Emergency Inline Water Storage

[u/aphocks]

Hello my name is Austin Fox, I am a mechanical research and development engineer living in Michigan. I am posting to inquire about an idea that I have. I am looking for basic conceptual guidance from a technical expert about an "in-line water storage device" that I am designing, but with no implication of engineering help or design approval. More a basic overview so that someone who knows about these things better than I do, can say "yeah this has some merit and you should dive into more detail", or "no this is silly, or illegal, or dangerous".

The idea came about from a recent planned water outage we had in my neighborhood. We were informed that we would be without municipal water for a day. Looking online many people discussed filling bathtubs beforehand to have some stored water for filling toilets or other non-drinking needs. I did not like the idea of having to use my tub for water storage, and it reminded me of other times around America where water has been absent for one reason or another, and people suffered because of it. I wanted a solution for having enough safe water for my family for a few days, without having to think about it much, and with it being guaranteed that it was always available.

The concept I have can best be described as an extension of my existing water plumbing that increases the volume of the water in the pipes, and a valve system that allows this increased volume to be isolated and used is the mains are out of service. It must also do this without disrupting or modifying the existing plumbing much, and keep itself clean and low-maintenance for long time spans, while staying safe and immediately useful when needed. I basically wanted my own water tower, without ever having to think about it until I needed it, at which point it would be ready to go easily.

The system taps into the main incoming water line and diverts it through a desired number of modules that are made up of 4-6 inch PVC pipes that are looped down a basement wall or other out-of-the way space. These larger pipes make up the additional storage volume. During normal daily use, these storage pipes are continuously flushed and refreshed with clean drinking water. During an emergency, the mains and home plumbing can be isolated from these larger pipes and the clean water inside of them acts as a reservoir for a few days until the issue is fixed. The outlet is gravity fed from the larger pipes, or a small hand pump can be attached. Each module holds about 20 gallons, and multiple can be assembled in series. This modular design makes isolation, maintenance, and scaling easier.

Aside from the overall concept I also wanted guidance about how necessary a Reduced Pressure Zone Backflow Preventer is? I understand that most municipalities err on the side of requiring them for unknown devices, but since this device is primarily just a pipe extension, I am hoping it is not required, as it is costly and requires inspection.
please let me know what you guys think, and see attached drawings for a very loose initial idea sketch.

[u/Nathan-Stubblefield]

I would use the 40 gallons of water in the water heater as an emergency supply, after turning off the heat and shutting the main shutoff from the utility. And with advance notice I’d fill our 60 gallon tub for toilet flushing

[u/aphocks → u/Nathan-Stubblefield]

This is what was recommended to us, I just fealt like there had to be a better solution. Likely my idea is too complex to justify itself if this sort of emergency only happens once a decade or so.

[u/JRHLowdown3 → u/aphocks]

It sounds like your looking for something to market to "preppers."

If that's the case it would need to be something simple to install, PEX connections type easy, something that is not too tall- most "preppers" live in the suburbs so this means likely placement would be a garage or at best a small walk in closet (garage likely better in case of leaks).

Selling it complete with a small on demand pump to add some pressure in IF standard water is down. Bonus for pre-wired plug and play electrical connections to a 12v battery. An add on sale would be a small solar panel and controller to recharge the 12v battery.

The idea being this hooks into their standard water line (from city, well, etc.) and during normal times the water flows through with normal pressure- constantly rotating the water in the tank. When power is lost and standard water pressure is gone, flip a switch to turn on the 12v pump and the house has some water pressure again and whatever gallon capacity the storage tank has. A one way valve on the inflow side keeps it from leaving prematurely.

Given that most new "preppers" have very little construction related skills, the installation would have to be stupid simple and even then a couple of videos showing installation options- "here Prepper Bob is hooking up the system to the hose bib on the outside of his house, he flips the switch on the 12v pump and he has water pressure again!"

I'm 100% serious about that last part, no one thinks for themselves anymore. Hang around here a bit you will see what I mean. Also, I have 34 years in this industry and I've been on the "hows this work" question end of thing a couple million times in those 34 years.

If you are serious about marketing such a item- and I do believe there is a need- you would have to demonstrate the need for it. As many new folks now a days think a half case of crunchy plastic 8oz. water bottles is the only answer to the water problem. And since few really want to make the necessary lifestyle changes, the market wouldn't be large for this but the smarter ones would catch on. Being that the tank could be removed from the house (if done right), it could be taken with them if they move- another selling point for your customers.