30 SECONDS WITH YOUR MAYOR
Building Codes & Rainwater Harvesting
By the year 2050, the worldwide availability of freshwater will have decreased by a third as a
result of global warming, population growth, and wasteful habits. 1 As a water conservation
strategy, rainwater harvesting conserves water through the collection and storage of water for
human use, and is easily implemented, replicable, and regulated. Another benefit of rainwater
harvesting is a reduction in stormwater runoff and erosion. Building codes with provisions for
rainwater harvesting promote water conservation and site management on a community scale.
Could include local data on stormwater runoff rates and fees or water conservation statistics.
PROPOSED ORDINANCE
If not explicitly prohibited, rainwater harvesting and re-use within buildings is often not allowed.
Rainwater harvesting policies should address several issues, including:
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Intended use of captured rainwater: harvested rainwater used for irrigation will not need to
be as regulated as water that needs to be treated for consumption
Scale of project: residential and commercial projects may have different requirements, largerscale projects may need more guidelines than smaller ones
Process for permits: when permits are required, the municipality must stipulate the process
for and requirements of individual permits
Design and installation of system: including plumbing issues that may be associated with the
project
Water treatment requirements, if applicable
BENEFITS
The environmental benefits of rainwater harvesting are two-fold: water conservation and reduced
stormwater runoff. Additionally, there are economic and social benefits associated with rainwater
harvesting.
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Reduced potable water use (e.g. harvested rainwater use for irrigation and flushing toilets)
Reduced stormwater runoff as less water runs off impervious surfaces into surface water bodies
untreated, meaning fewer water quality, erosion, and habitat problems
Improved soil quality through minimization of erosion.
Reduction in utility demand
Decrease in stormwater runoff fees, if applicable
Promotes accountability in site management issues
COSTS
Estimated [Initial] Capital Investment: $25,000 + for commercial facilities; depending on the size of
the program, a consultant can provide for $10,000 – 50,000. Often building code officials can
research and propose their own amendments.
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http://www.southface.org/web/resources&services/publications/factsheets/27_rainwater-recovery-v2.pdf
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WWW.SUSTAINABLECITIESINSTITUTE.ORG ©2012 The National League of Cities, All Rights Reserved
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