Draining hot water heater

I agree with some of it.What does the water heater changes with ?It depend.

I bought a plastic wand for cleaning out the deposits  from the bottom of a water heater - that stuff comes from two sources I believe - calcium and the  the anode rod's break down. every year I have cleaned out at least a 1/4 pound of the stuff with this wand - just attach to a hose ( it comes with a valve, and put it in the drain plug and wave it around to flush the water tank until no more carp comes out - prepare to get your feet wet! - works gerat and well worth the $8.00 it cost. On my old trailer the 6 gallon suburban, water heater's drain plug was also where the anode rod screwed in. I could stick my finger in the drain plug and feel the bottom of the tank- therefore I knew that the tank was completely drained when the anode rod was pulled out and allowed to completely drip dry. I guest I am going to have to check out this again on my new Atwood 10 gal tank.

The manual may be referring to the electric heating anode which is located inside.

The Atwood water heaters don't have an anode rod. They use an aluminized tank that isn't subject to galvanic corrosion. You should only see a plastic drain plug in the Atwood. Suburban water heaters use the anode rod.