Will autmotive anti freeze hurt septic tank ?

I am looking for advise on anti freeze that is ok to use in a septic system . I original had just planned to use R/V antifreeze until the jug I had outside froze solid at minus 10 deg. It was rated as good till minus 70, sold at the ‘save big money store”. Actually 2 different brands .Reading the fine print it said burst protection to minus 70 . I need it to stay liquid not solid . I fear I may have a low spot in my drain pipe allowing water to sit in the pipe. I am going to be gone a few weeks and don’t want a frozen sewer when I get home . My thought was pour a quart of antifreeze down the drain to displace any standing water. Just concerned on the affect it will have on my septic tank . Is there a r/v antifreeze that will be safe as well as staying liquid ? All comments are appreciated. Thanks

If it were me I’d get a plumber out and have him put a camera down the line and figure out what is going on and where it is. You can also rent one for a couple hundred dollars a day at some rental centers. However real plumbers would have the experience and accessories to figure out exactly where the problem is. Then give you the best options for repair.

cheers wrote:

I original had just planned to use R/V antifreeze until the jug I had outside froze solid at minus 10 deg.

I sincerely doubt the ground temp here, is anywhere near that cold. Course I have no idea what the ground temp is where you might live.

cheers wrote:

My thought was pour a quart of antifreeze down the drain to displace any standing water.

A quart of any type of antifreeze is not enough to have any positive effect, unless your line is a very very short run.

munchy wrote:

If it were me I’d get a plumber out and have him put a camera down the line and figure out what is going on and where it is. You can also rent one for a couple hundred dollars a day at some rental centers. However real plumbers would have the experience and accessories to figure out exactly where the problem is. Then give you the best options for repair.

^^^^^^^ This is your best option. Fix the problem rather than put a Band-Aid on it.

Unfortunately repairing lines is not an option in winter nor is uncovering the tank .

Pour a couple gall9ns of moonshine down there. Antifreeze is not good for the bacteria in your septic but that amount shouldn’t hurt. Best to actually fix the problem and not worry about it.

cheers wrote:

Unfortunately repairing lines is not an option in winter nor is uncovering the tank .

Where are you located?
I can’t imagine the frost is much past 3 inches around these parts and at those depths I wouldn’t even think about freezing lines.

*EDIT*
Here’s the current frost depth from the weather service. Only 6 inches up in Duluth and 0 inches here in Rochester. 20 inches in Fargo however.

http://www.weather.gov/ncrfc/LMI_FrostDepthMap

Thanks I have re evaluated my plan and think that if I redirect the condensate from my furnace so it does not enter the sewer I should be ok . I suspect he issue before may have been an ice dam as a result of continual low volume of cold water entering the system when the house was left vacant for 2 weeks . The sewer pipe to the septic tank is above frost line and that cant be changed due to the nature of the ground being bed rock. Frost can easily surpass eight feet around here (Rainy lake). The pipe has survived for 30 years and only froze twice , the last time I now suspect was because of a new high efficiency furnace just installed. The first time I think was a frozen outlet in the tank causing a backup into the sewer allowing standing water.

When I see issues like that I cover the lines with bales of straw, the added insulation will keep the frost from going as deep. Also yes furnaces drain a lot of water, you need to make sure it has somewhere to go.

onestout wrote:

When I see issues like that I cover the lines with bales of straw, the added insulation will keep the frost from going as deep. Also yes furnaces drain a lot of water, you need to make sure it has somewhere to go.

Exactly what I was thinking. I’ve pulled square hay bales apart and layer it down a foot or so thick and then covered that with a plastic tarp before and my snowbird neighbors do the same thing before they head south for the winter. I think they actually use bags of leaves

Hay is bad thing to use . Deer love it and it has poor insulation compared to straw that has hollow stems . Down side to straw is it has seeds that attract mice and spring cleanup is messy . I use styrofoam panels over top of the tank and outlet, they are easy to deal with . The sewer line is the issue , it is not possible to cover it due to decking and topography

My Septic system at my cabin would freeze from every couple of years. Finally figured out it was the furnace condensate. We had a condensate pump installed and it has not frozen since. The pump has a reservoir that collects the water till it reaches a certain level then pumps it all at once into the sewer line. The dripping of the condensate line is what causes the ice dam to form..

Mwal

munchy wrote:

<div class=”d4p-bbt-quote-title”>cheers wrote:</div>
Unfortunately repairing lines is not an option in winter nor is uncovering the tank .

Where are you located?
I can’t imagine the frost is much past 3 inches around these parts and at those depths I wouldn’t even think about freezing lines.

*EDIT*
Here’s the current frost depth from the weather service. Only 6 inches up in Duluth and 0 inches here in Rochester. 20 inches in Fargo however.

http://www.weather.gov/ncrfc/LMI_FrostDepthMap

Take the weather service frost depth with a grain of salt. In the fields about 6 inches. Roads, streets, driveways and parking lots 18-24 inches. Lawns and protected areas 0-4 inches. 35 mins SW of Roch.

cheers wrote:

Frost can easily surpass eight feet around here (Rainy lake).

Are you serious ? I always heard 50″ was the max it would go in this state…. How deep do they dig graves up there ?

big_g wrote:

<div class=”d4p-bbt-quote-title”>cheers wrote:</div>
Frost can easily surpass eight feet around here (Rainy lake).

Are you serious ? I always heard 50″ was the max it would go in this state…. How deep do they dig graves up there ?

Totally serious. The far northern section can hit 100+”

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Here is an interesting map from the Mn DNR.

https://www.dnr.state.mn.us/climate/journal/1801_frost.html

It has the frost depth from around the state for Jan. 2018 and 2017. My guess is the biggest factor is snow depth.

Most of the people around here cover their septic lines and tanks with bags of leaves in the fall if they are concerned. You can probably not put enough automotive anti freeze in your system to impact it significantly. A foot of 4″ pvc sewer pipe holds about 2/3 of a gallon of liquid. And if you have a “modern” septic system it probably holds about 1200 gals of liquid. To get really serious freeze protection you would have to fill about half of your septic tank with anti-freeze.

At $10 a gal for anti-freeze it would be cheaper to pay the pumper to steam out your lines periodically.

I was only trying to fill a theoretical low spot in my line not the tank so a qt or two of pure antifreeze would become up to a gallon mixed and fill the valley in the pipe. To late for that now, will hope for the best. I think diverting the condensate will be the answer and probably I don’t have a low spot in the line . My guess is the problem I had was previously was caused by low volume cold condensate creating an ice dam in the pipe. Lots of insulation and snow on tank this year , no chance the tank could freeze!
Thanks

djshannon wrote:

Here is an interesting map from the Mn DNR.

https://www.dnr.state.mn.us/climate/journal/1801_frost.html

It has the frost depth from around the state for Jan. 2018 and 2017. My guess is the biggest factor is snow depth.

Most of the people around here cover their septic lines and tanks with bags of leaves in the fall if they are concerned. You can probably not put enough automotive anti freeze in your system to impact it significantly. A foot of 4″ pvc sewer pipe holds about 2/3 of a gallon of liquid. And if you have a “modern” septic system it probably holds about 1200 gals of liquid. To get really serious freeze protection you would have to fill about half of your septic tank with anti-freeze.

At $10 a gal for anti-freeze it would be cheaper to pay the pumper to steam out your lines periodically.

Snow depth is a major factor in frost depth. Along with low temps and the duration of low temps. Compacted soils is another factor, less air space = deeper frost levels.