View Full Version : Is saltwater bad for Septic systems?

Original DMx
03/12/2015, 11:12 AM
I used to live in town and never worried about sending water down the toilet after doing a water change. Well, I moved to the country and recently set up a smaller system (60 total gallons) and did a couple of water changes without even thinking about it. Then I happened to read a small blurb on a different website stating that you shouldn't send salt water into a septic system. What are your thoughts and has anyone had any issues with their septic systems due to salt water?

03/12/2015, 12:23 PM
Concern for osmotic pressure comes to mind, but I can't say I have a personal tale to relate.

03/12/2015, 12:32 PM
I don't take a chance. I dump the salt water elsewhere.

Original DMx
03/12/2015, 12:48 PM
The concern from others was the fact that salt destroys concrete which is what the septic tank is made of. Others voiced their concern of it killing the aerobic bacteria of the septic tank, but nobody had any proof that it may indeed do so nor at what levels.

03/12/2015, 03:17 PM

I've been doing 20 gal water changes on my system for the past five years, and I'm on well and septic. I also have a water softener installed on my house system which discharges brine into my septic system. The softener was installed by my builder, who is a pretty big builder around these parts, hopefully they know what they're doing.

In an abundance of caution I have my septic tank pumped and inspected every year, and I've always made a point of asking the service tech to be particularly mindful of salt damage. He's never noticed any problems and the system is 12 years old. (Touch wood!)

Again, FWIW, and as always YMMV.

Original DMx
03/12/2015, 04:11 PM
Yogre, that's good to know. Thank you.

03/18/2015, 07:19 PM
I wouldn't put in a septic, although a lot of septic tanks are now plastic/fiberglass so in theory it wouldn't hurt that portion. If yours is concrete I definaltly wouldn't put a ton of salt in it.

03/18/2015, 07:42 PM
I really do not see the problem given a moderate reef system. I live in NJ and I have 2 tanks, a solids at 700gal and a liquid at 1000gal. From there it's out to a leach field the potential volume of a swimming pool. Given that both I and my wife shower daily as do both my children, run the dishwasher, do a load of laundry....oh and toilet flushing. Do you really think a 30-40 gallon water change per week would really do much when you dilute it out with daily water usage. I also doubt salt added to the septic tank would be of any significant level to damage the concrete. As far as damaging the bacteria in the leach field....probably not. Think about all the surfactant, possible chlorox, antibiotic laden waste from those sick in the house going to the bathroom . We dump enough road salt every winter to wreak havock on all the streams and waterways! Now that is a problem.

Original DMx
03/18/2015, 09:56 PM
Yeah, I was surprised at how much water a typical family goes through. We had our septic pumped out and then I checked the level two days later and our 500 gal tank was already full (who knows for how long). So I suppose "Pbetz" is correct about the dilution of the salt.

I'm just glad to hear nobody has had a problem with it, that eases my mind.

03/19/2015, 06:12 AM
i live alone in the farthest corner of the boonies and have a 1,000g septic tank. been out here 17 years and so far, have never had a problem **knock on wood**. i run tubing out my front door when i do water changes so the saltwater seeps through the cracks in the wood on the deck and kills all the weeds.

03/19/2015, 04:13 PM
I have an aerobic septic system. It pumps itself out almost daily depending on the amount of water use. My water softener puts saltwater in the tank. I havent seen any issues due to the softener. I am gonna be putting in a 720g this year and plant on putting the water changes down the drain line my builder put in my wall during the build. I think the water usage will dilute it and it will get pumped out via the sprinkers before it has a chance to harm anything (assuming it would at any concentration)

03/20/2015, 12:01 PM
just drink more water, your pee will be less salty thus negating the saltwater you pour down the drain.

03/20/2015, 02:54 PM
I have lived at my current house for 19 years, and have been discharging aquarium SW and softener brine down it for all but 4 of those years. Have the tank inspected annually, and have asked the chap to look for concrete erosion specifically - no damage!

03/20/2015, 05:14 PM
concrete only errodes by exposure to salt when the salt water is allowed to penetrate the conc. and then DRY. the crystals that form wedge the conc. apart akin to frost wedging. this is why sno melt kills your walks. :)

04/02/2015, 08:10 AM
I suspect the very small concentration of salt will cause less of a problem than the host of other chemicals we flush and drain. Also, remember your septic system is dynamic and has fresh water coming all the time and water flowing out all the time. I seriously doubt there is any salt build up.