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Community and Q&A

Water leak and flood detection and auto shut off solutions

fitchplate | Posted in General Questions on

We started using our new shower on the weekend; only to discover water oozing between the bathroom’s engineered floor planks and upon inspection it was raining in the cellar as the water drained down the plumbing stack vent … all due to an un-crimped pex fitting above at the 3 way shower control valve inside the wall. We were lucky the leak was on the down stream side of the control valve. The installer had tested everything with air but forgot one last minute adjustment in the shower.

What are peoples thoughts and experience with this?

I am inclined now to install a leak and flood protection solution. If this had happened when we were away, to an open supply appliance, or on the upstream side of any valves, it would have been catastrophic. Here is my thinking:

I understand that sinks, cloths’ washers, dishwashers and toilets can be made flood safe by using pressure sensitive shutoffs such as the Watts Flood Safe flex hoses on the hot and cold supply (accessible in the cabinets). I have one on a toilet, but not elsewhere. So I can retrofit these other locations.

But the shower/tub, hot water heater/boiler, incoming water service main supply in the utility room and cellar below would need water sensors that operate auto shut-off, full port ball valves. I can get appliance-specific sensors/shut-off units but these are expensive and seem redundant. Instead I am thinking of a whole house (auto shut off at the 3/4″ supply line) unit with 4 or 5 sensors (wired or wireless).

In fact, I am thinking that the cellar floor is the most important sensor location. It would pick up any water flowing/dripping from the main floor that is running down through penetrations (i.e. vents, sink drains; etc).

The range of prices would scar you. Here is a brand at the low end:

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  1. user-2310254 | | #1

    I considered installing one of the "event sensing" type shutoffs at the water meter of my new house. By the end of the project, there was no budget for what was a fairly expensive add-on. (Although water leaks can cause thousands of dollars in damage in minutes.) For the next house, I am looking at something like this:

    The price ($199) is reasonable--if it works as advertised.

  2. exeric | | #2

    Flitch Plate,
    The device you referenced (FloodStop) is highly rated. I bought that unit and have installed it on the main 3/4" water line coming into the house. This seems to be the most economical way of installing the device. I haven't yet installed all the sensors and wiring to the main box that will be required. That is one of my continuing projects. Really, the money isn't that much considering the downside of flooding in the house, but I certainly wouldn't get a separate device for every branch line in the house. The biggest cost is really the labor involved so if you do that yourself is not expensive.

    I have to thank you for bringing up your experience with your bathroom. I was in the process of debating whether I should put a sensor on the floor in the bathroom. The best places for the sensor are areas where there should never be water normally when you have watertight plumbing. The bathroom floor isn't necessarily one of those locations. Water from the tub and shower can get splashed about a bit. I'm now thinking that the best location for the sensor in the bathroom is in a very low walled container of some sort that is sitting on the floor. If it's located in a position where water does not splash into it then that low barrier will stop nuisance tripping of the valves but will still allow a low water level rise, perhaps 1/8" high walls, to allow useful tripping of the main water valve.

  3. exeric | | #3

    Something else to think about if you go this route. Water leaks aren't always obvious so you should have a separate wiring breakout section right at the main control box. That wiring should be clearly labeled as to which sensor each wire connects to. If quick disconnects are used at this breakout location then its easy to remove sensors one at a time to determine which sensor triggered the shutoff. I'm not sure there is more than one sensor input on the FloodStop controller so this is really a requirement to understand what happened. They advise daisy chaining them but that is not really a good idea if you want to know what is happening and to troubleshoot the system. Electrically it should work fine to have all the sensors wired in parallel at the controller as would be required for troubleshooting.

  4. fitchplate | | #4

    Steve ... WaterHero is for municipal systems; I have a well. But thanks.

    Eric ... I am assuming the Watts Flood Safe and other similar companies' pressure activated hot and cold flex lines for sinks, bidets, washing machine, icemakers and toilets will take care of the problem everywhere except the shower/tub assembly, boiler/hot water and any holding tanks.

    I was thinking of putting the sensors for the shower/tub on the floor behind the drywall and run the line through the sub-floor to the control/shut off. The whole area is opened up now to enable drying and repair. I may leave an access door or panel. I see there are wired and wireless sensors available with FloodStop. One could uses an oscillating saw to open up a whole behind the base molding and drywall and push a accessible sensor in the cavity the tub and shower.

