Rain barrels

Evidence Rating  
Evidence rating: Some Evidence

Strategies with this rating are likely to work, but further research is needed to confirm effects. These strategies have been tested more than once and results trend positive overall.

Disparity Rating  
Disparity rating: Potential to decrease disparities

Strategies with this rating have the potential to decrease or eliminate disparities between subgroups. Rating is suggested by evidence, expert opinion or strategy design.

Health Factors  
Date last updated

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 buildings1. 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 stormwater2. 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 water3. Rain barrels and rainwater harvesting initiatives can be supported by education about stormwater management, water conservation, and homeowner water resource management4.

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 areas2, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15. Rain barrels are also a suggested strategy to increase water conservation, reduce water pollution1, 16, 17, 18, and reduce water scarcity issues6, 19, 20. 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 damage6. 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 water5. 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 combined5, 7. 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 overflows2.

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 utilities21. Using harvested rainwater for irrigation and agricultural applications instead of municipal water supplies can reduce energy use, greenhouse gas emissions, and water scarcity issues20, 22. 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 alleviate23.

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 effects2, 5, 8, 12, 24, 25. Rain barrels are one of the most common types of infrastructure used in SUDS and are adaptable for small-, medium-, or large-scale use26.

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 treatment19, 27, 28, 29. 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 issues27. 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 raw28. An Australia-based study suggests that these risks are greatest for children and people with immune compromising conditions29.

Take-up of green technology (e.g., rain barrels) is associated with owner occupancy, higher incomes, and sustainability-conscious individuals30; gardeners are the most frequent adopters. Cost and lack of knowledge can be barriers to adoption31. Regular re-examination and updates to plumbing codes and regulations can support adoption of new practices such as rainwater harvesting and gray water reuse32.

Rain barrel systems are relatively simple and inexpensive to construct and install; costs range from $4-11 per cubic foot of stormwater storage capacity15. 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 homeowners1.

Rain barrels are especially cost-effective for outdoor water use33, 34, 35. Overall, rain barrel systems generate positive net benefits for homeowners, water suppliers, and society33, 36, with even larger net benefits for stormwater management systems that combine rain barrels with other green infrastructure37. Rain barrels and other SUDS infrastructure are cost-effective for cities as tools to reduce sewer overflows2. 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 adoption38.

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 areas3, 6. 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 stormwater49. Communities of color and those with lower incomes experience greater flooding risks from inadequate or outdated stormwater infrastructure and risks are increasing with climate change49. 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 flooding50. 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 intensity6.

Climate change is expected to intensify both drought and heavy rain events for many parts of the country49. Model analysis suggests that rainwater harvesting has the potential to reduce water scarcity issues in geographically diverse areas across the U.S.6. 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 barrels51.

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 utilities52. In recent decades, concerns about aging water infrastructure across the U.S. have grown53, 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 systems54.

More people are living in urban areas than in previous decades, with 8 in 10 individuals predicted to live in cities by 205055. Urban areas generally contain much more impervious surface coverage that generates stormwater run-off than rural or suburban areas56. 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 stormwater50, 56. 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 services3, 6.

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 decisions49.

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 permitted39.

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, Ohio40, 41, 42, 43, 44. 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, Virginia45, 46. 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 gallons47.

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 soil48.

Implementation Resources

Resources with a focus on equity.

US DOE-Rainwater regulations map - U.S. Department of Energy (U.S. DOE), Federal Energy Management Program. Rainwater harvesting regulations map.

Harvest H2O - HarvestH2O. Rainwater harvesting: Frequently asked questions.

Greene 2015 - Greene B, Mesner N, Brain R. Fact sheet: Rain barrels in Utah. Utah State University Extension Sustainability; Paper 747. 2015.

US EPA-Rain barrels - U.S. Environmental Protection Agency (U.S. EPA). Rain barrels.

Penn State Ext-Fetter 2021 - Fetter JR. Stormwater basics: Ready-to-use educational toolkit for stormwater management. Penn State Extension. April 8, 2021.


* Journal subscription may be required for access.

1 US EPA-Rain barrels - U.S. Environmental Protection Agency (U.S. EPA). Rain barrels.

2 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.

3 US EPA-Green infrastructure - U.S. Environmental Protection Agency (U.S. EPA). What is green infrastructure?

4 Bakacs 2013 - Bakacs ME, Hill C, Mellor S. Rain barrels: A catalyst for change. Journal of Extension. 2013;51(3):1-10.

5 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.

6 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.

7 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.

8 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.

9 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.

10 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.

11 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.

12 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.

13 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.

14 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.

15 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.

16 CDC-Rainwater - Centers for Disease Control and Prevention (CDC). Drinking water: Rainwater collection.

17 Guo 2007 - Guo Y, Baetz BW. Sizing of rainwater storage units for green building applications. Journal of Hydrologic Engineering. 2007;12(2):197-205.

18 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.

19 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.

20 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.

21 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.

22 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.

23 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.

24 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.

25 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.

26 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.

27 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.

28 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.

29 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.

30 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.

31 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.

32 Novak 2015 - Novak PJ, Arnold WA, Henningsgaard B, et al. Innovation promoted by regulatory flexibility. Environmental Science & Technology. 2015;49(24):13908-13909.

33 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.

34 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.

35 Jha 2015 - Jha MK, Shah N. Evaluating rainwater harvesting system for school buildings. American Journal of Environmental Sciences. 2015;11(4):256-261.

36 Logan 2014 - Logan J. Using a spreadsheet to model rain barrel efficiency and cost benefit for homeowners. HortTechnology. 2014;24(1):156-158.

37 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.

38 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.

39 US DOE-Rainwater regulations map - U.S. Department of Energy (U.S. DOE), Federal Energy Management Program. Rainwater harvesting regulations map.

40 NYC DEP-Rain barrels - New York City Department of Environmental Protection (NYC DEP). Rain barrel giveaway program.

41 Philadelphia-Rain barrels - Philadelphia Water Department. Rain barrel workshops.

42 Chicago-Rain barrels - Metropolitan Water Reclamation District of Greater Chicago. Rain barrels.

43 Syracuse-STR - City of Syracuse, Onondaga County, New York. Save the Rain (STR) rain barrel program.

44 Cuyahoga-Rain barrels - Cuyahoga Soil and Water Conservation District. Rain barrels.

45 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.

46 Fairfax-Rain barrels - Fairfax County Virginia. Rain barrel workshops.

47 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.

48 Bullitt-Rainwater - Bullitt Center. Building features: Rainwater harvesting.

49 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.

50 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.

51 Elder 2019 - Elder AD, Gerlak AK. Interrogating rainwater harvesting as Do-It-Yourself (DIY) Urbanism. Geoforum. 2019;104:46-54.

52 RBD-Blog 2014 - The Rain Barrel Depot (RBD). Blog: The rain barrel: Some things old, become new again. August 7, 2014.

53 BPC-Water infrastructure 2016 - Bipartisan Policy Center (BPC). America's aging water infrastructure. 2016.

54 Coursen 2021 - Coursen DF. Water infrastructure - the unmet needs of low-income communities. The Hill; Energy and Environment Opinion. February 3, 2021.

55 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.

56 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.