the rise of public water utilities (RBD-Blog 2014). In recent decades, concerns about aging water infrastructure across the U.S. have grown (BPC-Water infrastructure 2016), along with awareness that the government and public water utilities have substantially underinvested in water and wastewater infrastructure in communities of color and communities with low incomes. Experts suggest that environmental justice principles require helping these communities build critical new infrastructure to fully meet their needs for potable water, stormwater, and wastewater systems (Coursen 2021).
More people are living in urban areas than in previous decades, with 8 in 10 individuals predicted to live in cities by 2050 (Gianfredi 2021). Urban areas generally contain much more impervious surface coverage that generates stormwater run-off than rural or suburban areas (Kuruppu 2019). In the 1990s, local planners and others began to shift their focus away from gray infrastructure (e.g.,concrete pipes, culverts, and spillways) to manage stormwater and towards green infrastructure, which includes treatments to absorb or capture rainwater as a way to reduce the flooding severity of storm events and to reduce the amount of pollutants entering ground and surface waters from excess stormwater (Urban-Fedorowicz 2020, Kuruppu 2019). In recent years, there has been a renewed interest in rain barrels and rainwater harvesting as tools to impact potable, stormwater, and wastewater systems and reduce demand for municipal water services (Semaan 2021, US EPA-Green infrastructure).
Historically, systems for drinking water, groundwater, stormwater, and wastewater were governed by different U.S. agencies; however, experts recommend increased coordination to understand the full costs and benefits of policy and infrastructure decisions (PI-Yanez 2021).
Equity Considerations -+
- Where are rain barrels being installed in your community? Have broader rainwater harvesting initiatives been implemented in your region or state? If so, where?
- Who is making decisions about rainwater harvesting initiatives and stormwater management in your area? What are the priorities of these projects (e.g., reduce demand for municipal water, reduce flood risk, increase water access, etc.)?
- How are communities paying for rain barrels and rainwater harvesting projects? What funds are available to support rain barrels for homeowners with lower incomes? For rental properties? For buildings with affordable housing units?
- What outreach is happening in communities with new installations as a way to increase understanding of stormwater management systems’ functions and maintenance, and to solicit input for additional green infrastructure projects?
Implementation Examples -+
Seventeen states and Washington, D.C. have state regulations that encourage or support rainwater harvesting; many also have state or local incentives available to encourage rain barrel use, as in Arizona, California, Georgia, New Mexico, North Carolina, Texas, and Washington. Twenty-one states have no specific regulations but generally encourage rainwater harvesting, usually by providing technical resources to support adoption. In ten states there are no regulations or policies specific to rainwater harvesting; however, it is not illegal. In Colorado and Nevada, there are prohibitions or capacity limits in place and only a very limited amount of residential rainwater harvesting is allowed; other larger scale applications are not permitted (US DOE-Rainwater regulations map).
Cities and counties across the country have rain barrel programs that give away rain barrels or subsidize purchases; examples include New York City, Philadelphia, Chicago, Syracuse, and Cuyahoga County, Ohio (NYC DEP-Rain barrels, Philadelphia-Rain barrels, Chicago-Rain barrels, Syracuse-STR, Cuyahoga-Rain barrels). Other cities and counties provide information to encourage residential rain barrel and cistern use, as in Los Angeles, or offer rain barrel making workshops, as in Fairfax County, Virginia (LASAN-Rain barrels, Fairfax-Rain barrels). In Chicago, city agency partners propose repurposing an abandoned potable water tunnel into a 3-mile long rain barrel to increase capacity; it has a potential stormwater storage volume of 6 million gallons (Gage 2016).
The Bullitt Center in Seattle is a commercial building designed and built with many sustainable and environmentally conscious features, including rainwater harvesting. Captured rainwater is used exclusively to meet all of the building’s needs; the center includes an approved potable water system that treats and stores rainwater in a 500-gallon tank until it is consumed. There is also a 56,000-gallon cistern for gray water reuse, which returns any excess gray water to the soil (Bullitt-Rainwater).
