We bought the house about 2 months ago and we are still learning about septic tank and all that. 2 days ago we noticed that after we flushed one of the toilets the tank was not geting any water( but there is some water in the bowl). My hubby checked something at the botom of the tank where the pipes are and he said that everything seems ok. Today we noticed the shower in the same bAthroom was not draining at all. All the other toilets and showers seem ok, so far. The only diference is that the pipes for the toilet and shower with the problem, go through an outside wall that was exposed to cold weather and very cold winds and they are the closest ones to the septic tank. Do we have a frozen pipe or a cloged sewer drain?