Help! 2-story house with copper plumbing (20 years). Yesterday nothing unusual, this morning the water supply in the faucets/toilet etc. started dwindling till it disappeared. The same happened later on to the water from the faucets etc. in the upper floor. The main water inlet branches in two pipes, one to a water softener, the other to a single faucet: this faucet works ok, with plenty of water. All the faucets etc. from the water softener are dry. Using the bypass valve in the water softener did not help. Any idea of what could have caused such a sudden problem (and right during the Holidays) ? Thank you very much for any suggestion or pointer!