Answer: -I drain a bucket or two of water at least once a year to get rid of sediment .. water should run clear. I do not drain the entire tank. When the tank is heating I make sure it is drafting up the chimney. -You can try flushing the sediments out. (Note, I said "flush" not drain.) Simply attach a hose to that valve at the bottom of the tank and open the valve. The first burst of water will be very hot, but should cool off quickly as cold water enters the tank. Allow the water to run until it runs clear, then shut off the valve. Flushing is one of those things you should do routinely from when the heater is brand new for it to do any good. Once the minerals have built up the problem can't be flushed out (a jack hammer would be needed if that is the case). Also, flushing just doesn't work well on gas heaters, period. It's like trying to flush off the mineral buildup in the bottom of a tea kettle by just rinsing it with water. Any housewife (or househusband can tell you it just doesn't work. It does work (to an extent) for electric heaters because the mineral build is primarily on the elements which are self-cleaning. The scale flakes off the elements and settle to the bottom of the tank much like snow. If you flush them out regularly (once a month) they don't build up, but if you wait too long the "snow" can pack down into "ice" and it won't flush out either. There is a problem to watch out for with flushing, i.e. some of those scale flakes can get stuck in the flushing valve causing the valve to leak when you try to shut it off. Opening and shutting the valve a few times may or may not clear those flakes. Always have handy a hose cap to put on the end of the valve to stop any leakage that may occur. If you have *very* hard water (over 400 mg/L as CaCO3), you may want to consider putting a softener on the gas heater water supply line, since as I said earlier flushing is a so-so process on gas heaters.