Basement dam project

Our basement drain is about 4' up the wall. Which means that if our water heater failed we could keep alligators. 
 

The basement doesn't really slope toward a low spot so Im thinking of making a dam around the water heater with a sump pump in it. I have two areas I need some advice:

1. What to make dam with? Its an unfinished basement with concrete pad. Bricks and caulking? How high?

2. Looking for sump pump ideas. Most of them with a float want the water level up above the unit before it activates. I've never played with one before so I don't know how the float functions; could I rig a standard one to start at like 2" of water instead of over a foot?

I understand I could get a stand-alone float for the power but would prefer integrated unless the hive says otherwise

You need to dig a new sump pump pit into your basement floor with a floor drain in the lid and then pump the water up into your 4 foot high drain pipe. This is a poor example because the discharge runs under the slab and tees into a second sump which discharges out of the house.

Can you lift the water heater up and set it into a plastic tub? I have one under my attic hvac air handler which has a gravity drain down to the basement. 

At one point, I mistakenly bought a sump pump for another application in the basement (traditional sump). That pump would cycle on every few minutes or so to see if there was water there or not. It was noisy and used a lot of electricity and was the wrong pump for what I was trying to accomplish, but they do exist.

I worked for a guy who wanted to open a business that did emergency water heater replacement. At the time, he said that there were only a few different types of heaters in use, so it would be easy to control inventory, and that life expectancy was approximately ten years. 

In your situation, maybe it would be easiest to avoid failure and just replace the water heater proactively before it goes. 
 

That being said, my water heater is 23 years old, but it is in an unfinished basement. 

Any option of cutting into the basement slab, making a sump out of end capped PVC pipe, and putting the sump pump in that so you get the depth required for the float to activate the pump?

Is the heater gas or electric? 

Seems like if the water contained in the dam exceeds the height of a gas burner it will put the flame out.  If the gas doesn't shut itself down your basement will fill with gas.   (Is this possible?)

Electric would probably just trip the breaker.

Having said that I don't see any reason why bricks and chalk would not make a decent dam to locally contain water for a short time.     

I wouldn't build a dam to protect the water heater. I'd install a sump pump properly (in a pit) to protect the whole house. 
 

I just did a couple of them recently. Not that hard. 

jharry3 said:

Seems like if the water contained in the dam exceeds the height of a gas burner it will put the flame out.  If the gas doesn't shut itself down your basement will fill with gas.   (Is this possible?)

Electric would probably just trip the breaker.

Gas heaters would put out the flame, but they have failsafes.  The gas only stays on for the pilot if the flame it heating a thermocouple.  Cold sensor, no gas.  Most modern gas heaters are piezo ignition, so it wouldn't send any gas since it doesn't sense heat from a flame.  It would try a few times to ignite, each time sending miniscule amounts of gas, then after the third or fourth time it would just quit and give a fault code.

Electric won't trip the breaker.  The primary element is far enough off the floor that it would take thousands of gallons to fill the basement that high.

A common failure mode with water heater tanks is a very small leak first that slowly progresses.  It's very unlikely that it will just "blow" and dump millions of gallons of water.  Even if you lost all 40 gallons in the tank, and even if you had a tiny 24 x 24 basement, that translates to less than 1/8" of water on the floor.  Granted, it's something you want to avoid, but a simple water sensor should do the trick.

Even if the tank did "blow," unless you have a sump pump that can move 40 gallons per second, your basement is toast anyway.

I would get a generic shower pan or water heater pan and raise it 6" since the drain is 4" off the floor.  Connect hose.  Done.  Passive, doesn't rely on building a dam, doesn't use electronics that could fail.

In reply to Curtis73 (Forum Supporter) :

Thanks, I wasn't sure if gas would stay on.    But if the tank blows won't the water supply line  just flow unchecked and really fill the basement until it finds an outlet drain?

Edit: I see you addressed that...

Another option is an solenoid valve on the water feed connected to a moisture sensor near the water heater.  Kits are available from a number of suppliers. 

In reply to jharry3 :

I'm also a bit lax about the whole water heater thing.  My drains are at head-height in the basement, so I don't really have many options other than a sump pump.  My basement is unfinished with a concrete floor, and everything is on shelves because I get water in there when it rains.  When my water heater started leaking last year, I didn't even fix it for about three months... because concrete.

Curtis73 (Forum Supporter) said:

I would get a generic shower pan or water heater pan and raise it 6" since the drain is 4" off the floor.  Connect hose.  Done.  Passive, doesn't rely on building a dam, doesn't use electronics that could fail.

