I just replaced my electric water heater - 40 gal tank. The old one was ready to burst at the seam - looked pregnant..... I install my own drain valves on all my heaters - to make it easy to flush. (pipe size is 3/4") I purchase a brass 2" nipple with a ball valve and a short nipple on the front of the valve so I can hook up a garden hose so I can drain the water into the nearby drain (which is code). With well water you would want to flush twice a year. I just did a flush on mine yesterday and it was freaking gross......one tell tale sign of needing a flush is that your hot water stinks like sulfur. Also, you may want to look into replacing the anode (if your tank is still salvageable). My 2 pennies.