Implementation Resources -+
Greene 2015 - Greene B, Mesner N, Brain R. Fact sheet: Rain barrels in Utah. Utah State University Extension Sustainability; Paper 747. 2015.
Harvest H2O - HarvestH2O. Rainwater harvesting: Frequently asked questions.
Penn State Ext-Fetter 2021 - Fetter JR. Stormwater basics: Ready-to-use educational toolkit for stormwater management. Penn State Extension. April 8, 2021.
US DOE-Rainwater regulations map - U.S. Department of Energy (U.S. DOE), Federal Energy Management Program. Rainwater harvesting regulations map.
US EPA-Rain barrels - U.S. Environmental Protection Agency (U.S. EPA). Rain barrels.
Citations -+
* Journal subscription may be required for access.
Ahiablame 2013* - Ahiablame LM, Engel BA, Chaubey I. Effectiveness of low impact development practices in two urbanized watersheds: Retrofitting with rain barrel/cistern and porous pavement. Journal of Environmental Management. 2013;119:151-61.
Ahiablame 2016* - Ahiablame L, Shakya R. Modeling flood reduction effects of low impact development at a watershed scale. Journal of Environmental Management. 2016;171:81-91.
Ando 2011 - Ando AW, Freitas LPC. Consumer demand for green stormwater management technology in an urban setting: The case of Chicago rain barrels. Water Resources Research. 2011;47:1-11.
Bakacs 2013 - Bakacs ME, Hill C, Mellor S. Rain barrels: A catalyst for change. Journal of Extension. 2013;51(3):1-10.
BPC-Water infrastructure 2016 - Bipartisan Policy Center (BPC). America's aging water infrastructure. 2016.
Braga 2018 - Braga A, O’Grady H, Dabak T, Lane C. Performance of two advanced rainwater harvesting systems in Washington, D.C. Water (Switzerland). 2018;10(5):667.
Bullitt-Rainwater - Bullitt Center. Building features: Rainwater harvesting.
CDC-Rainwater - Centers for Disease Control and Prevention (CDC). Drinking water: Rainwater collection.
Chicago-Rain barrels - Metropolitan Water Reclamation District of Greater Chicago. Rain barrels.
Coursen 2021 - Coursen DF. Water infrastructure - the unmet needs of low-income communities. The Hill; Energy and Environment Opinion. February 3, 2021.
Cuyahoga-Rain barrels - Cuyahoga Soil and Water Conservation District. Rain barrels.
Dallman 2016* - Dallman S, Chaudhry AM, Muleta MK, Lee J. The value of rain: Benefit-cost analysis of rainwater harvesting systems. Water Resources Management. 2016;30(12):4415-4428.
Dallman 2021* - Dallman S, Chaudhry AM, Muleta MK, Lee J. Is rainwater harvesting worthwhile? A benefit–cost analysis. Journal of Water Resources Planning and Management. 2021;147(4):04021011.
Deng 2021 - Deng Y. Pollution in rainwater harvesting: A challenge for sustainability and resilience of urban agriculture. Journal of Hazardous Materials Letters. 2021;2:100037.
Di Vittorio 2015 - Di Vittorio D, Ahiablame L. Spatial translation and scaling up of low impact development designs in an urban watershed. Journal of Water Management Modeling. 2015:1-9.
Elder 2019* - Elder AD, Gerlak AK. Interrogating rainwater harvesting as Do-It-Yourself (DIY) Urbanism. Geoforum. 2019;104:46-54.
Fairfax-Rain barrels - Fairfax County Virginia. Rain barrel workshops.
Ferrans 2022 - Ferrans P, Torres MN, Temprano J, Rodríguez Sánchez JP. Sustainable Urban Drainage System (SUDS) modeling supporting decision-making: A systematic quantitative review. Science of the Total Environment. 2022;806(2):150447.
