It’s a Mudroom…It’s a Greenhouse…It’s an Indoor Leach Field!! Part Two of Solving the Greywater Conundrum

August 11th, 2021

Dear Readers,

Yes. Leach field. Just when you thought this addition could not get any cooler with its greywater absorbing plants and front entry hobbit door~ we fully made it into an indoor leach field!  

Ha! If your heads are screaming “What?!?” That’s fine. Ours are too. But I think we’ve got this…

Let’s start with the mulch basin. Remember how we were thinking of using that as the preliminary filtration means for our kitchen and laundry effluent before pumping it back into the house to our indoor green wall?1 Well, just as we ditched the green wall…we are now ditching the mulch basin.2 

Scratching it. Throwing it away. Mulching up the mulch. And…making a new and improved plan to propose to the PA DEP! Whoop whoop! So. Much. Greywater. Fun. 

Here is what we are thinking of replacing the mulch basin with:

William’s “Typical, Contained Leach Field”

We intend to keep this leach field in the same spot the mulch basin would’ve been: below our home but still within its envelope so as to ensure temperature consistency year-round. The leach field will of course have to be sized appropriately and able to handle filtering about 30 gallons per day of kitchen and laundry greywater. 

The treated greywater is going to go to a temporary storage tank…and then toooo…can you guess? Go ahead. Guess.

If you said to our greywater absorbing plants, which will be growing in another leach field, which will be contained inside our mudroom/greenhouse, alllllllllll within the envelope of this nutsy house….then yay! Because that is it. From one leach field to the next. 

The planter boxes for our greywater absorbing plants will each be their own leach fields. And they will look something like this: 

William’s sketch of our plants in their own leach fields

Do ignore the red ink…I know it looks like blood. It’s not. It’s greywater. William just didn’t have a blue pen at the moment. I promise we are not going that crazy…planting leech plants in our leach field…that absorb blood…and produce fruit…

So. Yup. Back to the leach field…greywater…leach field. Please make note of the ‘a.’ It makes all the difference.

Our greywater absorbing plants will hopefully absorb most of the incoming (already filtered!) greywater, and then release that water in the form of evapotranspiration. Our robust ventilation system will suck up that vapor and kick it out of the house. Any water not absorbed by the plants will be sent to (maybe) the greywater holding pillow. We are not sure if the treated greywater from the plants can share the same greywater pillow as the Hydraloop. That would be mixing non-NSF certified greywater with certified NSF greywater. Stinkin’ segregation.

We would obviously prefer if code would let us mix them…less pillows containing liquids under the house is probably for the best. Less maintenance. Less money. Just…less. 

Here is how we are currently thinking (and hoping…) our kitchen and laundry effluent, multiple leach fields, greywater absorbing plants, and ventilation system would work together: 

William’s leach field diagram

William found the blue pen for this one. Fortunately. No need to confuse and freak people out more than we already are!

Because we will be pursuing an experimental permit, we will be testing our water consistently. Testing the water will not only make code feel better about our crazy house…it will make our plants and us feel better! If you read “Potential Plants to Plant. Part One of Solving the Greywater Conundrum,” then you may have noticed that some of those plants have very specific pH levels that they thrive at. Knowing the pH and quality of water that is leaving the first leach field will help us determine if soil additives are necessary in the second leach field (i.e. more or less acidic soils), or if other measures need to be taken to enhance or maintain the health and happiness of our plants (change up what kind of soaps and shampoos we use…). Overall, happy plants mean less greywater. Less greywater means a happy us. 

Testing the water that leaves the second leach field is a matter of protecting the outside garden we intend to irrigate with said water…as well as a matter of curiosity. Do two leach fields, one even containing plants, make our water suitable to NSF standards? Could this be a prototype for future endeavors in future homes? Can we make this officially legal and acceptable in Pennsylvania?? 

So. Much. Excitement. 

So. Many. Indoor leach fields….

Thanks for leaching through!


1. If you need a refresher on how our previously intended system worked with our previously intended mulch basin and indoor green wall, you can read this blog, here.

2. And, if you need a refresher on why we are having issues with the mulch basin and are ditching the green wall, you can read our too-much-mulch-basin-filtered-greywater blog, and the brainstorm for the too-much-mulch-basin-filtered-greywater conundrum blog. Getting to this point has obviously been quite the process…and we aren’t done yet!


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© 2020 Sustaining Tree