Art Ludwig

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since Nov 04, 2013
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Recent posts by Art Ludwig


(thought I already posted on this one, too...hmm.)
(Don't you have a DVD out about Laundry to Lawn or something like that?)
Laundry to Landscape
Laundry to lawn= common error x2 (one having a lawn, two irrigating it with greywater)

--At what point does greywater become considered dark greywater? Similarly, at what point does dark greywater become blackwater? I'm curious both from a legal standpoint and from a more practical standpoint. For example, if I were to wash in the tub just after having defecated (but having wiped thoroughly), I would assume that is considered still greywater. Correct?
...if I am going to be washing lots of cloth diapers do I need to consider it blackwater?
Legally, yes. Practically, your home and everyone in it is already covered in a light sheen of baby fecal matter, so the significance of the added exposure from having the laundry water under mulch out in the orchard = nil.

Are there certain things (e.g. coliform, etc.) that we need to test the water? If so, what concentrations are considered the range for each category? Or perhaps, is it more of a non-precise continuum; you'll know it when you smell it?

I don't think anyone has really pinned this down quantitatively, either legally or practically. Having done thousands of fecal/ coliform bacteria tests, I think testing greywater for most people would be a waste of time and money, because there is a tremendous amount of noise, it raises almost as many questions as it answers and it takes a lot of data for an accurate mental model to emerge from the fog. (If you want to do this for drinking water, wild natural waters or blackwater though, see Water Quality Testing: How to Do Water Tests Simply, Inexpensively and Accurately

Speaking of accurate mental models, anyone interested in this topic must read this page we wrote on conversion factors between MPN/ 100ml and buttwipes per swimming hole, bathtub, etc.

--Does contamination of a greywater source last indefinitely if the source of blackwater is removed? For example, in the case of cleaning the dirty cloth diapers in my washing machine, do they permanently contaminate my washing machine or can I safely say that after x number of washing other non-blackwater rated material it would be safe to say it is a greywater source? Would I need to disinfect the washing machine?

The concentration of pathogens will dilute logarithmically with each clean washing. After say, two clean washes I reckon you'd be back to background noise of the fecal coliforms that are blowing through everywhere from dried dog feces and whatnot.
Only if you plan to convert the washer to a drinking water or beer making vessel would it make sense to disinfect it.

Thanks for all your help in understanding these questions (and all the other ones on the forum too)! I am pretty sure that I can safely say that we are all overjoyed to have you out here sharing your knowledge on this matter!

You're welcome--it's been a pleasure, and with that I'm signing off —

5 years ago
Hi, Rose...

I swear I answered this previously...perhaps it didn't go through.

I think all the previous answers are on the right track.


• I have successfully created basins a bit at a time over the course of years, to avoid massive root disturbance
• Trees chronically end up too deep. We have an awesome new mulch basin drawing (one of several in the new edition) that shows a variety of measures to combat this...comments welcome.


5 years ago

I agree with the others who have supported individual on site systems.
An acre is a ton of space for greywater for one house. If the perk is decent, branched drain systems should be great. If not, you could go with wetlands.

The diversion to sewer is primarily needed for compliance in uptight locations, secondarily for people who can't figure out not to buy toxins and add them to water inside their house, only thirdly if there is insufficient on site capacity.

Temps will be higher 1) under mulch, as you say, and 2) because greywater brings heat with it from the house (unlike septic effluenti

Yes I can help figure out the design...quite busy tho.

Good luck,

5 years ago
Sorry no ebook plans for Create an thinking of doing an ebook version of the builder's guide...though that wouldn't apply so directly to your situation.
5 years ago
I have always been a big believer in the purification powers of mulch, soil, and all the stuff growing in it...especially mycelium. If anything can treat pharmaceuticals, petroleum, etc...that's it.

I quickly became a skeptic of treatment before irrigation., at least for low volume systems. I think having the mycelium as part of the receiving landscape is a fabulous idea.
5 years ago
If water is scarce, suggest you skip the wetland
5 years ago
1. Is it necessary to provide some sort of remediation (constructed wetland, aerobic roots, etc) before the fig roots interact with the grey water?

2. Should I install an overflow for the system in case the basin fills to capacity?

3. Is the pond liner necessary in this system? I would prefer not to have it, and allow the fig roots to go deeper, but am concerned about saturating the soil around the building walls.

Don't know...depends primarily on your soil, secondarily on your climate...better to ask some local builder.

Also, see comments on gravel under
Error: Distribution of grey water through perforated pipe or other system where you can't tell where the water is going
better to use a opened bottom chamber such as an infiltrator or half pipe.


5 years ago
Well, so glad you asked! This happens to be *exactly* the sort of situation the Builder's Greywater Guide was written for.

Systematic change in regulation is a time consuming process.The Builder's Guide is designed to help save time on this. It is basically an infomercial targeted at regulators and policy makers, to help them understand greywater and be comfortable regulating it in a common sense way. (A number of people have weighed their time against the cost of the book and just bought one for their local building guy bought about 50 and had us send them to a whole bunch of regulators and policy makers).

The same model greywater codethat is in the book is also posted in our greywater policy center, along with a bunch more info.

You could also suggest he call Larry Fay, head of environmental health in SB County, who used to work in Washington.



5 years ago
Mmm...not much to go on here...missing info:

Distance to creek?
Slope aspect?
Perk rate?
Is all the available space under the structure?

but I'd say:

1) Use a Laundry to Landscape system to send the washer water to the uphill side of the house, up to the height of the washer, to get it further from the creek
2) Do whatever size swale + mulch thing you can manage for the rest of the water...ideally not under the structure
5 years ago

Error: storage of greywater

Note especially the photo of the greywater to blackwater conversion tank...
5 years ago