Our basement drain is about 4' up the wall. Which means that if our water heater failed we could keep alligators. 

4 inches or 4 feet? 

I misread your post. I thought you were trying to protect the water heater from a basement flood. I see now you're trying to protect the basement from a water heater flood. 
 

Doesn't change. You need a sump pump. Not a dam. 
 

When you dig the dump, it becomes the low point. It doesn't matter if your floor is pitched or not. 
 

A water heater failure is no different than a failure of any other part of the water supply system. It's gonna get water on the floor, and it's gonna keep flowing until you turn it off. 
 

I've never heard of a water heater rupturing and dumping 40 gallons quickly. Unless it's a failed T&P valve. If that happens, you've got a much bigger problem. (An explosion)

https://www.homedepot.com/p/FLOODMASTER-Water-Tank-Leak-Detection-and-Automatic-Shut-Off-System-for-3-4-in-Valve-Size-RS-094-3-4/204184370

Based on the suggestions here, I checked out my options a little more. The WH is at a high point on the basement pad and water could go pretty much any direction. Therefore, some simple sandbagging (without need for a discreet sump pump) should be all that's needed to point the water in the right direction. The existing hole is 20' away, but that's better than digging a hole in concrete.

With that in mind, what's a good way to mount a simple defense on a smooth concrete pad?

Again, I'm reluctant to put a hole right there in the middle, but if that's the only way, so be it. Intended slope is away from the pillar

I should also point out like VolvoHeretic mentioned that my drain height has only one quotation mark, not two :)

Put a pan under it and run a hose to your desired drain point.  Not sure why it doesn't have a pan under it already.  

In reply to 93gsxturbo :

Unfortunately with it being hard-lined in I don't think I could move it in the slightest. But I guess I was thinking too complicated -- I could just use something as a small outer ring and direct it that way. Sheesh I overthink things 

In reply to P3PPY :

Not sure what problem you are trying to fix...

- A small leak at the WH. This is the typical beginnings of failure (after many years of service). A pan would solve this, but pans are almost never used on concrete floors with nothing under them. 
 

- A massive 40 gallon rupture/ surge- A pan would do no good. This would cause damage, but is extremely rare. Best solution is probably to keep your insurance paid up. 
 

- A water leak in general (WH, plumbing, seepage through walls, etc)- This is best served by a sump pump. Plus aforementioned insurance. 
 

Other??

In reply to SV reX :

In case of major water spill from WH - or even AC condensate pump failure again - to isolate water to sump hole. So I'm trying to direct water to sump hole. Pan idea was floated with having a hose in the side as a method to direct the water. 

Water dam materials are sold for this purpose. It glues to the floor. It is soft enough to step on. 67" will set you back about $35 on Amazon. 

In reply to P3PPY :

I understand why the pan idea was floated. The problem is it won't address your concern. 
 

With the WH sitting in it, a pan has a capacity of only a few gallons. It has a 3/4" outlet (hose), but in the event if a catastrophic failure or rupture, the outlet won't flow enough to direct the water. It will capture less than 5 gallons. 
 

The pans are designed to contain small leaks that are persistent and could risk finished spaces below. A small leak on a concrete floor doesn't cause any damage. 

The full capacity of a 22" pan is 760 cubic inches. 1 gallon of water takes up 231 cubic inches. That means that the empty pan holds 3.29 gallons. With the WH sitting in it, it's more like 1 gallon. 

I had a 20 gallon water heater which rusted out the bottom perimeter weld. It never leaked until it let loose and flooded the bathroom in our cabin. Luckily I was there.

Toyman! said:

Water dam materials are sold for this purpose. It glues to the floor. It is soft enough to step on. 67" will set you back about $35 on Amazon. 

 

THIS! BINGO! 
I had no idea it existed and it's apparently exactly what I need for routing the potential flood toward a safe escape. Thank you!

Man, I was starting to think I was going to have to dig a hole, SV reX. 

So I got that barrier but the next step in the process was getting a sump pump, but I've been busy. I have been looking and everything I see wants me to have it primed, but I have zero water in my basement or the holes. Even if I did prime the pump, it would evaporate out before anything ever happened. Do they have sump pumps that do not require being primed? If so, what are my keywords? My little condensate pump doesn't seem to need to be primed, for instance. 

Sump pumps should be self priming.

Menards.com: Sump Pump