We fell in love with our hilly land, but before we bought it, we were advised to have a soil evaluation report a.k.a. perk test   done to see if we would be able to build an at-grade septic system instead of a mound system for our future (now not so future) house.

The Wisconsin At-Grade system has been approved since 1982 on sites where soils are too deep to require a mound, but too shallow to install a below grade soil absorption system.

At-grade systems are less expensive than a mound system because there is no need for costly C33 sand.  They do less construction damage than in-ground soil absorption systems because because there is less excavation required in the absorption area.

We felt lucky to be one of the few sites in our township that met the qualifications.

The county sanitarian told us that the only other option was an outdoor privy permit for an outdoor toilet.  He said that to legally spend the night in any building on our land we need a septic system or a permitted privy.  Legally this privy could not be an old fashioned outhouse or a modern composting toilet.  The official wisdom in our county is that human waste has to go into a septic system or a buried tank – both of which must be periodically pumped and hauled who knows where.    Collecting everyone’s “septage” into one spot to deal with it, when people with enough space could be composting it instead seems like overkill.

According to the Wisconsin Department of Commerce, a certified pumper (septage servicing operator) can dispose of septage from the tank at a municipal waste water treatment plant or through land application if allowed by local codes and done according to septage disposal regulations.  Many tanks need to be pumped every 2-3 years.

Several factors determine tank pumping frequency:

  • Number of people living in the home
  • Water usage
  • Garbage disposal or whirlpool tub

At present while camping out, we have been doing just fine with a Luggable Loo.  This system is remarkably easy to maintain and odor free.  I see from looking at homes on the Tiny House website   that many Tiny House home owners use a basic lugable loo for a toilet, and have no gripes.  If any of you have found you can live with luggable loo/or composting toilet and gray water system for general washing purposes, more power to you.  This is without a doubt a more ecological way to go, and I’d love to hear about it.

But we are going with the official system to keep our local inspectors happy.  (We are already going to be asking a lot of our inspectors with whole tree timbers, strawbale walls and sod roof.)

Then to keep ourselves happy, we will add a composting toilet in one of our two bathrooms in the house, which will mean very little use of this septic system we are now in the middle of installing.  We won’t have a garbage disposal or whirlpool.

Here’s what we have learned about the care and feeding of our septic system to keep it as green as possible.

There are two layers of solids that form in the septic tank: one that settles to the bottom and a scum layer that floats on top.  Only the liquid in between these two layers is pumped to the drainfield.

To minimize the amount of solids:

  • Don’t flush cigarettes, diapers, feminine hygiene products, paper toweling or facial tissue.  They can contribute to the scum or sludge layers
  • A garbage disposal can contribute considerably to the sludge build up
  • Don’t put grease or oils down the drain from cooking, or skin lotions.  They increase the scum layer.
  • Use liquid detergents instead of powdered detergents because powdered detergents have fillers that add to the sludge layer.
  • Use toilet tissue that breaks down rapidly.  Test by placing a tissue sample (preferably unused) in a jar of water.  Cover the jar and shake rapidly.  The tissue should fall apart easily when shaken.
  • Install a filter on the washing machine water discharge line to trap lint.
  • A biggie that we want to make sure gets done right now is to have an effluent filter installed on the outlet of the septic tank to help prevent solids from flowing into the drainfield.
  • Keep hazardous materials OUT, like herbicides, insecticides, paint thinners, solvents, excess medications and cleaning products including bleach and drain cleaners (automatic toilet cleaning dispensers are frowned on).
  • It’s not necessary to use additives like septic system starters.

In this way we will minimize the amount of our “septage” being hauled hither and yon while staying out of conflict with local requirements.

11 replies

  1. I remember the plumbing guy using a pair of sheet metal shears to cut away the effluent filter on the system at our old house saying, “This’ll take care of any problems with back-up.” Any concerns about disease transmission using human waste compost on plants you plan to eat? Do the temperatures get high enough in a composting toilet to kill worrysome pathogens?

    • Hey Holly!
      I’m reading the Humanure Handbook right now ( ), and he details all the pathogens in great detail and what composting system will and will not deal with them. I’m still learning on that, but generally plan to use the compost from the composting toilet for nonedible parts of the garden at this point until I know more. I’m sure I’ll be posting more about this as time goes on.
      Thanks for your comment! Really fun to hear from you in this format.

  2. I’ve read that article, the Humanure Handbook. Absolutely fascinating.

    One suggestion for compost from toilets is using it to raise a nutrient rich crop like alfalfa or comfrey that can then be put on compost heap, thereby increasing the nutrients in an indirect way.

  3. And have you read the recent book by Gene Logsdon, Holy Shit? He did some extensive research on the use and misuse of excretions. Interesting read.

    • Thanks for the book suggestion, Dennis. I haven’t read it, but just put it on hold at the library. I’m fifth in line, but I hope to read it soon. I like Gene Logsdon.
      And one needs all the help one can with going against conventional practices.

      • You jest, surely, your library has a copy of the book, with that title? Our bunch of pansies here in Stevens Point does not.

      • It’s not joke, Dennis. The South Central Library System has the book, and I’m number 5 on the waiting list to read it right now.
        Stevens Point is an interesting part of the state. I used to take my daughters to Suzuki camp at UW-SP every summer when they were young.
        Do you get to the MREA fair?

      • MREA? Some years I’m out there sitting at a booth for the Wild Ones or the Ice Age Trail. Other years it depends on how energetic I’m feeling – do I really want to drive all the way out there and put up with parking and with the crowds? Some years I just feel like staying at home unless, of course, they have a particularly interesting speaker.

      • Yeah, I missed it this year because of a family health crisis, but I’ve enjoyed the last few years at MREA. It is crowded, but that makes me happy to see so many people showing interest in the topic.
        I do notice that there are quite a few recurring workshops that I have now seen, but I’ll probably go next year for last minute ideas as we are building our house.

  4. We are on a septic system. It was pumped last year at this time, we will probably have it pumped again because it’s our 1st year and I’d like to know what a year did to the tank. I often wonder about the laws around us, something to do more digging on. I know when my neighbor got his tank pumped a month ago I watched as they pumped and then drove less than 100yards to the field across the road and pumped it all back out. Something about this makes me sick and I don’t undestand it. Something that needs more research and questions asked. Until then we do our part to minimize our septic needs and use. I liken living in the country to camping (easy for us boys). I also have limited the amount of toilet paper I use, before (on city sewer) it was too easy to waste much of it.

    Your composting toilet…I will have to look into that. That sounds awesome and right up my alley. Thanks for the thoughts Denise!

    • Thanks for sharing about your septic system.
      I first began to think seriously about the whole issue after our older daughter came back from her junior year abroad. She was part of the International Honors Program out of Boston U. About 30 students and 3 professors traveled the world studying environmental issues and social justice. They Traveled to England, India, New Zealand, the Phillipines and Mexico and stayed in homes of local people in each country.
      They did their final group presentation on how destructive our waste disposal systems can be.
      But it’s not easy to get off this particular grid, but I am convinced we have really gone off in the wrong direction with flush toilets. Like so many of our “solutions,” they make things easier for the short term only.

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