septic line insulation question

[rv245]

Ok, here's the deal. This past winter my septic line froze. The line runs from about a 1 1/2 foot from the corner of the house to the septic tank which is about 20 ft from the house. The problem is this....... we have walkway (just dirt now) from our driveway around the garage to the side entrance to the house. Naturally during the winter we had to shovel including where to septic line is to get to the house. So there was really no snow helping to insulate the line. This is where it froze. Another problem if you can call it that is that our septic tanks are not buried real deep, as a matter of fact the openings on top are visible. This did help as I had a company come and un-thaw the line though the septic tank. So this summer I want to make it so that this doesn't happen again. I was thinking of putting some kind of insulation around the pipe or wrapping it with something. What would be the best thing to use or do to prevent this. I haven't measured how deep the line is down in the ground. But I'd say I'm luck if it's 2 feet. Another question is, would making a sidewalk out of pavers help insulate it and keep it from freezing during the winter? I would want to do something that could easily be removed if needed. I should add that this is in the northern part of lower Michigan.

 

[KANSASBOY]

Ok I be the 1st I'm also on a septic system .If I read this right it freezing in the line coming into the tank no water should be in this line . need to find way water is staying in line . If you look at this picture you see the water level
http://www.nesc.wvu.edu/subpages/septic_defined.cfm My inline & tank are only a few inches under ground to

 

[MScott]

My approach would be to dig down the line, level an area about 2 feet wide and place 2' x 8' x 2" sheets of Styrofoam on top of the line and then refill. I did this over the water line coming from my well to the house when underlying rock prevented me from digging deeper than a few inches. I have had no problems with freezing even though our frost line is 4 feet deep.
As Kansasboy mentioned, it is also important to find out why the water is staying in the line. There should be a constant drop from the house to the tank.

 

[sberry]

Here is what can happen,, not sure it did but using small amounts of water leads to freezing in the pipe. I hadf a shower drain freeze, there was a drip in the faucet and while there was no problem with regular use the drip caused ice to build in a cold pipe. The foam idea wont hurt.

My bud said he saw one earlier where the owner was looking in on a house, used to run a little water to make sure the plumbing was working,,,, water ran in to a cold pipe and froze off.

The insulation would be good, then make sure there are no drips and run some hot down the drain on occasion especially after a "flush" in the middle of the night which sends a small amount of cold in to a cold pipe.

 

[Bondo]

My approach would be to dig down the line, level an area about 2 feet wide and place 2' x 8' x 2" sheets of Styrofoam on top of the line and then refill. I did this over the water line coming from my well to the house when underlying rock prevented me from digging deeper than a few inches. I have had no problems with freezing even though our frost line is 4 feet deep.
As Kansasboy mentioned, it is also important to find out why the water is staying in the line. There should be a constant drop from the house to the tank.

Ayuh,.... Agreed, only I'd go with 4" of extruded polystyrene,...

 

[rv245]

Thanks so far for the help. As it was explained to me by the person who unthawed the pipe, the problem is with the HE furnace. I guess it builds up condensation and that goes into a line that eventually leads into the septic line. I kept the house at 55 during the winter as we came up to it every weekend and didn't want any frozen lines. We do turn off the pump, open faucets and drain tank down. I should mention that the crawlspace is very well insulated (looked in opening, but never been in it). So basically the condensation is going from a warm space and once it exits the foundation it's freezing down the line. I'm going to check that out also, but want to prevent it or anything else happening in the future. We was lucky as the guy just happened to be in the area when we called.

 

[Architorture]

sounds like your line is simply too high and based on the condition you are talking about I don't think any reasonable amount of insulation stacked on top is going to make a significant difference.

If I stack up 2'x2' insulation boards 2' high on my driveway with a cup of water in a small hole at the bottom after a prolonged cold period guess what...the water will be frozen.

Since the condensation from the furnace is the issue and the property is infrequently used when you put insulation over top of the pipe you are banking on heat from the ground to keep the pipe above freezing. Obviously the frost line is somewhere below the elevation of the pipe. You will need a very thick piece of insulation covering a significant area beyond the footprint of the pipe.

