A water heater tank collects what the water carries into it. Most of the upkeep is simple, and most of it falls to the owner rather than the installer, because the installer leaves after the first day. Set a schedule you can keep, write it on the tank or in the folder, and treat each check as a line in the log.
Sediment in the Tank
Minerals settle to the bottom and form a layer that holds heat away from the water and makes the burner or element work harder. On a set schedule, shut off the power or gas, attach a hose to the drain valve at the bottom, open the valve, and let the water run until it comes out clear. Close the valve, then refill the tank before restoring power or gas. A tank that will not drain at all is worth a conversation with a plumber before you force the valve.
The Relief Valve
The temperature and pressure relief valve is a safety part, so test it on a schedule. Place a bucket under the discharge pipe, lift the test lever gently, and let it snap back. Water should run out briefly and then stop. If the valve does not reseat, drips steadily afterward, or the discharge pipe is blocked, have it looked at before you rely on it. The discharge pipe should end in a safe spot, never in a sealed cap.
The Anode Rod
The anode rod is a sacrificial metal rod screwed into the top of the tank. It draws corrosion away from the steel. When you have access, check it. A rod that is mostly gone is a planning signal: the tank is now relying on its lining, and the tank's age matters more. Replacing the rod needs clearance above the tank, so measure that space before the day you need it.
Temperature Setting
Set the thermostat where the water is hot enough for your use and not hotter than you need. Ask the installer what setting they left, and write it down. Changing the setting in small steps and noting each change makes it easy to see what the tank is doing when something drifts.
Keep the Log
Each sediment flush, relief valve test, and anode check goes on the same page, with a note of when you did it. Keep the install year on that page too. The install year is the planning starting point, and the service life figures for this system are in the tables on this site. A written log shows you where the tank stands before a leak or a cold shower makes the decision for you.