"Have you ever experienced a "water failure"? That is, have you ever turned on your faucet and found that no water came out of it? If you get your water from a municipal water system, the answer is probably "no."
Water pressure is very reliable. A big reason for that level of reliability is the water tower."
I have found it helpful to do the stretching exercises my physical therapist recommends. Do some core strengthening exercises, such as the ones highlighted at The Mayo Clinic. By keeping your core strong, your back won't put itself in a position to cause that sciatica pain you are having.