water heater question

How do you know when it’s time to change a water heater?

Here’s the extremely little I know about these devices, and I could be wrong. I’ve been told they have “sacrificial rods” inside that are designed to deteriorate and prevent the exterior from being eaten through, and that once the rods are gone, the shell will go and water will end up leaking onto your floor.

So, if that’s the case…

  1. Why aren’t the casings simply made out of a material that won’t break like that?

  2. How do I know when it’s time to change it? Ideally, it’d be swapped out the day before it springs a leak. Swap it too late, you’ve got water damage. Swap it too early, and you’re throwing a lot of money away. Is there any way to gague a realistic time to swap it out?

  3. Are tankless water heaters worth the extra expense? Do they last longer than the tank versions? I assume they get rid of the leak problem and save engery, is that accurate?

Thanks for any light you guys can shed on this subject…

Probably because it’s cheaper to make them out of steel, and a steel tank can easily last 20+ years.

You should check the anti-corrosion anode rod at least every couple of years. It typically screws into the top of the water heater tank. When it starts to look tired, replace it (the last time I did this, the new rod cost around $25 at a commercial pluming supply store.) You should also drain some water from the bottom of the tank, to remove crud that has collected there.

If you do this simple check, your tank can last a lot longer than one that’s neglected.

Congratulations for calling by it’s correct name rather than the common "hot water heater!

There are lots of variables here. First off, a tankless heater is probably the way to go
if you plan on keeping the house for 5, or more, years. Even if you don’t it may be a
good selling point. Properly installed, they beat hotwater heaters hands down.
Many local utilities have a hotwater heater replacement program, you might want to
see if this is available to you. Sacrificial rods (usually zinc) are more to protect your
plumbing system from electrolytic action between dissimilar metals, than the water
heater itself and should last 5 years or more. Many modern tanks are lined to inhibit
corrosion, but should be drained, or back flushed if possible, on an annual basis. I
believe the average life of a tank is about 15 years, but a bit of the maintenance
suggested can increase that. It also increases efficiency to insulate the outside of the
tank, there are kits available at plumbing and builders supply outlets, you just need to
know the dimensions of your heater. Keeping the tank thermostats (usually two) set at 120 degrees, or slightly below, will prevent accidental burns, save energy and help extend the life of the unit.

This can be a major operation if you have hard (high mineral content) water. Simple draining will be ineffective. The best out is to remove the lower heater cartridge and make a scoop, attached to one end of a length of broom handle, to enter the hole. Scoop out as much of the accumulated lime scale as possible, rinse and drain the tank, replace the heater, fill the tank and turn on the power. Check for leaks every day or so for a week.

Thanks for the advice. I think ours is approaching 15 years, and I have no record of previous maintenence – we’ve had the house 2 years, and haven’t done a thing to it. So I think it’s time to contact the local utilities and see if they’ll chip in for a tankless replacement.

How about gas heaters? There’s no means to remove anything from the side of the tank, as with an electric heater.

Ours is about 17 years old and as I’ve only owned it for about five months, I have no idea what, if any, maintenance has ever been done to it.

It gurgles and clunks now and then, and when I tried opening the drain valve, I got just a trickle of water, which would seem to indicate that either the valve is clogged, or there’s so much sediment that the drain opening is buried in muck.

Should I just plan to replace it sooner than later, and preferably on my schedule, as opposed to coming home one evening and finding water pouring out of the garage?

Should be no big deal to drain and inspect it. Remove the anode and check its condition. Possibly drop a light into the tank and see what the inside looks like.

IOW, a 15-year-old water heater might be on its last legs, but it might also be in fine shape and capable of a lot more service.

I have no experience of these, but again the best plan would be to clean & inspect it. You’d then have a pretty good idea about how much more service it could be expected to give.

Rather than waiting for it to fail, it’s obviously better to replace a heater that’s near the end of its life. But this should be based on condition, not age alone.