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Misunderstandings about how operation and maintenance costs for LID practices compare to those of conventional stormwater facilities like detention ponds, oil and grit separators and swales has been one of the significant barriers to their acceptance in the United States and arguably worldwide.  In comparison to conventional stormwater facilities, LID practices have lower life cycle costs, perform better and provide additional benefits, such as improved aesthetics, urban heat island mitigation, and air quality improvement (US EPA, 2013).<ref> United States Environmental Protection Agency (US EPA). 2013a. Maintenance of Low Impact Development: Communities are Easily Managing LID Practices. LID Barrier Busters Fact Sheet Series. https://www.epa.gov/sites/default/files/2015-09/documents/bbfs6maintenance.pdf</ref>  For example, in a controlled field study at the University of New Hampshire Stormwater Center (Houle et al., 2013), maintenance demands and costs were compared over the first 4 years of operation for seven different types of stormwater control measures (SCM), including conventional practices (vegetated swale, wet and dry ponds) and LID/GSI practices (gravel wetland, bioretention, porous asphalt, sand filter). Through estimates of annualized maintenance costs per unit drainage area treated and per unit mass of pollutant removal, they found that LID systems have lower marginal maintenance burdens and higher water quality treatment capabilities than conventional practices like detention ponds and swales. Activities associated with maintaining LID practices were found to be less expensive and more predictable than those for conventional systems.<ref>Houle, J.J., Roseen, R.M., Ballestero, T.P., Puls, T.A., Sherrard, J. 2013. Comparison of Maintenance Cost, Labor Demands and System Performance for LID and Conventional Stormwater Management. Journal of Environmental Engineering. 139(7):932-938. https://scholars.unh.edu/stormwater/3/</ref>   

Misunderstandings about how operation and maintenance costs for LID practices compare to those of conventional stormwater facilities like detention ponds, oil and grit separators and swales has been one of the significant barriers to their acceptance in the United States and arguably worldwide.  In comparison to conventional stormwater facilities, LID practices have lower life cycle costs, perform better and provide additional benefits, such as improved aesthetics, urban heat island mitigation, and air quality improvement (US EPA, 2013).<ref> United States Environmental Protection Agency (US EPA). 2013a. Maintenance of Low Impact Development: Communities are Easily Managing LID Practices. LID Barrier Busters Fact Sheet Series. https://www.epa.gov/sites/default/files/2015-09/documents/bbfs6maintenance.pdf</ref>  For example, in a controlled field study at the University of New Hampshire Stormwater Center (Houle et al., 2013), maintenance demands and costs were compared over the first 4 years of operation for seven different types of stormwater control measures (SCM), including conventional practices (vegetated swale, wet and dry ponds) and LID/GSI practices (gravel wetland, bioretention, porous asphalt, sand filter). Through estimates of annualized maintenance costs per unit drainage area treated and per unit mass of pollutant removal, they found that LID systems have lower marginal maintenance burdens and higher water quality treatment capabilities than conventional practices like detention ponds and swales. Activities associated with maintaining LID practices were found to be less expensive and more predictable than those for conventional systems.<ref>Houle, J.J., Roseen, R.M., Ballestero, T.P., Puls, T.A., Sherrard, J. 2013. Comparison of Maintenance Cost, Labor Demands and System Performance for LID and Conventional Stormwater Management. Journal of Environmental Engineering. 139(7):932-938. https://scholars.unh.edu/stormwater/3/</ref>