During the recent 10-day stretch of below zero weather people have been learning.

Liz Stone is the manager for Thelen Septic Service.

“The biggest mistake people make is once they flush it down they forget about it,” she said. “They don’t ever think about it again. With a septic system, you have to keep that in the back of your mind, making sure your septic system is happy and healthy.”

Many people who have called for service since the below-zero stretch think their septic tank is frozen, but Stone said that seldom happens.

“A lot of calls that I’ve gotten folks think their tank needs to be pumped because it’s full and that’s what’s backing into their house,” she said. “But after I chat with them a little bit we determine that their tank isn’t full, their sewer line is frozen, that’s the problem. It’s such an unfortunate surprise.”

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Emergency calls to get lines streamed have increased dramatically. “We were averaging 20 calls a week just with thawing sewer lines,” Stone said. “It wasn’t anticipated this year because of the mild temperatures we’d been having.”

Lack of snow a contributing factor

“Unfortunately, with the lack of snow cover this winter and the immediate, severe drop in temperatures, we were pretty sure it was going to end up being busy from that point,” Stone said. “We’ve been getting a lot of calls from people who have never had problems before.

“In other years we’ve had fairly decent insulation from the snow, or people have been vigilant enough to cover their systems and lines with leaves to insulate them just in case we don’t get enough snow cover. This year out here, we’ve only got five or six inches of snow cover.”

Stone said what many people don’t realize is that snow only works as insulation if it is fluffy and undisturbed.

“People feed the deer or let dogs out in their septic tank and field area,” she said. “Those animals trample the snow and that reduces the ability of the snow to provide insulation over the system and lines. That can also drive the frost into the ground further and increase the likelihood that a line is going to freeze.”

Symptoms of septic issues

“You may hear a gurgling sound in your toilet when you flush it that you wouldn’t normally hear,” Stone said. “Another real key symptom is you will have backing up in a floor drain. If you have a basement, that’s usually where it starts. It may progress and back up in the showers, back up in the sink. It’s got to go somewhere. If it can’t go forward it will go backwards.”

She said many people refer to “having their tank steamed,” but that’s not what actually happens.

“We don’t steam the tank, we steam the line,” she said. “The tank will still have contents in it to keep it warm. Typically what freezes up are the lines. Only rarely do we see a tank that has frozen solid.”

Preventing freeze-ups

There are some things residents with septics can do to prevent freeze-ups.

The first is to check to make sure there are no leaking faucets or running toilets.

“You also need to keep water moving through the system,” she said. “Flush the toilet, run water, do laundry. Don’t have the water dripping, but have a stream running long enough to keep things open.”

Households with one or two people who normally don’t use much water need to increase their flow. “They may have to set a timer and go around every hour, run all the faucets, run the shower and flush the toilets,” she said. “Then make your way back through the house and shut the faucets off, then flush the toilets one more time. It helps keep the line open,” she said.

Having warm or hot water flowing into the tank also benefits the septic drainfield. “If you’re not using your system very much, your tank isn’t going to fill up to the point where it flows into the drainfield,” she said. “Then the line from the tank out to the drainfield can freeze.”

Maintaining flow the rest of the winter

Stone said once a septic service has opened the water lines going into the septic that doesn’t mean home owners are set for the rest of the winter.

“If you don’t keep using the system it will freeze back up again,” she said. “You have to stay vigilant.”

Another mistake people make is to associate warm air temperatures with being in the clear.

“They think they don’t have to worry about their septic system any more because the weather warms up,” she said. “The unfortunate thing is that now the frost is pretty deep in the ground. And even though it’s going to warm up, the ground isn’t going to warm up until spring, until it thaws out. So until then, you’ve got to be paying attention, listening for that gurgling and keep using the system as much as you can. You may have to set a timer in the middle of the night to get up to run everything during the night so you don’t wake up to surprises.”

One customer fills a bathtub with hot water morning and night, then pulls the plug to let it all drain.

“There are no guarantees,” Stone said. “That’s the frustrating part. But there are a lot of measures people can take to try and prevent it from happening.”

Pumping septic tanks is not recommended until later this spring. “Sometimes it can’t be avoided if there’s an emergency, but it’s not ideal to pump your tank during the winter months,” she said. “You should pump a tank every two to three years and try to do it from spring to early to mid-fall. You don’t want to get too close to freezing weather because it’s not good for your system.”