Drain Brain - or - How I Thawed a Frozen Pipe

On Wednesday, my main drain froze. I could tell as soon as I turned on the dishwasher, the main bathroom’s toilet made an ominous chorkle and barfed up the contents of its connection, and the bathtub followed soon after. I immediately turned off the toilet supply and threw down some towels to catch the overflow. It was all clean water fortunately. Then I cursed. I cursed because this happened last year, and it cost me $900 or thereabouts to replace the mainline with a new one on a steeper grade with cleanouts. There is no way I want to do that again, and besides I thought I’d paid my dues to the draingod by surrendering a small fortune to his overlords.


Once I collected myself, I thought I might feel better if I knew exactly what was what. To view my drain, I have to open the skirting around the house, and then crawl like a commando into a 14 inch crawlspace, under steel I-beams and around suspended gas lines. The ground is gravel, hard on the knees, but at least it is dry. It’s dark and confining and because I have a vibrant imagination, it induces claustrophobia. I can only move on my belly, (I am a petite woman, so it’s a pretty small crawl space). All work has to be done from a prone position, so you better take everything you need with you and put it in an accessible pocket. It takes some girding of the loins to prepare yourself for such a mission, believe me.


I knew I had a dryer vent down there, very proximate to the elbow where the main downflow joins the 35 foot span of ABS. I had a notion of creating a kind of enclosure down there and venting the dryer into it, so the temperature would warm up from the ambient minus 30C to something closer to freezing.

Alas, the dryer vent was already circumvented by the overlords, and was unusable for my purposes. It did smash up right on the elbow though, so its heat wasn’t wasted.


I did a little tour along the length of the pipe, mostly backwards because it’s too narrow to turn around easily, and saw that the lay of the land was from the source of the freeze:


-elbow with cleanout on ground
-15 feet straight 3” ABS (frozen solid)
-flex join
-10 more feet
-viewing hole cut in top in which I could see ice
-four more feet of line, angling downward
-drain from back bathroom coming down to a wye
-exit to septic system underground


I mention this in case you are here looking for help, you will have an idea of the layout.


The freeze-up occurred because there was a constant flow of water from my filtration system, combined with severe winds and an overnight temperature of minus 30. As the water dribbled out along the almost uncanted pipe, it began to freeze because it didn’t have enough gravitational impetus to get to the steeper angle near the septic. It started backing up, and soon the whole 20 feet of pipe was frozen solid. I could tell it extended the whole length because I could see and feel ice at the viewing spot. Warning to those who would leave water running to keep the water lines clear!!! Make sure your drain line has enough of an angle to drain properly if the water starts to crystallize!!


When I got inside, I started researching the web. I found some very amusing sites that said things like “no way would a drain line freeze except in a trap maybe, so detach the trap”, and “it’s so cold here, it’s minus 15” (child’s play my friends), and “pour a tsp of household salt down the drain” (guffaw). I think these sites were from some lovely semi-tropical locations like Georgia, which sounds like a great place to be actually.


Well, let me tell you one and all, that drains can freeze for miles. And it’s not Unthawed, it’s THAWED, as in “I want this baby thawed ASAP”. If you Unthaw something, you return it to ice.


I solicited advice from friends and acquaintances. Men favoured “pumping a Herman Nelson under there and giv’n’er”. Women were sympathetic and wondered what a single gal could do in such a situation, or they were incredulous, “what, again?”  like I'm not supposed to be visited by the same plague two years in a row.
 I researched various heaters, but I am afraid of combustible gases so close to suspended gas lines and what is probably a flammable house. I thought it would be great if they made a kind of heat blanket shaped like a carpet runner that you could plug in and thaw things out (they do). Or an electric snake with a heated head that you could use to steam open the drain from the top (they make them, but they are propane powered which freaks me out especially if you’re dragging it around by yourself).


In the meantime I poured a kg of salt down the bathtub drain.


A friend suggested RV antifreeze, so I researched that and found lots of cool info – propylene glycol is not toxic like its cousin ethylene glycol, and is metabolised into citric acid, so it will make your pets sick but not kill them, an important consideration here on the farm; it is used as de-icer on planes, it will not melt ice, but instead prevents it from forming, although one of my friends said it opened a frozen shower drain in his trailer.


I found a site that sells something called a powerblanket, which is an industrial heated and insulated blanket that will thaw ground down to 18 inches overnight. Wow! I would love one of those, but they are too expensive for a one time user. They are used by cemeteries in the winter, among other things. They have a range of useful products.

When I called the local co-op building supply, they suggested heat tape with an insulating wrap. I confess at this point that I consulted my tarot cards (yes, up until now I sounded relatively sane) but sometimes a gal just needs a little guidance, and their advice was FIRE. So I opted for heat tape.


I spent two hours Friday afternoon wrapping a 24 foot length of heat tape around a span of about 15 feet, the first 4 feet I was forced to lay the tape along the side because it was resting on the ground without a gap underneath. The temperature was minus 15, just at the borderline, any colder and the tape will become too brittle and you must warm it up. Read the instructions on heat tape carefully. You must tape the thermostat to the pipe and insulate it as well if you choose to insulate the pipe. Finally I plugged it in and hoped for the best.


Saturday went by, no change. I was thinking I might have to resort to another solution. I called up my friend Scott who mulled it over with me, and we decided I should next try infrared bulbs with reflectors and foil tents. I spent a restless night, worrying about it all. Such things as “which end should you thaw first, because if you thaw the outflow but it doesn’t have enough slant to propel the water down, will it just sit there and refreeze”, and “will infrared thaw water faster than radiant heat”, etc. It would all make a great science project for someone. The prospect of crawling under there again, possibly for hours, made me anxious.

 I awoke Sunday to a blizzard. It started Saturday, and was still going strong. We’ve had about six inches of snow and severe winds that began from the West, veering around to the Southeast by Sunday. I was not looking forward to driving into town for infrared lights, nor crawling down below in a gale. The temperature was dropping again too, down to minus 19.


I took a look in the bathtub – still some standing water there. No change. So I started fretting and wondering, should I take the car out and go get a wet vac? It's a blizzard, so driving is dicey. Should I take the toilet apart, wet vac as much of the standing water in the drain as possible and then send down a hose attached to my household steamer? I did the dishes (in a roaster, using the back toilet as a drain), then cleaned up the kitchen, did some vacuuming, had a shower. I washed the dog bed by hand, and put it in the dryer. I ran the dryer for about an hour altogether, drying the dog bed as well as the towel I used. When I went to start bailing out the bathtub again (I turned the filtration system on so it was backing up into the tub) I noticed the water didn't seem as cold as usual. I bailed out the tub since it was filling up rather quickly. When I went back, lo and behold! The tub was empty. The toilet was empty. The ice was gone!! That's a pretty big chunk of ice (15 feet long) to have been melted. So being cautious I didn't believe it, and went under the trailer to check -- all's dry and OK down there. So between a kilo of salt and a 24' length of heat tape and a dryer running, the ice melted. I'm still in shock after having worried for so long about it all. It took about 36 hours for the whole thing to thaw.