lye soap vs. septic : LUSENET : Countryside : One Thread

Well, I've gone and done it. Opened my big mouth. I was talking to some non-homesteaders about soap making. I know, stupid move. Anyway, once they got past the horror of doing such a thing we got into the ingredients. The recipe I have has lye in it (thanks Meli!). Anyway, the nay-sayers are telling hubby that the lye in the soap will destroy the bacteria in our septic system and we'll have to have it dumped all the time because it won't decompose itself. Now I find it hard to believe that all you soapmakers are on a city sewer system. I also find it hard to believe that you would make a soap that is going to hurt your septics. However, I was 'ordered' :) by the hubby to "get on that forum and find out!" So I'm asking - does anyone have trouble with lye soap killing the bacteria in your septic? Thanks! Stace

-- Stacey (, November 20, 2001


I have a septic system and am assuming that most soap that I buy is made with lye so if that's a problem--no one in a rural area would have a working septic system. But I'm no expert here.

-- Ann Markson (, November 20, 2001.

There is no free lye in homemade soap. Lye is one of the ingredients, but it undergoes a chemical reaction with the fats (called saponification) that changes it into soap.

-- Julia (, November 20, 2001.

Ha! I just knew it couldn't be a big deal but I didn't know why. That makes perfect sense! Thanks!!

-- Stacey (, November 20, 2001.

We use lye soap. Great for teenaged complections by the way...anyway....bleach and other strong cleaners are much much harder on the bacteria than any plain ole lye soap would be. Remember all of those antibacterial handsoaps and dish soaps. They have got to be bad on the good bacteria in the septic too. I flush a hand full of bakers yeast down there every once in a while. Don't remember who told me to do that, but it seems to work.

-- Nan (, November 20, 2001.

Tell hubby that ALL soap is made with lye. No lye, no soap.

Like Julia said, there will be no lye left in the finished soap (if made properly).

However, be careful when washing up your soapmaking equipment and utensils. There WILL be active lye on, I usually let my equipment sit overnight. The ingredients can then finish the saponification reaction. As for the container which contained the lye solution, I dump in a little vinegar to neutralize the lye. How much is guesswork, of course.

The yeast is a good suggestion.

-- Sharon/WI (, November 20, 2001.

there isnt any lye in the soap,, AFTER it turns to soap. Thats what makes it soap,, so , therefore,, there wont be any lye in your septic,, and therefor,,, it wont kill the bacteria

-- stan (, November 20, 2001.

My Grandmother always told me that instead of using good yeast in your septic, break up a few pieces of old bread now and then and flush it. She said that there is still enough active yeast in it to keep your septic healthy.

-- Joanie (, November 20, 2001.

Grampa used to drop all dead mice and other "cat-kills" directly into the septic tank. He didn't have to dig up the tank each time-there was a cement cover visible at ground level, so all he had to do was slide it over and drop it in. This kept the decomposing bacteria active.

-- Charleen in WNY (, November 20, 2001.

All soap is detergent but not all detergent is soap. A great deal of what we buy as bath soap is actually detergent. Brands like Ivory, Fels Naptha, Kirks, and so on are soap. Brands like Dial, Lifebuoy and so on are detergent.

Any of it is perfectly suitable for use with septic tanks. Homemade soap that has been made even halfway correctly will not have sufficient free lye left in it to adversely affect anything with as much volume as a septic tank. To get enough lye out of soap to have any noticeable affect on the tank at all would leave so much unreacted lye in the soap that it would fair eat the skin off your body when you bathed with it. Make your soap and don't worry about it.


-- Live Oak (, November 20, 2001.

One of our friends said to put a pound of raw meat(hamburger) down there every once in a while. I told him that was not good to be wasteful and at the same time all my kids said, USE THE LIVER THEN! Haven't done that, couldn't bring myself to put anything in there that large. I bet that old sourdough starter would work well though. Every once in a while I have way too much starter and have to get rid of it. It makes the dogs tipsy, so I have to put it where they can't get to it.

-- Nan (, November 20, 2001.

You gou got me thinking. Now when I make soap which is almost everyday except weekends I clean the soap pan down the sink. At that point I am not sure if it has any lye that hasn't down it stuff but I have never had a problem and been doing this for years. I do have a septic plus a logoon. Is that different. We are rural and most areas do not perk. But I have never had anything back up except a few odd times when all the teens think you need a roll of paper everytime ya sit down!!!

-- Debbie (, November 20, 2001.

You make soap every day ????? Wow!

-- Patty {NY State} (, November 20, 2001.

Lye is combined with oil, in a process called saponification and the end product is soap.. All lye should be worked out by the time it is cured. If there was still lye in your soap it would harm your skin. Diane

-- Diane Coffey (, November 22, 2001.

I always wipe out my pan, blender, and utensils with paper towels and throw them out so I don't put the raw soap down the drain. Mary

-- Mary Fraley (, November 24, 2001.

Moderation questions? read the FAQ