Thank you for this site, excellent resource! I believe this question was also posted, but unaddressed under “composting toilet codes”

I am interested in building a net zero home in unincorporated L.A. County. Albeit costly and more complex than necessary, I anticipate being able to get a greywater system permitted and built. Permitting for a composting toilet appears to be a few years away as well.*

I am puzzled with how to address kitchen sink water since CA considers it to be blackwater. Unless code changes in that respect, I’m having trouble finding a viable solution. There is no sewage line nearby and the property size would require a prohibitively expensive alternative septic system. Any insight to a solution?

Thank you!




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You can ask for a variance to use kitchen sink water, or get it permitted under the Alternative Methods and Materials section of the code. Either of these options would require an open minded regulator. In LA County Health Department talk to Carlos Borja. (You could try the same strategy for a composting toilet. See IAPMO’s new Water Efficiency Standard for some guidance on permitting a composting toilet.)

An alternative idea would be to install a blackwater reuse system, like the Sludgehammer type system. Though you won’t technically be “reusing” the water, you can plant near the drip irrigation lines coming from the treated septic effluent and your plants will get the water anyways.

Good luck!

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