    I agree that the savings and advantage of the whole house shut off; so I will put the valve in line on the main supply (a 3/4" pex line from my pressure tank).

    I will try sensors on the cellar floor below the vertical vent stacks will pick up leaks from above since I discovered that a catastrophic leak or flood will quickly run down the outside walls of the vent stacks and waste-water drains, through floor penetrations and into the basement.

    I learned the disadvantage of sealing/caulking floor penetrations. I had caulked every penetration except the tub/shower drains and vent stacks. All other sink and toilet drains are in partitions and I seriously caulked and sealed them with an idea of reducing air flow. If I had caulked the vent stack floor penetrations, I would have had water pooling and sitting on the main floor.

    It might sound silly to some but I can see using a fail-safe drain hole through the floors in the plumbing chases and interior partitions so any breaks or leaks will be drained off and into the basement.

  5. charlie_sullivan | | #5

    There should be a way to plug a drain hole like flitch describes with something that would block air flow effectively (and ideally even do so in a fire), but that would open under water pressure and let the water flow through. Anyone know of something made for that, or that would work well?

  6. Expert Member

    There are really two issues. First is testing the connections and valves that are installed after the waterlines and drains are pressure tested. The second is if you are comfortable trusting a properly installed plumbing system, appliances and fixtures.
    There are very few connections that can't be inspected once the whole system is finished. For those I install small circular vents in the walls so that I have access to them. I see testing them as part of commissioning a new house. (The shower valve is accessible and should have been tested before the cover plate was installed).
    Once a house is occupied and leak-free there are a few appliances that insurance claims show are the most vulnerable: Washing machines, hot water tanks, dishwashers and connections to refrigerators for ice makers. The first two should be installed on pans and good quality hoses used for the washer. So by elimination you can say that most of the risks can be mitigated. At that point you decide whether that is enough or whether as you have been discussing a few sensors would provide welcome back-up.
    i guess what I'm getting at is when building a new house, before wiring everything into an elaborate electronic network, I'd do the common sense things that minimized the threat first.

  7. exeric | | #7

    I agree that the basic plumbing should come under the rubric of tested and passed or tested and did NOT pass. If it did not pass then it is corrected. in Flitch Plates case that would be crimping the pex connection that wasn't crimped originally. Problem resolved and I wouldn't expect any further problems in that area except for acts of God. A bad installation isn't an act of God.

    What I would protect against is water plumbing and leaks WITHIN an appliance. That includes, like you said, refrigerators, washing machines, dishwashers, and hot water heaters. A drip pan underneath is not going to protect one from major leaks in the valves and plumbing within those appliances. Nor will a solid leak free hose connecting the appliance to the plumbing of the house.

    I've read many of the ratings for the Watts hoses and many people complained that they actually created leaks themselves. They have a fairly miserable rating on Amazon. I think the best bet for preventing non-manmade flooding is complete main water cutoff when those appliances fail. In the case of conventional plain-Jane water heaters that is WHEN, not IF. So, I think a device like the FloodStop is very worthwhile.

  8. exeric | | #8

    I should add that I'm a proponent of having drip pans under those appliances. If one then places the moisture sensor in the pan then hopefully it will turn the water valve off before the water overflows the pan and damages the flooring, or whatever.

  9. Expert Member

    I'm just in favour of narrowing down the potential trouble spots. Then perhaps a couple of sensors are a good idea.
    Watts hoses aren't much better than rubber ones. These ones are though;

  10. DarkNova | | #10

    I was thinking about this issue recently. One idea I had (although not actually implemented) was to install Z-Wave water sensors in vulnerable places. You could set up the Z-Wave rule to alarm, tell you which sensor detected water, and turn off the main water supply in the event that water is detected by one of the sensors. I've seen a Z-Wave whole house water valve that can shut off the water, or in my case, since we are on a well, I've thought about just using a Z-Wave relay connected to the well pump as that would be cheaper and easier to install. Just cut power to the well pump when water is detected. Not quite as good as a couple of gallons could flow from the pressure tank but that is minor compared to a flow of water going all weekend when you are out of town.

  11. fitchplate | | #11


    .... shuts off the electricity to the well pump when the sensor detects the leak.

  12. Expert Member
    MALCOLM TAYLOR | | #12

    Another thing builders could do to help is locate the main water shut-off in an accessible place where you are more likely to use it when you leave for a few days.

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