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 usually 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 barrel or rainwater harvesting programs can be implemented by individuals or supported by city or state initiatives. Such initiatives are frequently combined with other green infrastructure projects such as rain gardens and permeable pavement, and with education about stormwater management, water conservation, and homeowner water resource management2.
Expected Beneficial Outcomes (Rated)
Other Potential Beneficial Outcomes
Increased water conservation
Reduced water pollution
Reduced energy use
Evidence of 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 areas3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13. Rain barrels are also a suggested strategy to increase water conservation and reduce water pollution1, 14, 15, 16. Additional evidence is needed to confirm effects.
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 utilities17. A Virginia-based study suggests irrigating urban agriculture sites with rainwater harvested in rain barrels instead of municipal water supplies can reduce run-off and greenhouse gas emissions18.
Rainwater harvesting can reduce stormwater run-off volume up to 20% in semiarid regions, and less in regions that receive greater amounts of rainfall10. Rain barrels’ effects vary by region in the United States; the largest run-off reductions occur in the southwest, and the smallest in the southeast5.
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 or rain gardens, can increase effects8, 9, 3, 19.
Take-up of green technology (e.g., rain barrels) is associated with owner occupancy, higher incomes, and sustainably-minded individuals20; gardeners are the most frequent adopters. Cost and lack of knowledge can be barriers to adoption21. Regular re-examination and updates to plumbing codes and regulations can support adoption of new practices such as rainwater harvesting and gray water reuse22.
Rain barrel systems are relatively simple and inexpensive to construct and install; costs range from $4-11 per cubic foot of stormwater storage capacity13. 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 use23, 24. Overall, rain barrel systems generate positive net benefits for homeowners and society25, with even larger net benefits for stormwater management systems that combine rain barrels with other green infrastructure26.
Impact on Disparities
Sixteen states - Arizona, Arkansas, California, Colorado, Hawaii, Illinois, Nevada, North Carolina, Ohio, Oklahoma, Oregon, Rhode Island, Texas, Utah, Virginia, and Washington - and the US Virgin Islands have rainwater harvesting and gray water laws and programs. Many states have regulations that limit the use of harvested rainwater to outdoor, irrigation, and other water conservation uses, and prohibit potable water uses. Other states (e.g., Texas and Ohio) have comprehensive legislation that supports rainwater harvesting for all purposes, including potable water use. A few states, particularly in the West where water resources are scarce, have prohibitions or capacity limits for rainwater harvesting, as in Colorado and Nevada27.
Cities and municipalities across the country have rain barrel programs that give away rain barrels or subsidize purchases, for example, New York City28, Philadelphia29, Chicago30, Syracuse31, and Cleveland32. Other cities and counties provide information to encourage residential rain barrel and cistern use, as in Los Angeles33, or offer rain barrel making workshops, as in Fairfax County, Virginia34. 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 gallons35.
DIY-Rain barrels - Do It Yourself Network (DIY). How to build a rainwater diverter and rain barrel.
Instructables-Rain barrels - Instructables. Shape what you make: Rain barrels.
Harvest H2O - HarvestH2O. Rainwater harvesting: Frequently asked questions.
Rainwater Plus - Rainwater+. A new tool for urban rainwater runoff assessment and management.
Greene 2015 - Greene B, Mesner N, Brain R. Fact sheet: Rain Barrels in Utah. Utah State University Extension Sustainability; Paper 747. 2015.
* Journal subscription may be required for access.
1 US EPA-Rain barrels - US Environmental Protection Agency (US EPA). Rain barrels.
2 Bakacs 2013 - Bakacs ME, Hill C, Mellor S. Rain barrels: A catalyst for change. Journal of Extension. 2013;51(3):1-10.
3 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.
4 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.
5 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):04014009-1-10.
6 Aad 2010* - Aad MPA, Suidan MT, Shuster WD. Modeling techniques of best management practices: Rain barrels and rain gardens using EPA SWMM-5. Journal of Hydrologic Engineering. 2010;(15):434-443.
7 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.
8 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.
9 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.
10 Steffen 2013* - Steffen J, Jensen M, Pomeroy CA, Burian SJ. Water supply and stormwater management benefits of residential rainwater harvesting in U.S. cities. Journal of the American Water Resources Association. 2013;49(4):810-824.
11 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.
12 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.
13 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.
14 CDC-Rainwater - Centers for Disease Control and Prevention (CDC). Drinking water: Rainwater collection.
15 Guo 2007* - Guo Y, Baetz BW. Sizing of rainwater storage units for green building applications. Journal of Hydrologic Engineering. 2007;12(2):197-205.
16 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.
17 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.
18 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.
19 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.
20 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.
21 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.
22 Novak 2015 - Novak PJ, Arnold WA, Henningsgaard B, et al. Innovation promoted by regulatory flexibility. Environmental Science & Technology. 2015;49(24):13908-13909.
23 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.
24 Jha 2015 - Jha MK, Shah N. Evaluating rainwater harvesting system for school buildings. American Journal of Environmental Sciences. 2015;11(4):256-261.
25 Logan 2014* - Logan J. Using a spreadsheet to model rain barrel efficiency and cost benefit for homeowners. HortTechnology. 2014;24(1):156-158.
26 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.
27 NCSL-Rainwater legislation 2017 - National Conference of State Legislatures (NCSL). State rainwater harvesting laws and legislation. 2017.
28 NYC DEP-Rain barrels - New York City Department of Environmental Protection (NYC DEP). 2013 Rain barrel giveaway program.
29 Philadelphia-Rain barrels - Philadelphia Water Department. Rain barrel workshops.
30 Chicago-Rain barrels - Metropolitan Water Reclamation District of Greater Chicago. Rain barrels.
31 Syracuse-STR - City of Syracuse, Onondaga County, New York. Save the Rain (STR) rain barrel program.
32 Cleveland-Rain barrels - City of Cleveland. Water quality and efficiency: Rain barrel program.
33 LA Stormwater-Rain barrels - City of Los Angeles Stormwater Program. Rain barrels and cisterns.
34 Fairfax-Rain barrels - Fairfax County Virginia. Rain barrel workshops.
35 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.
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