My wife has recently mentioned to me that the water heater for the sleeping quarters of the house has begun making some rather loud pinging/banging noises, and she convinced me to call a plumber to replace it. It needs to go- installed in '94, had a 5 year warranty, so is now18 years old. Considering my propensity for things in the house going downhill quick and costing more for reactive vs proactive repair/replacement, I'm going to have the work done this week. Using a reputable recommendation, I was quoted $900- this includes removal of old heater, installation and plumb of new Rheem 9 year gas heater (included in price), and flush/fail line to outside that is currently not there, from what I can tell. Is this a reasonable rate?