Engineers really know their stuff

[warmstrong1955]

FYI, my water heater is in it's own little closet, accessible only from the outside of the house. If it leaks, or splits a seam, it will leak into the back yard.
Most damage done....dead grass from the hot water. Had it happen about 10 years ago. Grass grew back.....no big deal.
Our house was built in 1981.
My son's house, is the same way, and was built in the 60's.
Our house in Oregon, the water heater started leaking, but the heater was out in the garage, and the water ran out the big door. A little squeegee work, and a new heater...and away we went.

The tankless heaters are great, but I heard the same about hard water. In Alaska, we bought one, when the tank style heater flooded the laundry room. We had really good water there, so hard or iron water wasn't a factor in buying it.

[curtis cutter]

FYI, my water heater is in it's own little closet, accessible only from the outside of the house. If it leaks, or splits a seam, it will leak into the back yard.
Most damage done....dead grass from the hot water. Had it happen about 10 years ago. Grass grew back.....no big deal.
Our house was built in 1981.
My son's house, is the same way, and was built in the 60's.
Our house in Oregon, the water heater started leaking, but the heater was out in the garage, and the water ran out the big door. A little squeegee work, and a new heater...and away we went.

The tankless heaters are great, but I heard the same about hard water. In Alaska, we bought one, when the tank style heater flooded the laundry room. We had really good water there, so hard or iron water wasn't a factor in buying it.

I have a mechanical room in the basement for these items but I did not anticipate the failure to be a leak under pressure hitting the wall and running down. Fortunately not on the furnace or electrical panels. I have a catch pan under it but not around it. I have seen them slow leak but never spray. Fortunately carpet over concrete floors in the basement and a wet vac got it up. Just let the dehumidifiers run now. Had the tank replaced in two hours so at least we had hot water. Sized down to a 40 gallon from a 50 gallon since the kids have left the nest.

[warmstrong1955]

Whoa....
We had one that was a big time pressure leak, but the sheet metal cover made all the water go out the bottom. After I replaced the water heater, I took the old one apart, and it appeared the glass lining must have failed, and it rusted through at the vertical weld in the tank.

That was in our place in Alaska, where the thing was in the laundry room. Dead of winter. We had a glacier out the back door and across the porch and down the stairs....
Was glad it drained under the door though....would have flooded the kitchen and beyond if the back door threshold was sealed like it should have been.

[BadDog]

I was going to say the same thing. My experience has always been that leaks from the pressure vessel are always caught by the insulation and outer shell, then running out the bottom. It seems to me that there are only very small opportunities to spray, perhaps if the perforation occurred at the pop-off bung or something, otherwise only the piping is exposed, at least on the ones I've had the misfortune to have to replace.

But catch pans are just a part of the installation of a water heater as far as I'm concerned. I replaced the one in my rental house not long before we left. It flooded the utility/pantry room, but mostly ran out the door, and not really an issue with saltillo tiles (including kick mold). Still, it got mounted on a small (basically 2x4 pallet) platform to raise it up enough to get some drop to the outside wall about 5' away, and then through the wall. I was glad of that about a year back when the (5 year old) hot water heater let loose. That one failed pretty bad with a heavy flow that the 3/4" PVC was almost overwhelmed to discharge fast enough for them to find it and turn off the valve at the top. That would have made a mess for my tenants (and by extension, me) if I had not had the inclination to include that pan.

And yes, I suppose it would be nice if someone took the time and effort to put in a sloped shower drain "pan" with center drain and discharge to the sewer/septic. But what happens then if you don't notice the leak right away with the typical "small stream" issuing quietly from the bottom of the shroud? Filling up septic limits (perhaps if already taxed), wasted water with no idea why/where other than increases on bill, and thus delaying attention until it reaches truly catastrophic proportions, resulting in major damage and headaches anyway. I'll prefer to save the money on the secondary drain pan (and supporting) and prefer to run a drain pan to an obvious but non-damaging area.

My son on the other hand would probably install a wifi enabled sensor on the pan that both alerts his phone and triggers a valve to cut off the hot water, emails all members of the household alerting them to the temporary hot water situation, and schedules a plumber to address the issue. Actually, I'm only mildly exaggerating. He's got the whole "smart house" thing going to or beyond the modern limits of practicality (debatable IMO). Everything from his doorbell, door locks, garage doors (all on encrypted network), a half dozen Google Home pods arranged throughout the home (and on the pattio), his various TVs, thermostats, lights, all of it accessible from his phone to know if they are on/open/whatever. He walks up to his door, and it unlocks at his approach. Same thing on the garage doors, that also auto close behind him. He even worked with the garage door provider to fix some issues they had (like me, he's a programmer). And yes, he's got the security worked out (also one of his skills). I went over to one day after the locks were updated not thinking that I now no longer had a key to get in. He got a notification of movement at the door, could see me on the video camera, we actually had a short conversation as he unlocked the door and let me in. Other members of the household also walk in, and he can see exactly who arrived and when, when they left, all of it. Even can give out manual "one time" codes for cleaners (or plumbers), and so on. And that's actually not the half of it. Me, programmer or not, I'm more a big dumb parts kind of guy. KISS

[NP317]

Thinking of Steve G's comments on engineering stupidity.

I worked in Biomedical Electronics designing medical non-invasive test devices, defibrillators, pacemakers and related equipment.
Our Engineering goals were always safety, correct operation, reliability, and serviceability. And we ALWAYS battled the marketing department who wanted everything smaller and cheaper to build (and often the sales gang who made impossible promises to customers.) So many of our best designs were scrapped to satisfy those power-mongers. Our designs suffered especially in serviceability as a result.
Since I trained service technicians, I always heard The Stories of how it SHOULD be designed. And I agreed.

