IT'S A FRIGID WINTER NIGHT, the family is preparing for bed, and someone yells from the basement, "There's sewage coming up this hole, and spreading all over the carpet!" A quick look outside shows a hose to the septic tank has frozen. Who wants to spend hours in the dark trying to thaw it? Having a well-designed and well-built septic system avoids many freeze-up problems, says Richard Zwicker, executive director of the Alberta Onsite Wastewater Management Association (AOWMA). The group formed in 1998 to deal with problems of septic systems. Phil Johnson, whose acreage is near Sherwood Park, Alberta, called in the experts after his sewer backed up twice. A camera in the sewer line revealed the 40-year-old septic system was crumbling. Johnson realized it was time for an upgrade, given his teenagers' daily showers. As well, the record amounts of rain had raised the water table, preventing the septic field from disposing of grey water. "Because of the age of this system, there was no point fooling around and trying to fix it," says Johnson. His pricey new Norweco system functions like a miniature sewage treatment plant. There's no sewage field or sewage mound. Clean effluent is piped into surrounding trees. Dale Ringuette, of All-Rite Trenching in Sherwood Park, who is installing Johnson's new septic system, says there is no single solution to septic problems. He studies the topography and soil in an area, the amount of land available, the existing system and finances before recommending repairs. Ringuette says poor installation is the main cause of septic tank freezing. It involves more than digging a hole and plunking in a septic tank, he emphasizes. A qualified installer knows about hydraulics, drain back, earth coverage and how water travels in cold weather. "I was at two jobs today - one insurance agent call, the other from another home owner-whose septic systems have been freezing for the past five years. They've finally asked someone other than their parents or their neighbours how to fix it, and so they're going to spend some serious money...to fix the thing properly instead of Band-Aiding it." With proper treatment, the freezing issues "will be reduced to almost nothing," he says. Since AOWMA was formed, more than 700 people have been trained to install, design and evaluate waste water systems. An estimated 20 to 25 percent of Canadian households have individual septic systems. It can be difficult to convince homeowners to invest in fixing or replacing them. Zwicker says people "spend lots on the hardwood and the granite, but because the waste water system is buried and hidden, they don't want to put money into it." Lifestyle changes have contributed to sewage problems. Previously, country dwellers used less water. They washed dishes in the sink, bathed twice weekly, and lacked built-in jet tubs. Increased water usage can send too much water into the septic mound, causing it to freeze during the winter. Zwicker has had more than one frantic call from an acreage owner whose septic mound has frozen. In one case, the caller's youngsters had used the mound for a snowmobile ramp, packing the snow and eliminating its value as insulation. Walking, skiing, snowmobiling or driving over the mound "can cause a septic system to freeze in a heartbeat," says Ringuette. Good insulation over the manhole cover and around exposed hoses is critical, says Zwicker, who suggests anything from straw bales to rigid foam insulation. It's also important to have well-fitting septic tank lids, and to ensure electrical plug-ins are in good repair, Ringuette says. He advocates alarms to warn homeowners if a sewer is backing up. - MARY MACARTHUR