Ours is in the basement.

Thousands of people in my area (mid-south) have them in the attic. Our new house under construction has it in the attic as well. It is rare that they fail, but they do....just like high pressure water lines on toilets can/do fail. Definitely a disaster if they fail in the attic, but it is the norm around here.

To be a bit safer, we bought a Marathon HWH, 105 gallon and a lifetime guarantee to not leak. We will see. Here is a picture of it in our attic.

I've had a 7 year old one blow - what a mess. It was on a slab and I lost the carpets - I hate to a imagine what an attic placement one would do. The tray is a joke.

In my area, the attic is not used very often. Usually by spec house builders when it is cheaper to put in the attic. My neighbor has a basement with a hot water heater in the attic! He bought it as a spec house. Takes forever for his first floor master to get hot water.

The answer of where to place a hot water heater has something to do with your floor plan, your intended fuel, and your foundation type.

Conventional tank hot water heater is a bit of a dinosaur and anyone building with any long term outlook should be planning for something different. There are a lot of options so there is usually something for everyone - heat pump, solar, tankless.

Most custom builds around here with NG do tankless hanging outside the house. We have solar with a recirc loop and tank in the basement. If you don't have NG, a heat pump pays off within 3 years but it is noisy so you should plan for that.

Just because it is common (in some areas) to put a hot water tank in the attic does NOT make it a smart thing to do!

Yes, attic placement makes it easier and cheaper to run vent pipes and, oftentimes, the water lines leading to various faucets can be a bit shorter if the tank is in the attic. But, IMHO the potential problems far outweigh any benefits.

Water heater tanks need periodic maintenance including testing the temperature/pressure relief valve at least once a year to ensure that it is working properly; and draining the water from the bottom valve to remove built-up sediment once or twice a year because sediment that builds up in the bottom of the tank reduces its efficiency and can cause premature tank failure. (The harder your water is, the more often the tank needs to be drained.) You also need to check the heater over periodically for evidence of small leaks - especially where hoses connect, and/or any signs of corrosion.

With a water heater in the attic however, it is often a case of "out of sight - out of mind." The homeowner never gives the hot water tank a second thought - until it fails! Far too often, hot water tank failure is accompanied by a deluge of water that overflows those dinky little drain pans and causes significant water damage to the ceiling of the rooms below before the homeowner even guesses that there might be a problem. I personally think the drain pans are worse than useless because, IF you didn't have them, you'd get a noticeable ceiling stain as soon as you had the first small leak...and that would warn you to replace the tank before it got any worse! With drain pans in place tho, sometimes the first problem that a homeowner notices is when the tank gets so rusted out that that the bottom of the tank literally falls out...sending 50 or 80 gallons of sludge and hot water all over the attic.

And even if you replace your tank long before you have a leak, replacing one that is in the attic can be a major PITA. Even if you have pull-down stairs for attic access, they often cannot bear the weight of an old water heater that is half full of water and sludge that cannot be drained because the drain valve is plugged from not having been drained for 5 years. Water weighs 8 lbs per gallon. The "sludge" that collects at the bottoms of hot water tanks weighs even more. So if an old tank has 25 or 30 gallons of sludge in it that can't be drained, it could easily weigh 350 lbs or more! You would wind up needing to rig up a block and tackle to lower the old heater to get it out of the attic.

Worse, it is not unheard of for a builder to install a large water heater thru the rough opening for the attic stairs and then, once the attic opening is finished out, the remaining opening winds up being smaller than the diameter of the tank making it impossible to get the old tank out.

Tell your draftsman to find another place for the tank. And then make sure your builder actually follows the plan because some are so used to putting the tank in the attic that they'll do that in spite of a plan that shows the tank located elsewhere.

Our tankless is outside

If you put it in the attic be sure you have adequate insurance for water damage. I'm in the middle of replacing all of the interior of a house that had a broken pipe in a third floor/attic bathroom. The contract price is $280,000.

ok, thanks everyone. I really don't want it in the attic.

I forgot to mention, they also have water cut-offs/flood stoppers if there is a drop in water pressure. This immediately cut off the water supply entirely. We will have that as well, just another piece of insurance if you elect to have your HWH in the attic.