I know that it is illegal to catch and use graywater in many US states. What states and/or nations have favorable laws for graywater usage?

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    It's a bit of a broad and general question, and probably unanswerable in its current form, but I've provided one example of a regulatory regime where it is favourable, with links to all the regulatory detail
    – 410 gone
    Commented Feb 10, 2013 at 11:01
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    It is broad, and not amenable to one correct answer. Even so - those of us fighting to change legislation in unfavorable areas could really benefit from having this info to point to.
    – Laizer
    Commented Feb 11, 2013 at 13:08
  • Yes, I guessed that you were looking for some exemplary legislation to use as part of a campaign for change. And I guess you may be interested in countries where a lot of buildings have greywater recycling - I don't know where to find statistics, but that might make a good question in its own right: you could look at where the highest greywayer recycling rates are, and then look at the regulatory regime there.
    – 410 gone
    Commented Feb 11, 2013 at 13:17
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    A fine idea! I'll ask...
    – Laizer
    Commented Feb 11, 2013 at 15:19

2 Answers 2


The Building Regulations for England, and the national (largely voluntary) Code for Sustainable Homes, cover water efficiency and greywater recycling. The calculation for legal compliance includes the ability to achieve compliance by increasing your energy efficiency through greywater recycling, so it is actively encouraged by the regulatory regime.

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The specific legal documents are the Water Supply (Water Fittings) Regulations 1999 and the Building Regulations (parts G & H). The former requires:

backflow protection of any public mains supply “back up” connection. They also place an obligation on installers not to allow cross-connection of mains-fed pipework with pipes carrying recycled water, and to clearly mark the pipes to distinguish recycled water from mains derived water


Washington State recently implemented a new set of rules allowing greywater. Details: http://www.doh.wa.gov/CommunityandEnvironment/WastewaterManagement/GreywaterReuse.aspx

In my experience, greywater legislation is typically focused on plumbing and building codes, e.g. "Can I plumb my shower to drain in to the garden?" and not behavior, e.g. "can I take a shower in the garden".

A lot of behaviors are not so much legal or illegal, as outside of the purview of law.

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