How to handle waste saltwater on a rural septic (sewage) system?

RobertP · Oct 17, 2017

Wife and I are in the planning stages to build a house that is on it's own well water and own sewage system. I would like to add a larger tank and a fish room so my water volume will go up and thus waste saltwater would go up. Let's say the 40-50 gallons of saltwater to go down the drain a week. You cannot just dump it out on the grass or you wont have grass much longer.

So how bad is saltwater to a sewage system? Been reading that large amounts of saltwater will kill the bacteria that is required to make a sewage system work properly. So how much is bad or can you just add additives monthly to the septic to keep the saltwater from killing all the "good" bacteria? For people on their own system what do you do?
Thanks.

RobertP · Oct 17, 2017

Hmm well found this article and perhaps it is not that bad after all.
https://inspectapedia.com/plumbing/Water_Softener_Salt_Problems.php

bigroost · Oct 17, 2017

Not sure of the regulations, but out in the country where I grew up if we needed water to drain without pooling. Like your situation to keep from killing the grass, we would take a 55 gallon drum drill a bunch of holes in it, fill it with rocks then bury it and run the drain line into it. I can't imagine the saltwater would be considered a pollutant but have no idea.

brandon429 · Oct 17, 2017

pending further article searching, ill call it nonharmful bc it goes into such dilution in the septic system. I think literally no special action is needed imo cant wait to see follow ups

pdxmonkeyboy · Oct 17, 2017

i would advise you to dig a little deeper. the issue being the concentration of salt. a water softener doesn't come close to the concentration of tank water.

salt water will kill lots of bacteria ( hence the gargle with saltwater for a sore throat advice).

I have no idea what your situation is but I would avoid the risk of crashing your septic fauna and perhaps make a small infiltration sump in your yard.

like dig a big hole, place a large bucket full of holes in it and then fill with rocks and sand.

andrewkw · Oct 17, 2017

First of all I don't think 50 gallons a week down the drain is too much. I am pretty new to wells / septic and don't really understand too much myself, but through my research it does not appear to be a problem. I found several people dumping that amount in their septics but I suppose size of the septic and what else you are putting down can play a factor. That being said I dump 10-15 gallons of saltwater a week on my grass and it does nothing at all. I can't even get one weed to die from it. Vinegar is another story. In the winter I salt my steps with the saltwater. The reason I do this is I don't have a utility sink in my house and it's just easier for me to dump the water outside like this. The reason I do water changes is to siphon detritus so it's just easier to toss this out the door then down the kitchen or bathroom sinks.

If you haven't bought the property yet I'd have the water tested first. There seems to be an even wider variance between well water than city. I got real lucky getting 50-55tds out of my well and DI lasts over 1 year. There are lots of people on wells that change their DI weekly though.

LJLKRL05 · Oct 17, 2017

I have dumped it in my front yard a few times. It has never killed my grass.

Jaylivi1212 · Oct 17, 2017

I use my saltwater to water my mother's flowers & grass.

Clownman727 · Oct 17, 2017

Use it in a place you don't want grass or weeds to grow. I have a mulched area that i don't want anything to grow. And nothing does that's for sure. Free weed killer!!

theMeat · Oct 18, 2017

Saltwater from tank will not damage septic. Some think, and some do not, that salt from saltwater softener will damage the leach field section of a septic. But salt water softeners release WAY more salt than an aquarium, even a huge one, would. When you flush saltwater softeners they put VERY salty water into septic. Like 5,000 -10,000 ppm salt water. Plus they release chlorine or chloride.

Salt water will damage or kill most plants that need light, unlike bacteria that live in leach field, by denying it of potassium.

RobertP · Oct 18, 2017

Thanks for the advice.

mfinn · Oct 18, 2017

I've been in my current house for 26 years and have always had a saltwater tank of atleast 100 gallons and dumped the saltwater down the drain ( septic tank ) with no harm done.

brandon429 · Oct 18, 2017

I bet it boosts them upon dilution in the pit, due to micronutrient delivery. But maybe there’s a tipping point too, am wondering how the atypical salts get delivered back out

I could not see it affecting a septic system in normal doses initially

Special_K · Oct 18, 2017

Do you make your own RO water? You can try collecting the waste saltwater in a drum and pump it down the drain slowly using a small powerhead when you are making RO water. The RO waste will dilute the saltwater, hopefully making it safer.

mfinn · Oct 18, 2017

Special_K said:
Do you make your own RO water? You can try collecting the waste saltwater in a drum and pump it down the drain slowly using a small powerhead when you are making RO water. The RO waste will dilute the saltwater, hopefully making it safer.

It's just fine as it is. No need to do anything but dump it down the drain.

jda · Oct 18, 2017

Are you talking pond or leech field? Bacteria lives in saltwater too and you will not have enough to worry about going through the tank. Ponds can get into trouble if there is no run-in and run-off with a stream or rainwater - we had one get to 1.09 in almost a decade before I had to pump it out and fill it back up. Leech field should be fine since it will slowly go down to who-knows-where and not sit and collect.

In any case, the septic system worked like a charm for a dozen years until we moved and I never did anything to it.

KIRBLIT · Oct 18, 2017

theMeat said:
Saltwater from tank will not damage septic. Some think, and some do not, that salt from saltwater softener will damage the leach field section of a septic. But salt water softeners release WAY more salt than an aquarium, even a huge one, would. When you flush saltwater softeners they put VERY salty water into septic. Like 5,000 -10,000 ppm salt water. Plus they release chlorine or chloride.

Salt water will damage or kill most plants that need light, unlike bacteria that live in leach field, by denying it of potassium.

Just for reference our aquariums are 35 ppt which is 3.5% aqueous salt where as the water softener numbers you mentioned (don't know if they are accurite) are ppm which would be 0.5-1% so our aquarium salt would be much higher in that case. Chloride is also salt and we add it to our aquariums constantly with any mag and Cal addition and many other ways.

I live on septic and I just dump outside on the field being overly cautious because it's not worth the risk to me. I dont want to mess up the leech field or run into any struvite issues clogging up the pipes.

Thomas B · Oct 18, 2017

+1 for a dry well. hole in the ground with rocks to pour the saltwater into.

theMeat · Oct 18, 2017

KIRBLIT said:
Just for reference our aquariums are 35 ppt which is 3.5% aqueous salt where as the water softener numbers you mentioned (don't know if they are accurite) are ppm which would be 0.5-1% so our aquarium salt would be much higher in that case. Chloride is also salt and we add it to our aquariums constantly with any mag and Cal addition and many other ways.

I live on septic and I just dump outside on the field being overly cautious because it's not worth the risk to me. I dont want to mess up the leech field or run into any struvite issues clogging up the pipes.

Good points. A typical water Softener, depending on usage, will put 30-100 lbs of salt into septic per month. You’d need a pretty big aquarium with a pretty busy maintenance schedule to equal that.