# Septic systems and water softeners

**URL:** <https://boards.straightdope.com/t/septic-systems-and-water-softeners/510713>\
**Category:** Factual Questions\
**Created:** [September 19, 2009, 3:42pm UTC](https://boards.straightdope.com/t/septic-systems-and-water-softeners/510713 "2009-09-19T15:42:25Z")\
**Posts on this page:** 3\
**Page:** 2

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**Author:** ![watchwolf49](https://avatars.discourse-cdn.com/v4/letter/w/e9c0ed/32.png) [@watchwolf49](https://boards.straightdope.com/u/watchwolf49)\
**Post date:** [August 2, 2014, 1:14pm UTC](https://boards.straightdope.com/t/septic-systems-and-water-softeners/510713/21 "2014-08-02T13:14:54Z")

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> [@Unclebob9](#):
>
> It is best and simple to plumb the discharge from the backwash to a location other than the septic tank (in most cases).  
> Some the things hard on septic systems are soaps, paints, chemicals, grease, oil.  
> A water softener will result in using less soaps to clean and do laundry.  
> Many people run the discharge from their washing machine to a separate sump with its own mini leach field to preserve their septic tank. (simple home project).  
> Septic tanks work best with human waste and “Single” ply toilet paper only.  
> excess water is bad for your septic system.  
> Septic tank and leach fields need to be vented for the bacteria to properly breed.  
> A great septic tank additive is equal parts of: baking soda, brown sugar and Yeast.  
> (the yeast feeds off the sugar and the baking soda creates oxygen).  
> Since Hard water will plug up your pipes and faucets, it will most likely plug up your leach field as well in time.

ninja’ed by a newbie … welcome to SDMB … good to have someone here who knows his shit.

I would stress the soap part, especially laundry soap. A surprisingly large number of people use to much and THAT is bad for the tank. Also the actual dirt washed out of the clothes doesn’t liquify (duh) and sits down in the sludge. So you want your washing machine on the “mini-sump” as above. It’s a weekend project if you’re not afraid of shovels.

I have 6 domiciles on a 1,000 gallon tank … I pump that sucker once a year whether it needs it or not … keeps the crap out of the leech field and gives an opportunity to clean the baffles. Never seen no damn filter, but this is an old system from the 1960’s.

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**Author:** ![cath8r](https://avatars.discourse-cdn.com/v4/letter/c/59ef9b/32.png) [@cath8r](https://boards.straightdope.com/u/cath8r)\
**Post date:** [September 20, 2015, 9:00pm UTC](https://boards.straightdope.com/t/septic-systems-and-water-softeners/510713/22 "2015-09-20T21:00:42Z")

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> [@Unclebob9](#):
>
> It is best and simple to plumb the discharge from the backwash to a location other than the septic tank (in most cases).  
> Some the things hard on septic systems are soaps, paints, chemicals, grease, oil.  
> A water softener will result in using less soaps to clean and do laundry.  
> Many people run the discharge from their washing machine to a separate sump with its own mini leach field to preserve their septic tank. (simple home project).  
> Septic tanks work best with human waste and “Single” ply toilet paper only.  
> excess water is bad for your septic system.  
> Septic tank and leach fields need to be vented for the bacteria to properly breed.  
> A great septic tank additive is equal parts of: baking soda, brown sugar and Yeast.  
> (the yeast feeds off the sugar and the baking soda creates oxygen).  
> Since Hard water will plug up your pipes and faucets, it will most likely plug up your leach field as well in time.

This is a dead thread but I’m going to post anyway…

First, excess water is bad for the leach field, but the septic tank is designed to be full of water all the time. You get it pumped to remove excess solids. Or at least you are supposed to anyway.

The “venting” for a septic system has nothing at all to do with bacteria. You need the vent because you can’t flush a toilet into a sealed system (plug your vent and prove it for yourself). Water entering the septic system displaces both air and water, hence you need a vent. The bacteria in a septic tank is predominantly anaerobic (it doesn’t need air to survive). If you question this, you can research aeration systems designed for septic tanks. Those are designed to use aerobic bacteria along with an aerator, which pumps air into the septic tank (like a fish tank pump). And the yeast/baking soda/sugar mixture is a complete joke. I won’t even elaborate on that one, but yeast does not eat crap and toilet paper. If you have to feed it with sugar, why put it in the septic tank at all? It’s not magically going to stop eating sugar and start eating crap and toilet paper.

As for the “hardness” of the water damaging the leach field, I doubt it. The minerals and other elements are heavier than the water itself and most of it will settle to the bottom of the tank. Actually most of it will collect on your shower head and in your faucet screens. Salt water is also heavier than “fresh” water, so in theory it should sit lower in the tank. Eventually most of the salt will settle out of the water and drop in the tank, except for whatever amount is really dissolved in the water. Even then, most of the water displaced in the septic system is “fresh” water. The real killer of your leach field is solid particles that get through to the field. Put a filter between the tank and the field, and get your tank pumped at least yearly. It’s worth the 2 or 3 hundred dollars in prevention.

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**Author:** ![Smeghead](https://avatars.discourse-cdn.com/v4/letter/s/f1d935/32.png) [@Smeghead](https://boards.straightdope.com/u/Smeghead)\
**Post date:** [September 21, 2015, 7:54pm UTC](https://boards.straightdope.com/t/septic-systems-and-water-softeners/510713/23 "2015-09-21T19:54:27Z")

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The house is now sold. The plumbing and septic systems are now firmly Someone Else’s Problems.

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