Effect of Water Changes on Septic Tanks

[DoctaReef]

So I just bought a new house (I'm in Connecticut), and I'm starting a new system. My new house has a septic system with a water softener emptying directly into it and my home inspector, septic inspector and real estate agent all agreed that this was a huge issue. I learned that water softeners use sodium to remove water hardness and backwash the waste water on a set schedule. This water, containing dissolved sodium, will over time disintegrate the concrete of the septic tank, and cause it to fail. The consequence of this might cost $10K-20K to replace your septic system, and could also contaminate your groundwater. I've researched it: Discharging water from a water softener into your septic is actually specifically prohibited by the "CT Public Health Code Technical Standards for Subsurface Sewage Disposal Systems."
I don't know if the CT DPH knows about us reefers yet...

I'm pretty sure that a reef tank will, gallon for gallon, put more salt into a septic system than a water softener. I guess the solution is adding a dry well to my yard, which will allow me to discharge water changes there rather than the system itself. Has anyone else done this?
Has anyone had an experience where they've seen pre-mature disintegration of the concrete in their septic tank?

 

[Big G]

Had this discussion with the guys who pump my septic system last year. He thought is was not a good idea to be constantly dumping saltwater into my septic system. So I do dump the water into the ground away from both the septic tank and the leech/drain field lines.

 

[theMeat]

Think salt damage to concrete in septic is way overrated. Considering concrete bridge pillars in saltwater for a hundred years without issue.
With that said having a grey water well is a good idea, and will only prolong the life and function of your septic

 

[Hillbillyreefer]

I’ve never worried about it. There are lots of corrosive toxic gases created in septic tanks that are much more corrosive than a few pounds of salt.

My 50 year old cement tank crumbled a couple years ago. It had had salt discharge from a softener run through it for at least 20 yrs.

The cement tank was replaced with a fiberglass one, hopefully it will last almost as long as the cement one.

As for contamination of ground water, there is a long list of things I’d worry about contaminating the water before salt. Things like turds, and toxic cleaning chemicals.

 

[Drennon]

There is a reason that bridge decks in cold climates where salt is spread deteriorate far more quickly than bridge decks in warm climates.

Salt water corodes the steel in concrete. Oxydized steel then expands causing spalling (lumps falling out) or delamination (horizontal fractures) in the concrete that will cause it to deteriorate.

Whilst i cant speak for a septic system, I do make a point to siphon my water into the yard far enough away that it won't be close to my house slab.

My .02, I wouldn't put it in there

 

[theMeat]

Most household cleaners turn into fertilizer, but too much can disrupt the balance needed in septic for breakdown of solids.
Salt will not turn into fertilizer and if most types of plant life absorbs it they will become unable to absorb potassium and die.

 

[DoctaReef]

I’ve never worried about it. There are lots of corrosive toxic gases created in septic tanks that are much more corrosive than a few pounds of salt.

My 50 year old cement tank crumbled a couple years ago. It had had salt discharge from a softener run through it for at least 20 yrs.

The cement tank was replaced with a fiberglass one, hopefully it will last almost as long as the cement one.

As for contamination of ground water, there is a long list of things I’d worry about contaminating the water before salt. Things like turds, and toxic cleaning chemicals.

I agree, I'm less worried about salt contaminating my groundwater (my well) than the goodies that come from a leaky septic...

 

[DoctaReef]

There is a reason that bridge decks in cold climates where salt is spread deteriorate far more quickly than bridge decks in warm climates.

Salt water corodes the steel in concrete. Oxydized steel then expands causing spalling (lumps falling out) or delamination (horizontal fractures) in the concrete that will cause it to deteriorate.

Whilst i cant speak for a septic system, I do make a point to siphon my water into the yard far enough away that it won't be close to my house slab.

My .02, I wouldn't put it in there

I agree with you. I can show you the effects of salt on concrete with a picture of my cement walkway at my office. The snow removal guys put so much salt on it throughout the winter that its breaking apart in chunks. That being said, I'm not sure what exact salt they are using.

Here is a link to the CT Dept of Public health publication I found for everyone's benefit:
https://portal.ct.gov/-/media/Depar...HardwaterSoftenersFactsandIssuespdf.pdf?la=en

 

[DoctaReef]

Had this discussion with the guys who pump my septic system last year. He thought is was not a good idea to be constantly dumping saltwater into my septic system. So I do dump the water into the ground away from both the septic tank and the leech/drain field lines.

I'd love to do that, but I'd also like to use an APEX Dos to do automatic water changes to improve the stability of my system, and lugging buckets when its 10 degrees outside isn't my thing!

 

[Firemanreefkeeper]

I used to install water softener systems and we would always do the dry well to allow the backwash to drain out. We never put them into the septic because they were too far away. Our code is the well and system has to be X amount of feet away from the tank and drain field so they were never close enough. I can tell you from exp that brine water in a softener system is way more concentrated than aquarium saltwater. If the line was pulled for whatever reason the salt backwash would kill everything and nothing would grow there for months.

 

[theMeat]

Damage that salt makes to cement for snow ice removal is caused mostly by the thaw that salt manages, not by the salt itself.

 

[theMeat]

Yup, you’d have to do a whole lotta water changes to equal one softener backwash

 

[DoctaReef]

I used to install water softener systems and we would always do the dry well to allow the backwash to drain out. We never put them into the septic because they were too far away. Our code is the well and system has to be X amount of feet away from the tank and drain field so they were never close enough. I can tell you from exp that brine water in a softener system is way more concentrated than aquarium saltwater. If the line was pulled for whatever reason the salt backwash would kill everything and nothing would grow there for months.

Awesome...that actually makes me feel alot better.

 

[DoctaReef]

I used to install water softener systems and we would always do the dry well to allow the backwash to drain out. We never put them into the septic because they were too far away. Our code is the well and system has to be X amount of feet away from the tank and drain field so they were never close enough. I can tell you from exp that brine water in a softener system is way more concentrated than aquarium saltwater. If the line was pulled for whatever reason the salt backwash would kill everything and nothing would grow there for months.

Actually just did some research to back that up. Found some info that sodium in wastewater from a softener can be 6000 mg/L while seawater is about 10 mg/L. Does that sound right?

 

[Firemanreefkeeper]

Actually just did some research to back that up. Found some info that sodium in wastewater from a softener can be 6000 mg/L while seawater is about 10 mg/L. Does that sound right?

Sounds about right. The water in the salt container is saturated with as much sodium as the water will hold.
As for your concern about septic tank "goodies". My ex girls dad used to be a wastewater treatment operator and he said raw sewage can be filtered through 8 feet of sand and come out clean. I'd never test that theory but I'd say your well is over a hundred feet down so you should be safe on that front.

 

[Florida Sunshine]

I can tell you that saltwater will rust out a garbage disposal pretty darn fast. (Learned that the hard way.)

 

[DoctaReef]

Sounds about right. The water in the salt container is saturated with as much sodium as the water will hold.
As for your concern about septic tank "goodies". My ex girls dad used to be a wastewater treatment operator and he said raw sewage can be filtered through 8 feet of sand and come out clean. I'd never test that theory but I'd say your well is over a hundred feet down so you should be safe on that front.

Nice to hear that too. Hopefully it never gets to that point with regular pumping. Thanks for the info.