Due to my experiences, I tend to give Engineers credit for capabilities, along for sympathies for their frustrations.
And I STILL dislike marketing and sales people, in general.
There. I said it.
~RN

[John Hasler]

I worked for Sarns in the 70s and we got along quite well with sales and marketing. Of course, they had all been hired by Dick Sarns, who was a machinist...

The last startup I worked for was founded and run by a marketing man. That was a mistake.

[SteveM]

The last startup I worked for was founded and run by a marketing man. That was a mistake.

In the dark days for General Motors, it was run by an accountant.

Steve

[John Hasler]

Well, at least he could count.

[SteveHGraham]

And yes, I suppose it would be nice if someone took the time and effort to put in a sloped shower drain "pan" with center drain and discharge to the sewer/septic. But what happens then if you don't notice the leak right away with the typical "small stream" issuing quietly from the bottom of the shroud?

This is what the auto shutoff is for.

If a tank with a shutoff valve ruptures and you have it plumbed to drain into the septic tank (or outdoors), the maximum load on the drain is whatever is in the tank when it ruptures plus however much water leaks before the shutoff is triggered.

A small continuous stream isn't going to bother a septic tank. Everyone here has seen a toilet that ran for days before being detected. It won't blow the tank apart. If you live in the house and use the water heater, you aren't going to let it run forever, because you're going to go to work on the problem as soon as you realize you don't have hot water. Unless you bathe once a month, that will happen fast.

Damage to a septic tank is a hell of a lot better than replacing walls and paying for mold remediation. Believe me, I know.

[NP317]

Most water heaters fail with a slow bottom leak. Not a catastrophic puke.
The leak flow is less than using the water from the tank, so an emergency shut off valve (high flow detector) won't work.
It can't tell the difference between a slow tank leak and normal water use.
Oh What to Do?

Well, try maintenance.
Drain the mud out of the tank bottom annually. Plan on replacing the tank about the time the warranty expires.
Which reminds me: I need to replace our HW tank before it pukes!
Of course it is installed in a place that is impossible to protect with a drain...
~RN

[BadDog]

I didn't say damage the septic, but rather exceed it's limits if taxed. And that's exactly what happened with the house I'm in now. The septic system (a pit style common here) appeared to be at the end of its service life. Basically, full to the top because it could no longer dissipate the fluids. A new pit/system was priced around $8k, and I took that off my short-sale low-ball offer. But turned out, the previous owners had some issues that were never dealt with and over taxed it in a similar way. Resolving those I never actually had to rebuild it at all, and a check about a year after purchase showed it working well. So in my experience, yes, you can absolutely exceed the limits of a septic system due to a steady small stream of water over time as that's basically what the previous owners did. And I'm talking weeks or months, not days.

As for shutting it off, that assumes that the sensor, circuit, and shut off valve all worked correctly. Probably after setting completely unused and untested for between 7 and 15 years. How many people would actually perform annual (or otherwise) tests and PM on that system? I've got a manual gate valve that froze up after less than 7 years on the irrigation system due to hard water deposits, very difficult to engage, and then twisted off the stem trying to disengage.

But anyway, that was my point. And the point of my son's fascination with home automation. The more parts in a system, particularly "moving" parts, the more likely and more common a failure to perform will be experienced. If your water heater is below grade, something like a "frog" alarm and sensor/switch/sump may be your only practical options. But above grade, I'll take a pan and gravity drain to where leakage is obvious and non-damaging over a complex and more costly system every time...

[SteveHGraham]

And I'm talking weeks or months, not days.

Exactly my point. If your water heater fails and produces a slow stream big enough to bother a septic tank, you will know about it long before that happens.

As for shutting it off, that assumes that the sensor, circuit, and shut off valve all worked correctly. Probably after setting completely unused and untested for between 7 and 15 years.

I know you're not suggesting it's best not to try. We know things fail, but we still buy them and use them. I have a burglar alarm, smoke alarms, and all the associated sensors. Things like that fail all the time.

I didn't say damage the septic, but rather exceed it's limits if taxed.

resulting in major damage

Not sure what to do with that.

I'll prefer to save the money on the secondary drain pan (and supporting) and prefer to run a drain pan to an obvious but non-damaging area.

I would guess that it depends on the situation. I have a house that sits on damp ground, and when water gets under it, it's a big problem. I wouldn't want water pooling beside the foundation.

The leak flow is less than using the water from the tank, so an emergency shut off valve (high flow detector) won't work.

You don't have to detect high flow. I don't think that's even possible, since cutting the pipe with a Sawzall wouldn't make the water flow any faster than running two baths at once. You can look for water that leaks out. A cheap moisture detector under the water heater will work. They use them on boats. If you wanted to, you could do it with two bare wires. I don't know what technology they use in homes for stuff like this, but it has to exist, if I can invent it on the fly during an Internet discussion.

Drain the mud out of the tank bottom annually. Plan on replacing the tank about the time the warranty expires.

I didn't know it was possible to clean out a water heater. Now I'm wondering whether trying to clean an old one will cause a leak.

In any event, it's clearly better to prevent unnecessary water from entering the house than it is to do what the people who built my house did, which is nothing. I just paid a guy $3250 to do a very small mold job, and I don't have the estimate for the new drywall yet. I paid another company $15K, not including reconstruction. If the house I'm in now had a major leak, I think $75K would be a best-case scenario.