Gage 2016* - Gage J, Yurik J, Martin A. The world’s largest rain barrel: Chicago considers repurposing an abandoned tunnel into a massive rooftop rainwater collection system. WE&T Magazine. 2016.
Gao 2016* - Gao Y, Babin N, Turner AJ, et al. Understanding urban-suburban adoption and maintenance of rain barrels. Landscape and Urban Planning. 2016;153:99-110.
Ghimire 2019a - Ghimire SR, Johnston JM. Sustainability assessment of agricultural rainwater harvesting: Evaluation of alternative crop types and irrigation practices. PLoS ONE. 2019;14(5):e0216452.
Gianfredi 2021 - Gianfredi V, Buffoli M, Rebecchi A, et al. Association between urban greenspace and health: A systematic review of literature. International Journal of Environmental Research and Public Health. 2021;18(10):5137.
Gonela 2020* - Gonela V, Altman B, Zhang J, et al. Decentralized rainwater harvesting program for rural cities considering tax incentive schemes under stakeholder interests and purchasing power restrictions. Journal of Cleaner Production. 2020;252:119843.
Guo 2007* - Guo Y, Baetz BW. Sizing of rainwater storage units for green building applications. Journal of Hydrologic Engineering. 2007;12(2):197-205.
Hamilton 2017* - Hamilton KA, Ahmed W, Toze S, Haas CN. Human health risks for Legionella and Mycobacterium avium complex (MAC) from potable and non-potable uses of roof-harvested rainwater. Water Research. 2017;119:288-303.
Hamilton 2018a - Hamilton KA, Parrish K, Ahmed W, Haas CN. Assessment of water quality in roof-harvested rainwater barrels in Greater Philadelphia. Water (Switzerland). 2018;10(2):92.
Jennings 2013* - Jennings AA, Adeel AA, Hopkins A, Litofsky AL, Wellstead SW. Rain barrel: Urban garden stormwater management performance. Journal of Environmental Engineering. 2013;(139):757-765.
Jha 2015 - Jha MK, Shah N. Evaluating rainwater harvesting system for school buildings. American Journal of Environmental Sciences. 2015;11(4):256-261.
Joshi 2021 - Joshi P, Leitão JP, Maurer M, Bach PM. Not all SuDS are created equal: Impact of different approaches on combined sewer overflows. Water Research. 2021;191:116780.
Kuruppu 2019* - Kuruppu U, Rahman A, Rahman MA. Permeable pavement as a stormwater best management practice: A review and discussion. Environmental Earth Sciences. 2019;78:327.
La Crosse-Stormwater - La Crosse, Wisconsin. Stormwater utility: Stormwater credits & forms.
LASAN-Rain barrels - City of Los Angeles, LA Sanitation & Environment (LASAN). Watershed actions: Harvest rainwater: Where to get a rain barrel and rain barrel FAQs.
Litofsky 2014* - Litofsky ALE, Jennings AA. Evaluating rain barrel storm water management effectiveness across climatography zones of the United States. Journal of Environmental Engineering. 2014;(140):1-10.
Liu 2015* - Liu Y, Ahiablame LM, Bralts VF, Engel BA. Enhancing a rainfall-runoff model to assess the impacts of BMPs and LID practices on storm runoff. Journal of Environmental Management. 2015;147:12-23.
Logan 2014* - Logan J. Using a spreadsheet to model rain barrel efficiency and cost benefit for homeowners. HortTechnology. 2014;24(1):156-158.
Malinowski 2015* - Malinowski PA, Stillwell AS, Wu JS, Schwarz PM. Energy-water nexus: Potential energy savings and implications for sustainable integrated water management in urban areas from rainwater harvesting and gray-water reuse. Journal of Water Resources Planning and Management. 2015;141(12):A4015003.
Martin 2015* - Martin AR, Ahiablame LM, Engel BA. Modeling low impact development in two Chicago communities. Environmental Science: Water Research & Technology. 2015;1(6):855-864.
