I have a 17 year old 40 gallon electric water heater. I don't use a dishwasher and almost all laundry is done using cold water. Within the last 3 days, showers become cold after 5-8 minutes. I have reset the high temperature shut off system button. Any suggestions?

All kinds of ideas here! First, tell me why you reset the high temp. limit button... was it popped out and had shut off by itself or did you just press it to see if that would help things?

Let me know, OK?

Mark