Our home is about 45 years old with a well and septic system. Last night, we noticed an odd noise from our downstairs toilet. After it was flushed, the water drained and the tank began to refill as normal, but at the end of the cycle, there was a strange sound like a rush of air or water through the system. After hearing this, we went through the house to check on other toilets. Every toilet made the same noise. We then turned on the faucets on both floors - the water basically ran as normal, but there were some sputtering/spitting noises intermittently while the water was running. We checked around for any obvious leaks and saw none. This morning we went through the same routine, flushing/running the various toilets and faucets with mixed results. Some areas seemed to have no problem, others still had the sputtering/spitting. Last night was the coldest of the year - and it is still quite cold today. I don't know if this has anything to do with the problem. Before we call a plumber, does anyone have any idea what might be causing this problem?