Martin-Mikle 2015 - Martin-Mikle CJ, de Beurs KM, Julian JP, Mayer PM. Identifying priority sites for low impact development (LID) in a mixed-use watershed. Landscape and Urban Planning. 2015;140:29-41.
Mitchell 2016* - Mitchell K, Ladouceur A, Liu R, Coffman R. Triple bottom line cost-benefit analysis of green infrastructure in Norman, Oklahoma. The International Journal of the Constructed Environment. 2016;7(4):1-15.
Novak 2015 - Novak PJ, Arnold WA, Henningsgaard B, et al. Innovation promoted by regulatory flexibility. Environmental Science & Technology. 2015;49(24):13908-13909.
NYC DEP-Rain barrels - New York City Department of Environmental Protection (NYC DEP). Rain barrel giveaway program.
Olsen 2017 - Olsen C, Kowalewski A, Gould M, Lambrinos J. Evaluating two rainwater harvesting systems in an urban setting in Oregon’s Willamette Valley. Journal of Green Building. 2017;12(1):1-10.
Palawat 2023* - Palawat K, Root RA, Cortez LI, et al. Patterns of contamination and burden of lead and arsenic in rooftop harvested rainwater collected in Arizona environmental justice communities. Journal of Environmental Management. 2023;337:117747.
Parece 2016* - Parece TE, Lumpkin M, Campbell JB. Irrigating urban agriculture with harvested rainwater: Case study in Roanoke, Virginia, USA. In: Younos T, Parece TE, eds. Sustainable Water Management in Urban Environments. Vol 47. Switzerland: Springer International Publishing; 2016:235-263.
Philadelphia-Rain barrels - Philadelphia Water Department. Rain barrel workshops.
PI-Yanez 2021 - Yañez E, Bennett R, Bruins E, Aboelata MJ. A time of opportunity: Water, health, and equity in the Los Angeles region. Case statement prepared for the Water Foundation. Oakland, CA: Prevention Institute (PI); 2021.
RBD-Blog 2014 - The Rain Barrel Depot (RBD). Blog: The rain barrel: Some things old, become new again. August 7, 2014.
River Falls-Rain barrels - River Falls Wisconsin. Rain barrels.
Roman 2017 - Roman D, Braga A, Shetty N, Culligan P. Design and modeling of an adaptively controlled rainwater harvesting system. Water (Switzerland). 2017;9(12):974.
Rostad 2016* - Rostad N, Foti R, Montalto FA. Harvesting rooftop runoff to flush toilets: Drawing conclusions from four major U.S. cities. Resources, Conservation and Recycling. 2016;108:97-106.
Semaan 2021* - Semaan M, Day SD, Garvin M, Ramakrishnan N, Pearce A. Distributed rainwater harvesting: Novel approach to rainwater harvesting systems for single-family households. Journal of Water Resources Planning and Management. 2021;147(10):04021061.
Shuster 2013* - Shuster WD, Lye D, De La Cruz A, et al. Assessment of residential rain barrel water quality and use in Cincinnati, Ohio. Journal of the American Water Resources Association. 2013;49(4):753-765.
Syracuse-STR - City of Syracuse, Onondaga County, New York. Save the Rain (STR) rain barrel program.
Urban-Fedorowicz 2020 - Fedorowicz M, Schilling J, Bramhall E, et al. Leveraging the built environment for health equity: Promising interventions for small and medium-size cities. Washington, D.C.: Urban Institute; 2020.
US DOE-Rainwater regulations map - U.S. Department of Energy (U.S. DOE), Federal Energy Management Program. Rainwater harvesting regulations map.
US EPA-Green infrastructure - U.S. Environmental Protection Agency (U.S. EPA). What is green infrastructure?
US EPA-Rain barrels - U.S. Environmental Protection Agency (U.S. EPA). Rain barrels.
Wright 2016* - Wright TJ, Liu Y, Carroll NJ, Ahiablame LM, Engel BA. Retrofitting LID practices into existing neighborhoods: Is it worth it? Environmental Management. 2016;57(4):856-867.