People like to think heat goes up, but it really just follows the path of least resistance. If you don't cover a big enough area any heat from below will simply go around you insulation.

 

[JerryB]

There is no reason to put a furnace condensate drain into the septic tank. The water should be relatively pure. Rerouting that slow water flow might be enough to fix the problem.

As others have advised, there should not be water standing in the line between the house and the septic tank. Sounds like there is not enough fall. Finding a way to fix that, along with diverting a slow cold flow from the furnace condensate drain should prevent ice buildup in the line.

I don't live where there is sub surface freezing, so can't really comment on the effectiveness of insulation, but I would think the temperature both inside and outside the insulation would equalize. That especially with an infrequent use situation.

 

[SALIV8]

I'd first close the vents to your crawls pace if they've been opened. Then I'd inspect inside the crawl space to be sure there are no drafts.

If nothing is found in that regard then I'd wrap the line with heat tape and insulation.

 

[HoosierMark]

So why not put an additional drain line on the furnace and drain it out to daylight in the winter? It is clean water so there would be no enviromental issues. This would eliminate the drain issue freezing from the furnace condensate. In the summer you could let it drain into the septic tank if you wanted to. A couple of pvc fittings, valve and a length of pipe and you are good to go.

 

[Reitwagen]

Dig it up put 4 inches of pink board above it 2 feet wide and you should be good. If you didn't shovel it off you would probably never have a problem. Your septic tanks are not going to be really deep. Chances are they are not engineered to hold the weight of 4 plus feet of dirt. I live in VT and we have had a few frozen water mains this year. The frost in parking lots went down almost 5 feet and less then 2 feet where it wasn't plowed.

 

[Hogger]

I had the same problem, as the condensate has a little bit of a trickle it will freeze. So what I did was place rock salt into the condensate drain line and the trickle now has a touch of salt in it and does not freeze.

 

[35mm]

I had the same problem, as the condensate has a little bit of a trickle it will freeze. So what I did was place rock salt into the condensate drain line and the trickle now has a touch of salt in it and does not freeze.

Now this is brilliant. So simple and effective.

 

[SALIV8]

Salt kills bacteria.

Bacteria = healthy septic system.

 

[dwm]

Normally a septic line won't freeze because it's large, short, sloped and the contents of the tank are generating heat. Part of my septic line was exposed all winter here in Michigan and did not freeze. Original builder put one of the joints about 1" inside the exterior of the block wall, which I'm surprised passed inspection. Joint was sheared off clean by frost heave before I bought the house (trickling septic into the block wall, which was a major issue). I repaired it, but didn't finish reburying it before the brutal winter hit and I had a lot of other repairs to complete (it was a foreclosure). I live alone in a 2700 sq. ft. home so my septic doesn't see heavy use for its size. But I do give it a gift every day.

I think your first line of defense for an HE furnace would be to eliminate the trickling: install a condensate pump that holds and dispenses 2 or more gallons of water per cycle. What does it have right now? Other options would include a tank heater and/or pipe heater. Note that areas with compacted soil will freeze deeper, so it doesn't help that you've got a trafffic area over the septic pipe. Pavers or poured concrete will likely aggravate the problem instead of helping. You want loose fill for insulation; mulch, grass that you let overgrow before winter, etc.

 

[jhelrey]

You might have a belly in the line causing the water to sit.

 

[luke_501]

ok, so i work at a septic manufacturer in illinois, and trust me... you aren't the only one who had frozen lines this year with the horrible winter we just had. Both inlet and outlets were frozen. We were receiving calls everyday about frozen lines. It's the nature of the beast when you live in an area where it gets freezing temperatures. Please do not put salt in your line as another poster suggested. That is a big no no. Like SALIV8 mentioned.. Bacteria = healthy septic system.

I have seen many different ways people have tried solving this problem and the only one i have seen that actually worked was burying the line deeper. Which means burying the septic deeper. And if the top of your septic is visible (unless it's aeration) it sounds like you don't have much fall, so burying your septic deeper isn't possible unless you go deeper than add a lift station. So in other words unless you want to spend a few thousand dollars to prevent freezing i would try to eliminate the trickling furnace and just keep an eye it.