We had several days of unusually cold weather. (At least for here) (lows in the single digits-high's around 20*) We have had no rain or moisture to speak of, and no snow cover. We woke up Friday morning with no hot water in the bathroom. After 30-40 mins of messing with the water, running hot water in other parts of the house, etc. the septic tank alarm goes off. Now I admit I know very little about our septic system. The previous owner told us the alarm goes off when the tank is half full. It was pumped shortly before we bought the house a year ago. I'm not even really sure where it is laid out in the yard, what of the little sticky up thingy's in the yard are septic and which are well, etc. Since money is real tight right now, til after Christmas we went on a water saving champain, and planned on getting system pumped in Jan. I used buckets to bail out the bathtub after showers, buckets to catch laundry water (wish we had a grey-water system, but we don't) and not flushing the toilet unless it REALLY needed it. The temps got into the 50's Saturday and about 4pm the tank alarm light went off. We resumed normal water usage and the alarm has not gone off again. Was something in the tank frozen? We didn't have anything back up into the house, just the tank alarm going off. I know that there are septic tanks in much colder climates than ours, so it seems odd that it would freeze, but I did read somewhere online that low moisture and no snow cover can cause a tank to freeze. Is there something we can do to prevent this in the future? We don't get super cold temps very often and we rarely get snow. Should I still plan on getting tank pumped out in Jan or should it last longer than a year? When we do get tank pumped I want them to give me a good lesson in septic systems.