Hi. Hope you learned a lot from Scout. She really is a nice assistant but sometimes is a little full of herself.

All those Latin terms, sheesh!

Today we are going embark on a “poo” journey (not Pooh, although he does live in the woods too). There is a well known book called Everybody Poops by Taro Gomi. If you are going to live “off the grid” without any outside assistance, one of the big items that needs to be addressed is “poop”.

The topics of septic tank and associated drain field have been another pretty interesting intellectual journey. Somewhat unpleasant, true, but interesting nonetheless. The simplist sequence of events is water->toilet -> septic tank -> drain field -> air and ground.

First, water. One of the great wastes of our modern society is to flush the toilet with “potable” (water you can safely drink) water. This requires treatment and special handling of water that is going to be used in the toilet. Doesn’t make a lot of sense environmentally. In our cabin, we are going to use “gray” (or is it “grey”?) water for toilets and washing machines. Probably will use potable water in the faucets just in case someone is brushing their teeth.

Gray water is water that is not, strictly speaking, potable. Untreated rainwater, for example. Water out of the bathroom faucet. Laundry water. Per the building code in the county where the cabin is located, if you have any running water at all, you must have a septic system.

Black water is water that is from the toilet or kitchen sink (because of all the potential fat). Black water is unsanitary and goes right to the septic system. Swhoosh.

Next toilet. A modern convenience. Water saving toilets can use 1.6 gallons or even 1 gallon per flush. The technology is really pretty advanced.  Here is a diagram of the modern toilet. Search the web for “low flow toilet” for more info.

On to septic tank. Okay, now we have mixed the “solids” with our water and it has to flow downhill to the septic tank. There is a maximum slope the drain can have or the water outraces its contents. Not desireable. The effluent reaches the septic tank where it greets 1,000 gallons of its mates. The displaced water (about a gallon) overflows the tank and escapes into the drain field.

The septic tank is pretty big and made from concrete. It is waterproof. It is about 4.5 feet wide x 8.0 feet long x 6 feet tall. Our tank is buried 4 inches to 12 inches deep (it lies level with a sloping hill above it).

Remember, normally all water goes into the septic tank including gray water.  It is estimated that individuals use between 50 and 100 gallons a day. My question, “what happens if it takes 6 weeks to use 1,000 gallons?” Maybe I should just run rainwater into it until it fills? Your thoughts please.

Finally, air? and ground. In my ignorance, I thought that a good drain field substrate would be sand. You know, the water would just go right into the ground and then be filtered by the sand. Wrong. Actually, the clay in the soil benefits the drain field as it holds onto the water where the sun can evaporate it. Makes sense. Less likely for the bacteria to wash into the groundwater.

Tree roots like drain fields and they will penetrate the pipes and cause a lot of problems. Also, their shade (see above) hurts the efficiency of the drain field. I hear grass grows really well over the drain field. Erma Bombeck wrote a clever book about it – The Grass Is Always Greener Over The Septic Tank.

Now you know that the title should have been The Grass Is Always Greener Over the Drain Field but I guess her editor felt it didn’t have the same smell of success.

Now, the next time you use the “loo” you will have a greater appreciation of how much science really goes into that simple flushing sound.

Time for dinner…

Frank